P1525
A Camshaft Position Actuator Control Open Circuit Bank 1
Causes
- Broken or disconnected wiring in the camshaft actuator control circuit
- Corroded, loose or damaged connector at the solenoid or DME
- Failed camshaft position actuator / solenoid (VANOS solenoid)
- Poor or missing ground or supply to the actuator
- Intermittent contact or short to voltage/ground in the harness
- Faulty DME (rare) or blown fuse/relay supplying the circuit
Symptoms
- Check Engine/MIL illuminated
- Reduced engine performance, rough idle or hesitation
- Poor low-end torque or drivability issues due to no cam timing adjustment
- Occasional limp-home behavior
- Related camshaft timing codes may also be stored
What to check
- Read freeze-frame and full DME fault list; note any related camshaft or VANOS codes
- Visual inspection of wiring and connectors at the actuator and DME for damage, corrosion, or disconnected pins
- Check fuses/relays that supply the DME/actuator power
- Measure battery voltage and good ground at vehicle chassis
- Backprobe actuator connector to measure supply, ground and control signal while cranking/idle
- Measure continuity and resistance of actuator coil and harness to DME with ignition off
Signal parameters
- Supply voltage (constant): battery voltage present at the actuator power pin with ignition on
- Control signal: PWM from DME when engine running — typically a switched/pulsed waveform between ~0 V and battery voltage (varies with load and rpm)
- Actuator coil resistance (typical): low-ohm coil (expect a finite resistance; an open/no continuity indicates failed coil or open wire) — measure with ignition off
- Expected behavior: no PWM when engine off; PWM appears when DME commands cam timing
- Fault indicator: infinite resistance (open) or very high resistance on continuity check
Diagnostic algorithm
- Retrieve and record all codes and freeze-frame data. Note related camshaft timing or sensor codes.
- Perform a visual inspection of the actuator connector, harness along the head/cylinder bank 1 routing, and DME connector for damage or corrosion.
- With ignition off, disconnect actuator and measure coil resistance between the actuator terminals. An open circuit indicates a bad actuator.
- Check continuity between the actuator connector terminals and the corresponding pins at the DME for opens/shorts. Repair any open or shorted wires.
- With harness connected, backprobe the connector with ignition ON and measure supply (should be battery voltage) and ground presence. If supply or ground missing, trace supply fuse/relay and ground point.
- Start engine (or crank) and measure the control pin with an oscilloscope or multimeter capable of reading PWM. Confirm a pulsed waveform appears when DME commands timing. No PWM while supply/ground are present indicates actuator or DME driver problem.
- If wiring and supply are good but no PWM and actuator is known good, consider DME driver fault — confirm by swapping with a known good actuator (if applicable) or consult manufacturer procedures before replacing DME.
- Repair or replace wiring, connector, or actuator as required. Clear codes and road-test to confirm resolution.
- If code returns after correct wiring and actuator replacement, proceed with DME-level diagnostics per BMW service information.
Likely causes
- Open or high-resistance wiring between DME and actuator (most common)
- Connector corrosion/terminal pushed out at the actuator or DME
- Failed actuator coil/solenoid
- Faulty ground or battery supply to the circuit
- DME driver fault (least likely)
Fault status
Similar codes
P1525
Throttle Body Service Required
Causes
- Broken or disconnected wiring in the camshaft actuator control circuit
- Corroded, loose or damaged connector at the solenoid or DME
- Failed camshaft position actuator / solenoid (VANOS solenoid)
- Poor or missing ground or supply to the actuator
- Intermittent contact or short to voltage/ground in the harness
- Faulty DME (rare) or blown fuse/relay supplying the circuit
Symptoms
- Check Engine/MIL illuminated
- Reduced engine performance, rough idle or hesitation
- Poor low-end torque or drivability issues due to no cam timing adjustment
- Occasional limp-home behavior
- Related camshaft timing codes may also be stored
What to check
- Read freeze-frame and full DME fault list; note any related camshaft or VANOS codes
- Visual inspection of wiring and connectors at the actuator and DME for damage, corrosion, or disconnected pins
- Check fuses/relays that supply the DME/actuator power
- Measure battery voltage and good ground at vehicle chassis
- Backprobe actuator connector to measure supply, ground and control signal while cranking/idle
- Measure continuity and resistance of actuator coil and harness to DME with ignition off
Signal parameters
- Supply voltage (constant): battery voltage present at the actuator power pin with ignition on
- Control signal: PWM from DME when engine running — typically a switched/pulsed waveform between ~0 V and battery voltage (varies with load and rpm)
- Actuator coil resistance (typical): low-ohm coil (expect a finite resistance; an open/no continuity indicates failed coil or open wire) — measure with ignition off
- Expected behavior: no PWM when engine off; PWM appears when DME commands cam timing
- Fault indicator: infinite resistance (open) or very high resistance on continuity check
Diagnostic algorithm
- Retrieve and record all codes and freeze-frame data. Note related camshaft timing or sensor codes.
- Perform a visual inspection of the actuator connector, harness along the head/cylinder bank 1 routing, and DME connector for damage or corrosion.
- With ignition off, disconnect actuator and measure coil resistance between the actuator terminals. An open circuit indicates a bad actuator.
