Code
P25E4
Generic
P — Powertrain
B Camshaft Position - Unable to Achieve Locked Position Bank 1
Views:
UK: 16
EN: 22
RU: 21
AI status
Completed
Completed
100%
Causes
- Low or dirty engine oil causing poor VVT oil control
- Clogged or stuck oil control valve (OCV) / VVT solenoid
- Failed or seized camshaft phaser (variable timing actuator)
- Worn or jumped timing chain/belt or damaged timing components
- Faulty camshaft position sensor or poor sensor signal
- Damaged wiring or connectors to camshaft sensor, OCV, or PCM
Symptoms
- Check Engine Light (MIL) on
- Engine runs rough at idle or unstable idle
- Reduced engine power or hesitation under load
- Poor fuel economy and increased emissions
- Possible unusual engine noise (timing chain noise)
What to check
- Read and record current/return DTCs and freeze frame data
- Check engine oil level and condition (viscosity/contamination)
- Inspect wiring and connectors at camshaft sensor(s), OCV(s), and PCM for corrosion, damage, or looseness
- Visually inspect timing chain/belt and phaser (if accessible) for wear or damage
- Check for related codes (crank/cam correlation, oil pressure faults, other VVT codes)
- Check TSBs and PCM software updates for this code/model
Signal parameters
- Camshaft position sensor signal: typical square-wave 0–5V (or 0.2–4.8V for some sensors); frequency varies with engine RPM
- Target camshaft angle vs actual camshaft angle: expected lock/step change within manufacturer tolerance (typically a few degrees)
- OCV (VVT solenoid) commanded duty cycle or % open vs actual response
- Engine oil pressure at idle: should be within manufacturer spec (often >100–200 kPa depending on engine)
- Engine speed range for tests: idle to >2000 rpm to observe dynamic behavior
Diagnostic algorithm
- Connect scan tool, record freeze frame and live data for camshaft position (Bank 1 B), commanded vs actual angle, OCV duty, oil pressure and RPM
- Verify DTCs: note any related cam/crank correlation or oil pressure codes; clear codes and re-check to confirm repeat
- Check engine oil level and condition; if low or old/contaminated, correct and re-test after cycle
- Visually inspect connectors and wiring for Bank 1 cam sensor and OCV; repair any damaged wiring or poor terminals
- Command OCV/OCVs with scan tool while observing duty cycle and cam angle response; verify solenoid energizes and cam angle moves accordingly
- If OCV does not respond electrically, test solenoid resistance and supply voltage; repair/replace as needed
- If OCV responds electrically but cam does not follow, suspect phaser/mechanical fault — perform mechanical inspection: remove valve cover or use manufacturer procedure to inspect phaser/timing chain condition
- Check camshaft position sensor signal with oscilloscope (or high-quality diagnostic tool) for clean waveform and correct timing relative to crank signal; replace sensor if signal is missing or noisy
- If timing chain has jumped or phaser is seized/worn, repair timing components (chain, guides, tensioner, phaser) and reassemble to factory timing, then retest
- After repairs, clear codes and perform road test/functional test with scan tool to confirm commanded vs actual cam angle reaches locked position and DTC does not return
- If all mechanical and electrical checks pass but code persists, check PCM software updates and consider PCM reflash or replacement as a last resort
Likely causes
- Clogged or malfunctioning oil control valve (OCV)
- Low oil level or degraded oil (affecting phaser operation)
- Stuck or failed camshaft phaser on Bank 1 cam B
- Wiring/connector fault to OCV or cam position sensor
Fault status
Status
B Camshaft Position - Unable to Achieve Locked Position Bank 1 (VVT/phasor did not reach commanded/locked position)
Repair difficulty: Medium
Diagnostic time: 1.5-3.0 hours
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