Code
P0379
Generic
P — Powertrain
Timing Reference High Resolution Signal B No Pulses
Views:
UK: 15
EN: 12
RU: 11
AI status
Completed
Completed
100%
Causes
- Open or shorted wiring between HR timing sensor B and the engine control module
- Failed high-resolution timing reference sensor (cam/crank/shaft-sensor B)
- Poor connector connection (corrosion, bent pins, water intrusion)
- Loss of sensor supply voltage or ground
- Faulty engine control module input circuit
- Physical damage to tone wheel or reluctor (missing teeth, debris)
Symptoms
- Hard start or no-crank/no-start conditions in some cases
- Check Engine Light (MIL) illuminated
- Engine may crank but not run, or run rough
- Misfires, reduced performance or stalling
- Fault codes relating to cam/crank correlation or fuel injection timing
What to check
- Confirm DTC P0379 is current and note freeze frame data
- Visual inspection of sensor B connector, wiring harness and routing for damage
- Check for water, corrosion, or bent pins at connectors
- Verify sensor supply voltage and ground at the connector with key on
- Backprobe signal wire while cranking/running with an oscilloscope or logic probe
- Inspect tone wheel/reluctor for missing or damaged teeth and proper alignment
Signal parameters
- No pulses on the HR signal wire when engine is cranking/running (primary symptom)
- Expected waveform: high-resolution square-wave or TTL-level pulses synchronized to crank/cam rotation
- Typical voltage levels: 0–5 V digital-style pulses (may vary by manufacturer)
- Pulse frequency: proportional to engine speed (hundreds to thousands of pulses per minute)
- Duty cycle and pulse width depend on tone wheel design; ECU expects consistent periodic pulses
Diagnostic algorithm
- Read and record freeze-frame and all related codes. Do not replace parts without verification.
- Perform a careful visual inspection of sensor B, connectors and harness for damage, corrosion, or loose pins.
- With key ON (engine OFF), verify sensor supply (reference voltage) and ground at the sensor connector using a multimeter. Compare to spec.
- Backprobe the signal lead and check for pulses while cranking/starting with an oscilloscope. Confirm presence or absence of expected waveform.
- If no signal, wiggle wiring harness and connectors while monitoring for intermittent pulses to detect breaks or shorts.
- Measure sensor resistance (if applicable) and compare to specification; test sensor per manufacturer procedure.
- Inspect reluctor/tone wheel for damaged/missing teeth, correct installation and timing alignment.
- Check continuity and resistance of wiring between sensor and ECU; look for shorts to power or ground.
- If wiring and sensor check good but no signal, use scope to probe ECU input pin to verify whether pulses reach the controller. If pulses are present at ECU and code persists, suspect ECM input fault.
- After repair, clear codes and perform a road/crank test to confirm pulses are detected and code does not return.
Likely causes
- Broken or disconnected harness to sensor B
- Corroded connector at sensor or module
- Failed sensor (open internal circuit or electronics)
- Damaged reluctor/tone wheel (missing or damaged pulses)
- Faulty ECU input stage (less common)
Fault status
Status
No pulses detected from Timing Reference High Resolution Signal B circuit — ECM/PCM expected HR timing pulses during cranking/running but input remained inactive.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
Similar codes
Workshop Manuals
Available brands with manuals
1
LAND ROVER 2
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop ManualOfficial workshop manual for the Land Rover Defender 300Tdi (from 1996 model year). Contains specifications, adjustment, fault diagnosis and step-by-step repair and overhaul procedures for engine, transmission, axles, suspension, brakes, electrical and body. Intended for dealer workshops and trained technicians.
199,00 UAH
Land Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop ManualWorkshop Manual Supplement and Body Repair Manual for the Land Rover Defender. Includes general specifications, maintenance schedules, tuning data and step‑by‑step repair procedures for engine, transmission, suspension, brakes, electrical and body repairs. Covers Defender models from 1999 and 2002 model years.
199,00 UAH
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Code
P0379
GWM
P — Powertrain
- No Timed B Signals
Views:
UK: 1
EN: 1
RU: 1
AI status
Completed
Completed
100%
Causes
- Open or shorted wiring between HR timing sensor B and the engine control module
- Failed high-resolution timing reference sensor (cam/crank/shaft-sensor B)
- Poor connector connection (corrosion, bent pins, water intrusion)
- Loss of sensor supply voltage or ground
- Faulty engine control module input circuit
- Physical damage to tone wheel or reluctor (missing teeth, debris)
Symptoms
- Hard start or no-crank/no-start conditions in some cases
- Check Engine Light (MIL) illuminated
- Engine may crank but not run, or run rough
- Misfires, reduced performance or stalling
- Fault codes relating to cam/crank correlation or fuel injection timing
What to check
- Confirm DTC P0379 is current and note freeze frame data
- Visual inspection of sensor B connector, wiring harness and routing for damage
- Check for water, corrosion, or bent pins at connectors
- Verify sensor supply voltage and ground at the connector with key on
- Backprobe signal wire while cranking/running with an oscilloscope or logic probe
- Inspect tone wheel/reluctor for missing or damaged teeth and proper alignment
Signal parameters
- No pulses on the HR signal wire when engine is cranking/running (primary symptom)
- Expected waveform: high-resolution square-wave or TTL-level pulses synchronized to crank/cam rotation
- Typical voltage levels: 0–5 V digital-style pulses (may vary by manufacturer)
- Pulse frequency: proportional to engine speed (hundreds to thousands of pulses per minute)
- Duty cycle and pulse width depend on tone wheel design; ECU expects consistent periodic pulses
Diagnostic algorithm
- Read and record freeze-frame and all related codes. Do not replace parts without verification.