- Check continuity between the actuator connector terminals and the corresponding pins at the DME for opens/shorts. Repair any open or shorted wires.
- With harness connected, backprobe the connector with ignition ON and measure supply (should be battery voltage) and ground presence. If supply or ground missing, trace supply fuse/relay and ground point.
- Start engine (or crank) and measure the control pin with an oscilloscope or multimeter capable of reading PWM. Confirm a pulsed waveform appears when DME commands timing. No PWM while supply/ground are present indicates actuator or DME driver problem.
- If wiring and supply are good but no PWM and actuator is known good, consider DME driver fault — confirm by swapping with a known good actuator (if applicable) or consult manufacturer procedures before replacing DME.
- Repair or replace wiring, connector, or actuator as required. Clear codes and road-test to confirm resolution.
- If code returns after correct wiring and actuator replacement, proceed with DME-level diagnostics per BMW service information.
Likely causes
- Open or high-resistance wiring between DME and actuator (most common)
- Connector corrosion/terminal pushed out at the actuator or DME
- Failed actuator coil/solenoid
- Faulty ground or battery supply to the circuit
- DME driver fault (least likely)
Fault status
Similar codes
P1525
Throttle Body Service Required
Causes
- Broken or disconnected wiring in the camshaft actuator control circuit
- Corroded, loose or damaged connector at the solenoid or DME
- Failed camshaft position actuator / solenoid (VANOS solenoid)
- Poor or missing ground or supply to the actuator
- Intermittent contact or short to voltage/ground in the harness
- Faulty DME (rare) or blown fuse/relay supplying the circuit
Symptoms
- Check Engine/MIL illuminated
- Reduced engine performance, rough idle or hesitation
- Poor low-end torque or drivability issues due to no cam timing adjustment
- Occasional limp-home behavior
- Related camshaft timing codes may also be stored
What to check
- Read freeze-frame and full DME fault list; note any related camshaft or VANOS codes
- Visual inspection of wiring and connectors at the actuator and DME for damage, corrosion, or disconnected pins
- Check fuses/relays that supply the DME/actuator power
- Measure battery voltage and good ground at vehicle chassis
- Backprobe actuator connector to measure supply, ground and control signal while cranking/idle
- Measure continuity and resistance of actuator coil and harness to DME with ignition off
Signal parameters
- Supply voltage (constant): battery voltage present at the actuator power pin with ignition on
- Control signal: PWM from DME when engine running — typically a switched/pulsed waveform between ~0 V and battery voltage (varies with load and rpm)
- Actuator coil resistance (typical): low-ohm coil (expect a finite resistance; an open/no continuity indicates failed coil or open wire) — measure with ignition off
- Expected behavior: no PWM when engine off; PWM appears when DME commands cam timing
- Fault indicator: infinite resistance (open) or very high resistance on continuity check
Diagnostic algorithm
- Retrieve and record all codes and freeze-frame data. Note related camshaft timing or sensor codes.
- Perform a visual inspection of the actuator connector, harness along the head/cylinder bank 1 routing, and DME connector for damage or corrosion.
- With ignition off, disconnect actuator and measure coil resistance between the actuator terminals. An open circuit indicates a bad actuator.
- Check continuity between the actuator connector terminals and the corresponding pins at the DME for opens/shorts. Repair any open or shorted wires.
- With harness connected, backprobe the connector with ignition ON and measure supply (should be battery voltage) and ground presence. If supply or ground missing, trace supply fuse/relay and ground point.
- Start engine (or crank) and measure the control pin with an oscilloscope or multimeter capable of reading PWM. Confirm a pulsed waveform appears when DME commands timing. No PWM while supply/ground are present indicates actuator or DME driver problem.
- If wiring and supply are good but no PWM and actuator is known good, consider DME driver fault — confirm by swapping with a known good actuator (if applicable) or consult manufacturer procedures before replacing DME.
- Repair or replace wiring, connector, or actuator as required. Clear codes and road-test to confirm resolution.
- If code returns after correct wiring and actuator replacement, proceed with DME-level diagnostics per BMW service information.
Likely causes
- Open or high-resistance wiring between DME and actuator (most common)
- Connector corrosion/terminal pushed out at the actuator or DME
- Failed actuator coil/solenoid
- Faulty ground or battery supply to the circuit
- DME driver fault (least likely)
Fault status
Similar codes
P1525
Throttle Body Service Required
Causes
- Broken or disconnected wiring in the camshaft actuator control circuit
- Corroded, loose or damaged connector at the solenoid or DME
- Failed camshaft position actuator / solenoid (VANOS solenoid)
- Poor or missing ground or supply to the actuator
- Intermittent contact or short to voltage/ground in the harness
- Faulty DME (rare) or blown fuse/relay supplying the circuit
Symptoms
- Check Engine/MIL illuminated
- Reduced engine performance, rough idle or hesitation
- Poor low-end torque or drivability issues due to no cam timing adjustment
- Occasional limp-home behavior
- Related camshaft timing codes may also be stored
What to check
- Read freeze-frame and full DME fault list; note any related camshaft or VANOS codes
- Visual inspection of wiring and connectors at the actuator and DME for damage, corrosion, or disconnected pins
- Check fuses/relays that supply the DME/actuator power
- Measure battery voltage and good ground at vehicle chassis
- Backprobe actuator connector to measure supply, ground and control signal while cranking/idle
- Measure continuity and resistance of actuator coil and harness to DME with ignition off
Signal parameters
- Supply voltage (constant): battery voltage present at the actuator power pin with ignition on
- Control signal: PWM from DME when engine running — typically a switched/pulsed waveform between ~0 V and battery voltage (varies with load and rpm)
- Actuator coil resistance (typical): low-ohm coil (expect a finite resistance; an open/no continuity indicates failed coil or open wire) — measure with ignition off
- Expected behavior: no PWM when engine off; PWM appears when DME commands cam timing
- Fault indicator: infinite resistance (open) or very high resistance on continuity check
Diagnostic algorithm
- Retrieve and record all codes and freeze-frame data. Note related camshaft timing or sensor codes.
