P25D1

Code

Generic P — Powertrain

Exhaust Camshaft Actuator Park Lock Control Circuit Low Bank 1

Brand: Generic

Type: P — Powertrain

Views: UK: 21 EN: 27 RU: 23

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Page language: EN

Causes

Open or shorted wiring in the park-lock control circuit (Bank 1)
Corroded, loose, bent or contaminated connector at the actuator or PCM
Park lock actuator (solenoid) internal short or low resistance fault
Faulty PCM driver transistor or internal PCM ground/power issue
Blown fuse or poor battery/ignition power supply to the circuit
Intermittent connection due to heat, vibration or damaged harness

Symptoms

Malfunction Indicator Lamp (MIL) illuminated (check engine light)
Reduced or disabled variable valve timing on exhaust cam (loss of performance)
Engine runs roughly at some speeds or reduced power/acceleration
Poor fuel economy or increased emissions
Possible engine limp mode or stored related camshaft timing codes

What to check

Read freeze frame and related codes with a scan tool; note conditions when code set
Visually inspect wiring and connectors at the exhaust camshaft actuator and PCM for damage, corrosion, or loose pins
Check fuses and battery/ignition power feeding the PCM and actuator circuit
Backprobe the actuator connector while commanding the park-lock with a scan tool to observe voltages
Measure resistance of the actuator solenoid (with connector disconnected) and compare to expected range
Perform wiggle test on harness while monitoring signal for intermittent changes

Signal parameters

Resting (key ON, engine OFF) supply voltage to the actuator harness: ~battery voltage (≈11–13.5 V) when powered circuits are present
Driver output when commanding park-lock: either a switched ground or switched 5–12 V depending on vehicle design (steady DC during command)
Typical solenoid coil resistance (generic): roughly 5–60 ohms — many actuators are in low-ohm range (confirm with OEM spec)
Expected current draw when energized: typically a fraction of an amp up to a few amps depending on actuator (use proper current clamp or bench measurement)

Diagnostic algorithm

Safety first: park vehicle, set parking brake, disconnect battery if directed for repairs. Use proper PPE.
Scan: Read and record P25D1 and any related codes; clear codes and perform a drive/recreate if needed to verify persistence.
Visual: Inspect actuator connector, wiring harness, and PCM connector for damage, corrosion, chafing, or heat exposure.
Power check: With key ON (engine OFF), verify battery voltage at the circuit power feed and at the actuator connector pin(s). Check relevant fuse(s).
Command test: Use a factory scan tool or bi-directional tester to command the exhaust cam park-lock actuator and observe operation; listen for actuation and watch cam timing parameters.
Backprobe/measure: While commanding the actuator, backprobe the control wire(s). Confirm the PCM drives the circuit (voltage swings or ground switching). Note if the circuit is held low when it should be open.
Resistance test: Disconnect actuator and measure coil resistance across actuator terminals. Compare to expected range (if unknown, look for short-to-ground or open).
Continuity/short checks: Check continuity from actuator control pin to PCM pin; check for short to ground or short to battery. Wiggle harness to find intermittent faults.
Swap/bench test: If accessible and identical spare available, swap with a known-good actuator or bench-test the actuator with a controlled power source to confirm function.
PCM check: If wiring and actuator test good, suspect PCM driver. Before replacing PCM, confirm with scope or professional test bench and verify no intermittent wiring faults remain.
Repair: Repair or replace damaged harness, connector, fuse or actuator as needed. Reassemble, clear codes, and test drive to confirm code does not return.

Likely causes

Damaged wiring branch near the cylinder head or valve cover
Failed camshaft park-lock solenoid (stuck or shorted)
Connector corrosion at the actuator or chassis ground point
PCM driver failure or internal electronics fault
Aftermarket service or recent repair disturbed harness or connector

Fault status

⚠️ Status

PCM detected low voltage on Exhaust Camshaft Actuator Park Lock Control circuit (Bank 1). Circuit reads below expected threshold or is shorted to ground, preventing reliable actuator control.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours