Code
P0020
Generic
P — Powertrain
A Camshaft Position Actuator A Control Circuit/Open Bank 2
Views:
UK: 27
EN: 40
RU: 41
AI status
Completed
Completed
100%
Causes
- Open or broken wiring in the actuator control circuit
- Corroded/loose connector or poor pin contact at the actuator
- Failed camshaft position actuator (solenoid/phaser)
- Blown fuse or faulty relay supplying the circuit
- PCM/ECM internal fault or damaged driver transistor
- Low engine oil pressure, contaminated oil, or wrong oil viscosity causing phaser to stick
Symptoms
- Malfunction Indicator Lamp (MIL/Check Engine) illuminated
- Reduced engine performance or limp mode in some vehicles
- Rough idle, hesitation or misfire on affected bank
- Poor fuel economy
- Engine may run noisier or have increased vibration
- Possible difficulty starting or stalling in severe cases
What to check
- Read stored codes and freeze-frame data with a scan tool; note engine speed, temp, oil temp/pressure if available
- Check for related cam/crank correlation codes (P0016, P0021, etc.)
- Visually inspect wiring and connectors at the Bank 2 actuator for damage, corrosion, or looseness
- Check relevant fuses and relays for the timing/PCM circuits
- Backprobe the actuator connector while commanding the actuator with a scan tool to confirm presence/absence of control signal
- Measure actuator coil resistance with harness disconnected
Signal parameters
- Typical actuator coil resistance: often ~6–40 ohms (manufacturer-specific) — compare to spec
- Control signal type: PWM (pulse-width modulated) command from PCM; duty cycle 0–100% when commanded
- Expected control voltage: 0–12 V depending on system (many use switched battery + and PCM ground or PCM switched +) — confirm with vehicle manual
- Expected PWM frequency: commonly 30–200 Hz (varies by manufacturer)
- When not commanded: circuit may read battery voltage or ~0 V depending on circuit design; open circuit will show infinite resistance
Diagnostic algorithm
- Connect a competent scan tool and confirm P0020 is current or stored; clear code and attempt to re-run to verify reproducibility.
- Visually inspect Bank 2 cam actuator connector and wiring harness for chafing, pin damage, corrosion, or signs of oil contamination.
- Check related fuses and relays; replace if faulty.
- With ignition ON (engine OFF) measure voltage at actuator connector power terminal and ground terminal. Compare to battery voltage and expected ground reference.
- Disconnect the actuator and measure coil resistance (ohmmeter) between its terminals. If open (infinite) or out of spec, replace actuator.
- Backprobe the control lead while commanding the actuator ON/OFF with the scan tool or using a lab bench PWM generator (engine OFF) to verify PCM output and actuator response.
- If no command signal from PCM but wiring is intact, check continuity from PCM pin to actuator connector. Repair any open/shorts in harness.
- Inspect oil level/condition; if oil is low, dirty, or wrong viscosity, service oil and filter then retest. Some systems require proper oil pressure to move phasers.
- If wiring, connector and actuator are good but no control from PCM, test PCM driver output circuit and grounds. If PCM output is faulty, consider PCM replacement or repair.
- After repair, clear codes and perform camshaft adaptation/relearn procedure if required by manufacturer; road test and re-scan.
- If intermittent, perform wiggle tests and consider using a scope to capture transient signals; consult vehicle-specific service information for exact test values and pinouts.
Likely causes
- Damaged wiring or connector to the Bank 2 actuator (most common)
- Failed actuator/solenoid (stuck open or open coil)
- Corroded connector pins or water ingress at connector
- Blown related fuse or bad ground
- PCM driver fault (less common)
Fault status
Status
Camshaft Position Actuator A Control Circuit/Open — Bank 2. PCM detected an open/high-resistance condition preventing control of the Bank 2 camshaft timing actuator.
Repair difficulty: Medium
Diagnostic time: 1-3 hours
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