- Perform a visual inspection of the actuator connector, harness along the head/cylinder bank 1 routing, and DME connector for damage or corrosion.
- With ignition off, disconnect actuator and measure coil resistance between the actuator terminals. An open circuit indicates a bad actuator.
- Check continuity between the actuator connector terminals and the corresponding pins at the DME for opens/shorts. Repair any open or shorted wires.
- With harness connected, backprobe the connector with ignition ON and measure supply (should be battery voltage) and ground presence. If supply or ground missing, trace supply fuse/relay and ground point.
- Start engine (or crank) and measure the control pin with an oscilloscope or multimeter capable of reading PWM. Confirm a pulsed waveform appears when DME commands timing. No PWM while supply/ground are present indicates actuator or DME driver problem.
- If wiring and supply are good but no PWM and actuator is known good, consider DME driver fault — confirm by swapping with a known good actuator (if applicable) or consult manufacturer procedures before replacing DME.
- Repair or replace wiring, connector, or actuator as required. Clear codes and road-test to confirm resolution.
- If code returns after correct wiring and actuator replacement, proceed with DME-level diagnostics per BMW service information.
Likely causes
- Open or high-resistance wiring between DME and actuator (most common)
- Connector corrosion/terminal pushed out at the actuator or DME
- Failed actuator coil/solenoid
- Faulty ground or battery supply to the circuit
- DME driver fault (least likely)
Fault status
Similar codes
P1525
Throttle Body Service Required
Causes
- Broken or disconnected wiring in the camshaft actuator control circuit
- Corroded, loose or damaged connector at the solenoid or DME
- Failed camshaft position actuator / solenoid (VANOS solenoid)
- Poor or missing ground or supply to the actuator
- Intermittent contact or short to voltage/ground in the harness
- Faulty DME (rare) or blown fuse/relay supplying the circuit
Symptoms
- Check Engine/MIL illuminated
- Reduced engine performance, rough idle or hesitation
- Poor low-end torque or drivability issues due to no cam timing adjustment
- Occasional limp-home behavior
- Related camshaft timing codes may also be stored
What to check
- Read freeze-frame and full DME fault list; note any related camshaft or VANOS codes
- Visual inspection of wiring and connectors at the actuator and DME for damage, corrosion, or disconnected pins
- Check fuses/relays that supply the DME/actuator power
- Measure battery voltage and good ground at vehicle chassis
- Backprobe actuator connector to measure supply, ground and control signal while cranking/idle
- Measure continuity and resistance of actuator coil and harness to DME with ignition off
Signal parameters
- Supply voltage (constant): battery voltage present at the actuator power pin with ignition on
- Control signal: PWM from DME when engine running — typically a switched/pulsed waveform between ~0 V and battery voltage (varies with load and rpm)
- Actuator coil resistance (typical): low-ohm coil (expect a finite resistance; an open/no continuity indicates failed coil or open wire) — measure with ignition off
- Expected behavior: no PWM when engine off; PWM appears when DME commands cam timing
- Fault indicator: infinite resistance (open) or very high resistance on continuity check
Diagnostic algorithm
- Retrieve and record all codes and freeze-frame data. Note related camshaft timing or sensor codes.
- Perform a visual inspection of the actuator connector, harness along the head/cylinder bank 1 routing, and DME connector for damage or corrosion.
- With ignition off, disconnect actuator and measure coil resistance between the actuator terminals. An open circuit indicates a bad actuator.
- Check continuity between the actuator connector terminals and the corresponding pins at the DME for opens/shorts. Repair any open or shorted wires.
- With harness connected, backprobe the connector with ignition ON and measure supply (should be battery voltage) and ground presence. If supply or ground missing, trace supply fuse/relay and ground point.
- Start engine (or crank) and measure the control pin with an oscilloscope or multimeter capable of reading PWM. Confirm a pulsed waveform appears when DME commands timing. No PWM while supply/ground are present indicates actuator or DME driver problem.
- If wiring and supply are good but no PWM and actuator is known good, consider DME driver fault — confirm by swapping with a known good actuator (if applicable) or consult manufacturer procedures before replacing DME.
- Repair or replace wiring, connector, or actuator as required. Clear codes and road-test to confirm resolution.
