P25CB code meaning
Intake Camshaft Actuator Park Lock Control Circuit Low (Bank 1)
Powertrain system Generic code P25xx codes Check engine light
What P25CB means
P25CB points to a control line for the intake phaser lock on bank 1 that reads lower than it should, most often a short to ground on the wire or inside the lock solenoid. Depending on how the driver is wired, the solenoid may then stay energised or never receive current, so the lock pin is either released all the time or cannot be pulled back. Released permanently, the phaser can rattle at start before oil pressure arrives; stuck in, it keeps the intake cam at its base timing. GM's 2015 Volt and ELR OBD table 15OBDG01 places P25CB in the intake phaser fault bundles that pause the related phaser checks, without listing a threshold. CARB requires circuit checks on such output components. Low voltage events can set several lock codes together.
P25CB at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P25CB
- Check engine lamp on
- Brief rattle from the timing drive at start
- Reduced power with fixed intake timing
Common causes of P25CB
- Most likelyLock control wire shorted to ground
- PossibleInternal short in the lock solenoid
- Less likelyWeak battery or voltage dip during cranking
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Intake cam phaser b1Park lock solenoidWiring harness
What each part of P25CB means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 5 | Area: vehicle speed, idle control and auxiliary inputs. |
| CB | The exact fault in that area. |
What to do next
- Note P25CB and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P25CB
What does P25CB mean?
P25CB means "Intake Camshaft Actuator Park Lock Control Circuit Low (Bank 1)". P25CB points to a control line for the intake phaser lock on bank 1 that reads lower than it should, most often a short to ground on the wire or inside the lock solenoid. It is a generic code, so it means the same on every make.
Is it safe to drive with P25CB?
Drive gently and only to a workshop. With P25CB the car can go into limp mode (reduced power) to protect itself.
Will P25CB fail an emissions test?
Yes, it can. P25CB is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P25CB to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P25CB clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.