- Perform a careful visual inspection of sensor B, connectors and harness for damage, corrosion, or loose pins.
- With key ON (engine OFF), verify sensor supply (reference voltage) and ground at the sensor connector using a multimeter. Compare to spec.
- Backprobe the signal lead and check for pulses while cranking/starting with an oscilloscope. Confirm presence or absence of expected waveform.
- If no signal, wiggle wiring harness and connectors while monitoring for intermittent pulses to detect breaks or shorts.
- Measure sensor resistance (if applicable) and compare to specification; test sensor per manufacturer procedure.
- Inspect reluctor/tone wheel for damaged/missing teeth, correct installation and timing alignment.
- Check continuity and resistance of wiring between sensor and ECU; look for shorts to power or ground.
- If wiring and sensor check good but no signal, use scope to probe ECU input pin to verify whether pulses reach the controller. If pulses are present at ECU and code persists, suspect ECM input fault.
- After repair, clear codes and perform a road/crank test to confirm pulses are detected and code does not return.
Likely causes
- Broken or disconnected harness to sensor B
- Corroded connector at sensor or module
- Failed sensor (open internal circuit or electronics)
- Damaged reluctor/tone wheel (missing or damaged pulses)
- Faulty ECU input stage (less common)
Fault status
Status
No pulses detected from Timing Reference High Resolution Signal B circuit — ECM/PCM expected HR timing pulses during cranking/running but input remained inactive.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
Similar codes
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Code
P0379
HUMMER
P — Powertrain
Timing Reference High Resolution Signal B No Pulses
Views:
UK: 2
EN: 9
RU: 3
AI status
Completed
Completed
100%
Causes
- Open or shorted wiring between HR timing sensor B and the engine control module
- Failed high-resolution timing reference sensor (cam/crank/shaft-sensor B)
- Poor connector connection (corrosion, bent pins, water intrusion)
- Loss of sensor supply voltage or ground
- Faulty engine control module input circuit
- Physical damage to tone wheel or reluctor (missing teeth, debris)
Symptoms
- Hard start or no-crank/no-start conditions in some cases
- Check Engine Light (MIL) illuminated
- Engine may crank but not run, or run rough
- Misfires, reduced performance or stalling
- Fault codes relating to cam/crank correlation or fuel injection timing
What to check
- Confirm DTC P0379 is current and note freeze frame data
- Visual inspection of sensor B connector, wiring harness and routing for damage
- Check for water, corrosion, or bent pins at connectors
- Verify sensor supply voltage and ground at the connector with key on
- Backprobe signal wire while cranking/running with an oscilloscope or logic probe
- Inspect tone wheel/reluctor for missing or damaged teeth and proper alignment
Signal parameters
- No pulses on the HR signal wire when engine is cranking/running (primary symptom)
- Expected waveform: high-resolution square-wave or TTL-level pulses synchronized to crank/cam rotation
- Typical voltage levels: 0–5 V digital-style pulses (may vary by manufacturer)
- Pulse frequency: proportional to engine speed (hundreds to thousands of pulses per minute)
- Duty cycle and pulse width depend on tone wheel design; ECU expects consistent periodic pulses
Diagnostic algorithm
- Read and record freeze-frame and all related codes. Do not replace parts without verification.
- Perform a careful visual inspection of sensor B, connectors and harness for damage, corrosion, or loose pins.
- With key ON (engine OFF), verify sensor supply (reference voltage) and ground at the sensor connector using a multimeter. Compare to spec.
- Backprobe the signal lead and check for pulses while cranking/starting with an oscilloscope. Confirm presence or absence of expected waveform.
- If no signal, wiggle wiring harness and connectors while monitoring for intermittent pulses to detect breaks or shorts.
- Measure sensor resistance (if applicable) and compare to specification; test sensor per manufacturer procedure.
- Inspect reluctor/tone wheel for damaged/missing teeth, correct installation and timing alignment.
- Check continuity and resistance of wiring between sensor and ECU; look for shorts to power or ground.
- If wiring and sensor check good but no signal, use scope to probe ECU input pin to verify whether pulses reach the controller. If pulses are present at ECU and code persists, suspect ECM input fault.
- After repair, clear codes and perform a road/crank test to confirm pulses are detected and code does not return.
Likely causes
- Broken or disconnected harness to sensor B
- Corroded connector at sensor or module
- Failed sensor (open internal circuit or electronics)
- Damaged reluctor/tone wheel (missing or damaged pulses)
- Faulty ECU input stage (less common)
Fault status
Status
No pulses detected from Timing Reference High Resolution Signal B circuit — ECM/PCM expected HR timing pulses during cranking/running but input remained inactive.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email