- If code returns after correct wiring and actuator replacement, proceed with DME-level diagnostics per BMW service information.
Likely causes
- Open or high-resistance wiring between DME and actuator (most common)
- Connector corrosion/terminal pushed out at the actuator or DME
- Failed actuator coil/solenoid
- Faulty ground or battery supply to the circuit
- DME driver fault (least likely)
Fault status
Similar codes
P1525
Throttle Body Service Required
Causes
- Broken or disconnected wiring in the camshaft actuator control circuit
- Corroded, loose or damaged connector at the solenoid or DME
- Failed camshaft position actuator / solenoid (VANOS solenoid)
- Poor or missing ground or supply to the actuator
- Intermittent contact or short to voltage/ground in the harness
- Faulty DME (rare) or blown fuse/relay supplying the circuit
Symptoms
- Check Engine/MIL illuminated
- Reduced engine performance, rough idle or hesitation
- Poor low-end torque or drivability issues due to no cam timing adjustment
- Occasional limp-home behavior
- Related camshaft timing codes may also be stored
What to check
- Read freeze-frame and full DME fault list; note any related camshaft or VANOS codes
- Visual inspection of wiring and connectors at the actuator and DME for damage, corrosion, or disconnected pins
- Check fuses/relays that supply the DME/actuator power
- Measure battery voltage and good ground at vehicle chassis
- Backprobe actuator connector to measure supply, ground and control signal while cranking/idle
- Measure continuity and resistance of actuator coil and harness to DME with ignition off
Signal parameters
- Supply voltage (constant): battery voltage present at the actuator power pin with ignition on
- Control signal: PWM from DME when engine running — typically a switched/pulsed waveform between ~0 V and battery voltage (varies with load and rpm)
- Actuator coil resistance (typical): low-ohm coil (expect a finite resistance; an open/no continuity indicates failed coil or open wire) — measure with ignition off
- Expected behavior: no PWM when engine off; PWM appears when DME commands cam timing
- Fault indicator: infinite resistance (open) or very high resistance on continuity check
Diagnostic algorithm
- Retrieve and record all codes and freeze-frame data. Note related camshaft timing or sensor codes.
- Perform a visual inspection of the actuator connector, harness along the head/cylinder bank 1 routing, and DME connector for damage or corrosion.
- With ignition off, disconnect actuator and measure coil resistance between the actuator terminals. An open circuit indicates a bad actuator.
- Check continuity between the actuator connector terminals and the corresponding pins at the DME for opens/shorts. Repair any open or shorted wires.
- With harness connected, backprobe the connector with ignition ON and measure supply (should be battery voltage) and ground presence. If supply or ground missing, trace supply fuse/relay and ground point.
- Start engine (or crank) and measure the control pin with an oscilloscope or multimeter capable of reading PWM. Confirm a pulsed waveform appears when DME commands timing. No PWM while supply/ground are present indicates actuator or DME driver problem.
- If wiring and supply are good but no PWM and actuator is known good, consider DME driver fault — confirm by swapping with a known good actuator (if applicable) or consult manufacturer procedures before replacing DME.
- Repair or replace wiring, connector, or actuator as required. Clear codes and road-test to confirm resolution.
- If code returns after correct wiring and actuator replacement, proceed with DME-level diagnostics per BMW service information.
Likely causes
- Open or high-resistance wiring between DME and actuator (most common)
- Connector corrosion/terminal pushed out at the actuator or DME
- Failed actuator coil/solenoid
- Faulty ground or battery supply to the circuit
- DME driver fault (least likely)
Fault status
Similar codes
P1525
Throttle Body Service Required
Causes
- Broken or disconnected wiring in the camshaft actuator control circuit
- Corroded, loose or damaged connector at the solenoid or DME
- Failed camshaft position actuator / solenoid (VANOS solenoid)
- Poor or missing ground or supply to the actuator
- Intermittent contact or short to voltage/ground in the harness
- Faulty DME (rare) or blown fuse/relay supplying the circuit
Symptoms
- Check Engine/MIL illuminated
- Reduced engine performance, rough idle or hesitation
- Poor low-end torque or drivability issues due to no cam timing adjustment
- Occasional limp-home behavior
- Related camshaft timing codes may also be stored
What to check
- Read freeze-frame and full DME fault list; note any related camshaft or VANOS codes
- Visual inspection of wiring and connectors at the actuator and DME for damage, corrosion, or disconnected pins
- Check fuses/relays that supply the DME/actuator power
- Measure battery voltage and good ground at vehicle chassis
- Backprobe actuator connector to measure supply, ground and control signal while cranking/idle
- Measure continuity and resistance of actuator coil and harness to DME with ignition off
Signal parameters
- Supply voltage (constant): battery voltage present at the actuator power pin with ignition on
- Control signal: PWM from DME when engine running — typically a switched/pulsed waveform between ~0 V and battery voltage (varies with load and rpm)
- Actuator coil resistance (typical): low-ohm coil (expect a finite resistance; an open/no continuity indicates failed coil or open wire) — measure with ignition off
- Expected behavior: no PWM when engine off; PWM appears when DME commands cam timing
- Fault indicator: infinite resistance (open) or very high resistance on continuity check
Diagnostic algorithm
- Retrieve and record all codes and freeze-frame data. Note related camshaft timing or sensor codes.
