P25DE

Code

Generic P — Powertrain

A Camshaft Position - Unable to Achieve Locked Position Bank 1

Brand: Generic

Type: P — Powertrain

Views: UK: 25 EN: 53 RU: 27

AI status

Completed

ready

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Page language: EN

Causes

Faulty VVT/camshaft phaser or actuator (mechanical wear or seizure)
Stuck or faulty camshaft oil control valve (OCV) / solenoid
Low engine oil level, degraded oil, or oil contamination affecting VVT operation
Restricted oil passages or clogged oil filter
Wiring fault, connector corrosion or PCM driver failure for the OCV/actuator
Timing chain/belt stretch, jump, or failed timing components preventing lock

Symptoms

MIL (Check Engine Light) illuminated
Reduced engine power and poor throttle response
Rough idle, stumbling or intermittent misfire
Reduced fuel economy and increased emissions
Unusual noise from timing cover area (rattle or clatter)
Hard starting or stalling in severe cases

What to check

Read freeze-frame and complete DTC list; note engine speed and temperature when fault set
Check for related codes (cam/crank correlation, OCV circuits, oil pressure codes)
Visual inspection: oil level, oil quality, leaks; inspect connectors and wiring to OCV/actuator and cam/crank sensors
Scan-tool: monitor commanded vs actual camshaft angle, OCV duty cycle, and oil control commands in real time
Check resistance and continuity of OCV/actuator solenoid and inspect connector pins for corrosion or damage
Verify engine oil pressure (static and at idle) and inspect oil passages if accessible

Signal parameters

Target camshaft angle/position vs actual camshaft angle (degrees) — actual should follow target within specified tolerance
OCV/actuator commanded duty cycle or on/off command from PCM (percentage or switching)
OCV/actuator coil resistance (ohms) and continuity
Camshaft position sensor signal (voltage/frequency) and crankshaft position correlation
Engine speed (RPM) when lock attempt occurs
Oil pressure and evidence of oil control at the phaser (change in cam angle when OCV actuated)

Diagnostic algorithm

Verify and record the operating conditions when the code set (engine temperature, RPM). Clear the code and attempt to reproduce while monitoring live data.
Check engine oil: level, quality and correct viscosity. If oil is very dirty or low, change oil and filter then retest.
Inspect wiring and connectors for the OCV/actuator and cam/crank sensors. Repair any damage and verify connector seating.
Using a scan tool, monitor commanded cam angle and actual cam angle while commanding the OCV (or during varying RPM/load). Note if actual follows commands.
Test OCV/actuator electrical function: measure coil resistance, energize while monitoring movement (follow safe manufacturer procedure). Replace if out of specification or non-responsive.
If OCV and wiring are functional but cam will not lock, inspect phaser mechanically: remove timing cover or use manufacturer procedure to check phaser pin/lock condition and timing chain/belt condition.
Perform a cam/crank correlation check (cam vs crank timing). If timing has jumped, repair timing chain/belt and associated guides/tensioners.
If mechanical phaser damage or internal engine timing damage is found, repair or replace the phaser, chain/belt, or internal components as required.
After repairs, clear codes and perform a road/drive cycle and recheck for proper cam angle response and that the code does not return. Relearn procedures may be required by manufacturer.
If electrical and mechanical checks are inconclusive, consider PCM/ECM output driver tests or software updates per manufacturer guidance.

Likely causes

OCV/solenoid failure or electrical fault
Insufficient oil pressure or dirty oil preventing phaser actuation
Seized or mechanically damaged cam phaser/actuator
Timing chain/slack or related mechanical timing fault

Fault status

⚠️ Status

PCM set a fault because the A-camshaft on Bank 1 did not reach or maintain the commanded locked position; MIL is illuminated. The condition indicates a VVT actuator/phaser or control problem that can affect timing and engine performance.

🔴 Repair difficulty: Hard

⏱️ Diagnostic time: 2-8 hours