| DTC Data Sheet | |
| System | Powertrain |
| Standard | SAE J2012 / ISO 15031-6 |
| Fault type | Performance |
| Official meaning | A Camshaft Position – Timing Over-Retarded (Bank 1) |
Bank 1 intake VVT cam timing is more retarded than commanded — the cam is failing to advance to the position the PCM is requesting. Mirror condition to P0011.
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P0012 Quick Answer
Bank 1 intake VVT cam timing is more retarded than commanded — the cam is failing to advance to the position the PCM is requesting. Mirror condition to P0011. The first thing to check is engine oil level, condition, and viscosity — many P001-range faults are oil-driven before they are electrical.
What Does P0012 Mean?
A Camshaft Position – Timing Over-Retarded (Bank 1). Bank 1 intake VVT cam timing is more retarded than commanded — the cam is failing to advance to the position the PCM is requesting. Mirror condition to P0011.
Symptoms
- Check engine light
- Rough idle or unstable idle speed
- Sluggish acceleration, especially at low rpm
- Reduced fuel economy
- Cam phaser rattle on cold start (phaser unable to lock to default position)
Common Causes
- Low oil pressure to the VVT actuator (worn oil pump, low level, or wrong viscosity)
- Stuck-closed or partially-blocked VVT solenoid
- Sludge or debris in the cam phaser preventing advance
- Stretched timing chain (mechanical retardation that the phaser cannot overcome)
- Failed VVT actuator unable to advance under hydraulic pressure
- Wiring fault preventing the solenoid from being commanded fully on
Diagnosis Steps
You’ll need a scan tool capable of reading live powertrain data, a digital multimeter, and access to the wiring diagram for the specific platform.
- Confirm oil level and viscosity first; low pressure is the dominant cause.
- Read live data — commanded cam phase will be high (advance demand) and actual will lag, exceeding the calibrated retard threshold.
- Inspect VVT solenoid and screen — clean or replace if contaminated.
- Measure oil pressure at the VVT supply gallery if a port is available, or perform a dry/wet oil pressure test.
- Check timing chain stretch using OEM chain-stretch-monitor data if exposed by the scan tool.
Possible Fixes
- VVT solenoid replacement + screen cleaning
- Oil and filter change
- Timing chain kit on stretched-chain platforms
- Oil pump replacement when supply pressure is the root cause
Can I Still Drive With P0012?
The vehicle will usually still drive with P0012 stored, but performance and fuel economy are degraded. The fault disables or limits the affected actuator, and the PCM may inhibit emissions monitors. Drive to a workshop, but don’t ignore the code long-term — VVT and EVAP failures often cascade into related faults if left untreated.
How Serious Is This Code?
P0012 is a moderate-priority fault. It will not prevent the engine from running but will affect drivability, emissions, and over time can damage related components (cam phaser wear, catalytic converter on EVAP-related codes). Address within a few drive cycles.
FAQ
Will P0012 clear itself?
Only if the underlying fault was intermittent and self-corrected. Most P0012 root causes (failed solenoid, wiring damage, blocked screen) are persistent and require physical repair.
Can I clear P0012 without fixing it?
You can clear it with a scan tool, but it will return as soon as the fault condition reappears — typically within one or two drive cycles.
Is P0012 related to other codes?
Often, yes. Cam-position and EVAP faults frequently set adjacent codes — if P0012 is present, scan for related codes in the same range and address them as a group rather than one at a time.