- Perform a visual inspection of the actuator connector, harness along the head/cylinder bank 1 routing, and DME connector for damage or corrosion.
- With ignition off, disconnect actuator and measure coil resistance between the actuator terminals. An open circuit indicates a bad actuator.
- Check continuity between the actuator connector terminals and the corresponding pins at the DME for opens/shorts. Repair any open or shorted wires.
- With harness connected, backprobe the connector with ignition ON and measure supply (should be battery voltage) and ground presence. If supply or ground missing, trace supply fuse/relay and ground point.
- Start engine (or crank) and measure the control pin with an oscilloscope or multimeter capable of reading PWM. Confirm a pulsed waveform appears when DME commands timing. No PWM while supply/ground are present indicates actuator or DME driver problem.
- If wiring and supply are good but no PWM and actuator is known good, consider DME driver fault — confirm by swapping with a known good actuator (if applicable) or consult manufacturer procedures before replacing DME.
- Repair or replace wiring, connector, or actuator as required. Clear codes and road-test to confirm resolution.
- If code returns after correct wiring and actuator replacement, proceed with DME-level diagnostics per BMW service information.
Likely causes
- Open or high-resistance wiring between DME and actuator (most common)
- Connector corrosion/terminal pushed out at the actuator or DME
- Failed actuator coil/solenoid
- Faulty ground or battery supply to the circuit
- DME driver fault (least likely)
Fault status
Similar codes
P1525
Throttle Body ServiceRequired
Causes
- Broken or disconnected wiring in the camshaft actuator control circuit
- Corroded, loose or damaged connector at the solenoid or DME
- Failed camshaft position actuator / solenoid (VANOS solenoid)
- Poor or missing ground or supply to the actuator
- Intermittent contact or short to voltage/ground in the harness
- Faulty DME (rare) or blown fuse/relay supplying the circuit
Symptoms
- Check Engine/MIL illuminated
- Reduced engine performance, rough idle or hesitation
- Poor low-end torque or drivability issues due to no cam timing adjustment
- Occasional limp-home behavior
- Related camshaft timing codes may also be stored
What to check
- Read freeze-frame and full DME fault list; note any related camshaft or VANOS codes
- Visual inspection of wiring and connectors at the actuator and DME for damage, corrosion, or disconnected pins
- Check fuses/relays that supply the DME/actuator power
- Measure battery voltage and good ground at vehicle chassis
- Backprobe actuator connector to measure supply, ground and control signal while cranking/idle
- Measure continuity and resistance of actuator coil and harness to DME with ignition off
Signal parameters
- Supply voltage (constant): battery voltage present at the actuator power pin with ignition on
- Control signal: PWM from DME when engine running — typically a switched/pulsed waveform between ~0 V and battery voltage (varies with load and rpm)
- Actuator coil resistance (typical): low-ohm coil (expect a finite resistance; an open/no continuity indicates failed coil or open wire) — measure with ignition off
- Expected behavior: no PWM when engine off; PWM appears when DME commands cam timing
- Fault indicator: infinite resistance (open) or very high resistance on continuity check
Diagnostic algorithm
- Retrieve and record all codes and freeze-frame data. Note related camshaft timing or sensor codes.
- Perform a visual inspection of the actuator connector, harness along the head/cylinder bank 1 routing, and DME connector for damage or corrosion.
- With ignition off, disconnect actuator and measure coil resistance between the actuator terminals. An open circuit indicates a bad actuator.
- Check continuity between the actuator connector terminals and the corresponding pins at the DME for opens/shorts. Repair any open or shorted wires.
- With harness connected, backprobe the connector with ignition ON and measure supply (should be battery voltage) and ground presence. If supply or ground missing, trace supply fuse/relay and ground point.
- Start engine (or crank) and measure the control pin with an oscilloscope or multimeter capable of reading PWM. Confirm a pulsed waveform appears when DME commands timing. No PWM while supply/ground are present indicates actuator or DME driver problem.
- If wiring and supply are good but no PWM and actuator is known good, consider DME driver fault — confirm by swapping with a known good actuator (if applicable) or consult manufacturer procedures before replacing DME.
- Repair or replace wiring, connector, or actuator as required. Clear codes and road-test to confirm resolution.
- If code returns after correct wiring and actuator replacement, proceed with DME-level diagnostics per BMW service information.
Likely causes
- Open or high-resistance wiring between DME and actuator (most common)
- Connector corrosion/terminal pushed out at the actuator or DME
- Failed actuator coil/solenoid
- Faulty ground or battery supply to the circuit
- DME driver fault (least likely)
Fault status
Similar codes
P1525
Throttle Body Service Required
Causes
- Broken or disconnected wiring in the camshaft actuator control circuit
- Corroded, loose or damaged connector at the solenoid or DME
- Failed camshaft position actuator / solenoid (VANOS solenoid)
- Poor or missing ground or supply to the actuator
- Intermittent contact or short to voltage/ground in the harness
- Faulty DME (rare) or blown fuse/relay supplying the circuit
Symptoms
- Check Engine/MIL illuminated
- Reduced engine performance, rough idle or hesitation
- Poor low-end torque or drivability issues due to no cam timing adjustment
- Occasional limp-home behavior
- Related camshaft timing codes may also be stored
What to check
- Read freeze-frame and full DME fault list; note any related camshaft or VANOS codes
- Visual inspection of wiring and connectors at the actuator and DME for damage, corrosion, or disconnected pins
- Check fuses/relays that supply the DME/actuator power
- Measure battery voltage and good ground at vehicle chassis
- Backprobe actuator connector to measure supply, ground and control signal while cranking/idle
- Measure continuity and resistance of actuator coil and harness to DME with ignition off
Signal parameters
- Supply voltage (constant): battery voltage present at the actuator power pin with ignition on
- Control signal: PWM from DME when engine running — typically a switched/pulsed waveform between ~0 V and battery voltage (varies with load and rpm)
- Actuator coil resistance (typical): low-ohm coil (expect a finite resistance; an open/no continuity indicates failed coil or open wire) — measure with ignition off
- Expected behavior: no PWM when engine off; PWM appears when DME commands cam timing
- Fault indicator: infinite resistance (open) or very high resistance on continuity check
Diagnostic algorithm
- Retrieve and record all codes and freeze-frame data. Note related camshaft timing or sensor codes.
- Perform a visual inspection of the actuator connector, harness along the head/cylinder bank 1 routing, and DME connector for damage or corrosion.
- With ignition off, disconnect actuator and measure coil resistance between the actuator terminals. An open circuit indicates a bad actuator.
- Check continuity between the actuator connector terminals and the corresponding pins at the DME for opens/shorts. Repair any open or shorted wires.
- With harness connected, backprobe the connector with ignition ON and measure supply (should be battery voltage) and ground presence. If supply or ground missing, trace supply fuse/relay and ground point.
- Start engine (or crank) and measure the control pin with an oscilloscope or multimeter capable of reading PWM. Confirm a pulsed waveform appears when DME commands timing. No PWM while supply/ground are present indicates actuator or DME driver problem.
- If wiring and supply are good but no PWM and actuator is known good, consider DME driver fault — confirm by swapping with a known good actuator (if applicable) or consult manufacturer procedures before replacing DME.
- Repair or replace wiring, connector, or actuator as required. Clear codes and road-test to confirm resolution.
- If code returns after correct wiring and actuator replacement, proceed with DME-level diagnostics per BMW service information.
Likely causes
- Open or high-resistance wiring between DME and actuator (most common)
- Connector corrosion/terminal pushed out at the actuator or DME
- Failed actuator coil/solenoid
- Faulty ground or battery supply to the circuit
- DME driver fault (least likely)
Fault status
Similar codes
P1525
Air Bypass Valve System
Causes
- Broken or disconnected wiring in the camshaft actuator control circuit
- Corroded, loose or damaged connector at the solenoid or DME
- Failed camshaft position actuator / solenoid (VANOS solenoid)
- Poor or missing ground or supply to the actuator
- Intermittent contact or short to voltage/ground in the harness
- Faulty DME (rare) or blown fuse/relay supplying the circuit
Symptoms
- Check Engine/MIL illuminated
- Reduced engine performance, rough idle or hesitation
- Poor low-end torque or drivability issues due to no cam timing adjustment
- Occasional limp-home behavior
- Related camshaft timing codes may also be stored
What to check
- Read freeze-frame and full DME fault list; note any related camshaft or VANOS codes
- Visual inspection of wiring and connectors at the actuator and DME for damage, corrosion, or disconnected pins
- Check fuses/relays that supply the DME/actuator power
- Measure battery voltage and good ground at vehicle chassis
- Backprobe actuator connector to measure supply, ground and control signal while cranking/idle
- Measure continuity and resistance of actuator coil and harness to DME with ignition off
Signal parameters
- Supply voltage (constant): battery voltage present at the actuator power pin with ignition on
- Control signal: PWM from DME when engine running — typically a switched/pulsed waveform between ~0 V and battery voltage (varies with load and rpm)
- Actuator coil resistance (typical): low-ohm coil (expect a finite resistance; an open/no continuity indicates failed coil or open wire) — measure with ignition off
- Expected behavior: no PWM when engine off; PWM appears when DME commands cam timing
- Fault indicator: infinite resistance (open) or very high resistance on continuity check
Diagnostic algorithm
- Retrieve and record all codes and freeze-frame data. Note related camshaft timing or sensor codes.
- Perform a visual inspection of the actuator connector, harness along the head/cylinder bank 1 routing, and DME connector for damage or corrosion.
- With ignition off, disconnect actuator and measure coil resistance between the actuator terminals. An open circuit indicates a bad actuator.
- Check continuity between the actuator connector terminals and the corresponding pins at the DME for opens/shorts. Repair any open or shorted wires.
- With harness connected, backprobe the connector with ignition ON and measure supply (should be battery voltage) and ground presence. If supply or ground missing, trace supply fuse/relay and ground point.
- Start engine (or crank) and measure the control pin with an oscilloscope or multimeter capable of reading PWM. Confirm a pulsed waveform appears when DME commands timing. No PWM while supply/ground are present indicates actuator or DME driver problem.
- If wiring and supply are good but no PWM and actuator is known good, consider DME driver fault — confirm by swapping with a known good actuator (if applicable) or consult manufacturer procedures before replacing DME.
- Repair or replace wiring, connector, or actuator as required. Clear codes and road-test to confirm resolution.
- If code returns after correct wiring and actuator replacement, proceed with DME-level diagnostics per BMW service information.
Likely causes
- Open or high-resistance wiring between DME and actuator (most common)
- Connector corrosion/terminal pushed out at the actuator or DME
- Failed actuator coil/solenoid
- Faulty ground or battery supply to the circuit
- DME driver fault (least likely)
Fault status
Similar codes
Available brands with manuals
LAND ROVER 1
Land Rover Defender Workshop Manual 1999-2002 MY
Workshop ManualP1525
Defrost Sensor
Causes
- Broken or disconnected wiring in the camshaft actuator control circuit
- Corroded, loose or damaged connector at the solenoid or DME
- Failed camshaft position actuator / solenoid (VANOS solenoid)
- Poor or missing ground or supply to the actuator
- Intermittent contact or short to voltage/ground in the harness
- Faulty DME (rare) or blown fuse/relay supplying the circuit
Symptoms
- Check Engine/MIL illuminated
- Reduced engine performance, rough idle or hesitation
- Poor low-end torque or drivability issues due to no cam timing adjustment
- Occasional limp-home behavior
- Related camshaft timing codes may also be stored
What to check
- Read freeze-frame and full DME fault list; note any related camshaft or VANOS codes
- Visual inspection of wiring and connectors at the actuator and DME for damage, corrosion, or disconnected pins
- Check fuses/relays that supply the DME/actuator power
- Measure battery voltage and good ground at vehicle chassis
- Backprobe actuator connector to measure supply, ground and control signal while cranking/idle
- Measure continuity and resistance of actuator coil and harness to DME with ignition off
Signal parameters
- Supply voltage (constant): battery voltage present at the actuator power pin with ignition on
- Control signal: PWM from DME when engine running — typically a switched/pulsed waveform between ~0 V and battery voltage (varies with load and rpm)
- Actuator coil resistance (typical): low-ohm coil (expect a finite resistance; an open/no continuity indicates failed coil or open wire) — measure with ignition off
- Expected behavior: no PWM when engine off; PWM appears when DME commands cam timing
- Fault indicator: infinite resistance (open) or very high resistance on continuity check
Diagnostic algorithm
- Retrieve and record all codes and freeze-frame data. Note related camshaft timing or sensor codes.
- Perform a visual inspection of the actuator connector, harness along the head/cylinder bank 1 routing, and DME connector for damage or corrosion.
- With ignition off, disconnect actuator and measure coil resistance between the actuator terminals. An open circuit indicates a bad actuator.
- Check continuity between the actuator connector terminals and the corresponding pins at the DME for opens/shorts. Repair any open or shorted wires.
- With harness connected, backprobe the connector with ignition ON and measure supply (should be battery voltage) and ground presence. If supply or ground missing, trace supply fuse/relay and ground point.
- Start engine (or crank) and measure the control pin with an oscilloscope or multimeter capable of reading PWM. Confirm a pulsed waveform appears when DME commands timing. No PWM while supply/ground are present indicates actuator or DME driver problem.
- If wiring and supply are good but no PWM and actuator is known good, consider DME driver fault — confirm by swapping with a known good actuator (if applicable) or consult manufacturer procedures before replacing DME.
- Repair or replace wiring, connector, or actuator as required. Clear codes and road-test to confirm resolution.
- If code returns after correct wiring and actuator replacement, proceed with DME-level diagnostics per BMW service information.
Likely causes
- Open or high-resistance wiring between DME and actuator (most common)
- Connector corrosion/terminal pushed out at the actuator or DME
- Failed actuator coil/solenoid
- Faulty ground or battery supply to the circuit
- DME driver fault (least likely)
Fault status
Similar codes
P1525
Throttle Body Service Required
Causes
- Broken or disconnected wiring in the camshaft actuator control circuit
- Corroded, loose or damaged connector at the solenoid or DME
- Failed camshaft position actuator / solenoid (VANOS solenoid)
- Poor or missing ground or supply to the actuator
- Intermittent contact or short to voltage/ground in the harness
- Faulty DME (rare) or blown fuse/relay supplying the circuit
Symptoms
- Check Engine/MIL illuminated
- Reduced engine performance, rough idle or hesitation
- Poor low-end torque or drivability issues due to no cam timing adjustment
- Occasional limp-home behavior
- Related camshaft timing codes may also be stored
What to check
- Read freeze-frame and full DME fault list; note any related camshaft or VANOS codes
- Visual inspection of wiring and connectors at the actuator and DME for damage, corrosion, or disconnected pins
- Check fuses/relays that supply the DME/actuator power
- Measure battery voltage and good ground at vehicle chassis
- Backprobe actuator connector to measure supply, ground and control signal while cranking/idle
- Measure continuity and resistance of actuator coil and harness to DME with ignition off
Signal parameters
- Supply voltage (constant): battery voltage present at the actuator power pin with ignition on
- Control signal: PWM from DME when engine running — typically a switched/pulsed waveform between ~0 V and battery voltage (varies with load and rpm)
- Actuator coil resistance (typical): low-ohm coil (expect a finite resistance; an open/no continuity indicates failed coil or open wire) — measure with ignition off
- Expected behavior: no PWM when engine off; PWM appears when DME commands cam timing
- Fault indicator: infinite resistance (open) or very high resistance on continuity check
Diagnostic algorithm
- Retrieve and record all codes and freeze-frame data. Note related camshaft timing or sensor codes.
- Perform a visual inspection of the actuator connector, harness along the head/cylinder bank 1 routing, and DME connector for damage or corrosion.
- With ignition off, disconnect actuator and measure coil resistance between the actuator terminals. An open circuit indicates a bad actuator.
- Check continuity between the actuator connector terminals and the corresponding pins at the DME for opens/shorts. Repair any open or shorted wires.
- With harness connected, backprobe the connector with ignition ON and measure supply (should be battery voltage) and ground presence. If supply or ground missing, trace supply fuse/relay and ground point.
- Start engine (or crank) and measure the control pin with an oscilloscope or multimeter capable of reading PWM. Confirm a pulsed waveform appears when DME commands timing. No PWM while supply/ground are present indicates actuator or DME driver problem.
- If wiring and supply are good but no PWM and actuator is known good, consider DME driver fault — confirm by swapping with a known good actuator (if applicable) or consult manufacturer procedures before replacing DME.
- Repair or replace wiring, connector, or actuator as required. Clear codes and road-test to confirm resolution.
- If code returns after correct wiring and actuator replacement, proceed with DME-level diagnostics per BMW service information.
Likely causes
- Open or high-resistance wiring between DME and actuator (most common)
- Connector corrosion/terminal pushed out at the actuator or DME
- Failed actuator coil/solenoid
- Faulty ground or battery supply to the circuit
- DME driver fault (least likely)
Fault status
Similar codes
P1525
Intake Camshaft Control Circuit Bank 1 Electrical Malfunction
Causes
- Broken or disconnected wiring in the camshaft actuator control circuit
- Corroded, loose or damaged connector at the solenoid or DME
- Failed camshaft position actuator / solenoid (VANOS solenoid)
- Poor or missing ground or supply to the actuator
- Intermittent contact or short to voltage/ground in the harness
- Faulty DME (rare) or blown fuse/relay supplying the circuit
Symptoms
- Check Engine/MIL illuminated
- Reduced engine performance, rough idle or hesitation
- Poor low-end torque or drivability issues due to no cam timing adjustment
- Occasional limp-home behavior
- Related camshaft timing codes may also be stored
What to check
- Read freeze-frame and full DME fault list; note any related camshaft or VANOS codes
- Visual inspection of wiring and connectors at the actuator and DME for damage, corrosion, or disconnected pins
- Check fuses/relays that supply the DME/actuator power
- Measure battery voltage and good ground at vehicle chassis
- Backprobe actuator connector to measure supply, ground and control signal while cranking/idle
- Measure continuity and resistance of actuator coil and harness to DME with ignition off
Signal parameters
- Supply voltage (constant): battery voltage present at the actuator power pin with ignition on
- Control signal: PWM from DME when engine running — typically a switched/pulsed waveform between ~0 V and battery voltage (varies with load and rpm)
- Actuator coil resistance (typical): low-ohm coil (expect a finite resistance; an open/no continuity indicates failed coil or open wire) — measure with ignition off
- Expected behavior: no PWM when engine off; PWM appears when DME commands cam timing
- Fault indicator: infinite resistance (open) or very high resistance on continuity check
Diagnostic algorithm
- Retrieve and record all codes and freeze-frame data. Note related camshaft timing or sensor codes.
- Perform a visual inspection of the actuator connector, harness along the head/cylinder bank 1 routing, and DME connector for damage or corrosion.
- With ignition off, disconnect actuator and measure coil resistance between the actuator terminals. An open circuit indicates a bad actuator.
- Check continuity between the actuator connector terminals and the corresponding pins at the DME for opens/shorts. Repair any open or shorted wires.
- With harness connected, backprobe the connector with ignition ON and measure supply (should be battery voltage) and ground presence. If supply or ground missing, trace supply fuse/relay and ground point.
- Start engine (or crank) and measure the control pin with an oscilloscope or multimeter capable of reading PWM. Confirm a pulsed waveform appears when DME commands timing. No PWM while supply/ground are present indicates actuator or DME driver problem.
- If wiring and supply are good but no PWM and actuator is known good, consider DME driver fault — confirm by swapping with a known good actuator (if applicable) or consult manufacturer procedures before replacing DME.
- Repair or replace wiring, connector, or actuator as required. Clear codes and road-test to confirm resolution.
- If code returns after correct wiring and actuator replacement, proceed with DME-level diagnostics per BMW service information.
Likely causes
- Open or high-resistance wiring between DME and actuator (most common)
- Connector corrosion/terminal pushed out at the actuator or DME
- Failed actuator coil/solenoid
- Faulty ground or battery supply to the circuit
- DME driver fault (least likely)
