Some cam phasers carry a locking pin that holds the rotor in a fixed base or middle position for starting and while oil pressure is still building. Where that pin is released and engaged by its own solenoid, the controller supervises this extra circuit. P25CA reports that the lock control circuit for the intake phaser on bank 1 is open or otherwise not behaving electrically, so the lock can no longer be operated on command. GM's 2015 Volt and ELR table 15OBDG01 lists P25CA among the intake phaser fault groups that suspend the other cam phaser diagnostics; it gives no thresholds of its own. Passive designs such as BorgWarner's mid-position lock for Hyundai lack this circuit. Expect rough starts or idle and limited cam timing.
Medium severity. Can I keep driving?Drive little and gently. If you hear timing chain noise or the oil light comes on, shut off the engine.
Bank 1 is the side of the engine with cylinder 1. Inline engines only have this bank.
Symptoms
- Check engine lamp on
- Rough start or unsteady idle
- Intake cam timing held at a default position, less power
Most likely causes
- Open winding in the intake phaser lock solenoid
- Connector off or terminal pushed back after engine work
- Broken wire between module and lock solenoid
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It can trigger limp mode.
- It affects emissions.
What each character of P25CA means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- 5: Speed and idle
- CA: Specific fault in that system
Frequently asked questions
Can I keep driving with code P25CA?
Drive little and gently. If you hear timing chain noise or the oil light comes on, shut off the engine.
What causes code P25CA?
The most common causes are: open winding in the intake phaser lock solenoid; connector off or terminal pushed back after engine work; broken wire between module and lock solenoid.
Related codes
- P25CBIntake Camshaft Actuator Park Lock Control Circuit Low (Bank 1)
- P25CCIntake Camshaft Actuator Park Lock Control Circuit High (Bank 1)
- P25CDIntake Camshaft Actuator Park Lock Control Circuit/Open (Bank 2)
- P25D0Exhaust Camshaft Actuator Park Lock Control Circuit/Open (Bank 1)
- P25DD"A" Camshaft Position - Stuck In Locked Position (Bank 1)
- P25DE"A" Camshaft Position - Unable to Achieve Locked Position (Bank 1)
- P0010"A" Camshaft Position Actuator Circuit (Bank 1)
Sources
- gsi.ext.gm.com: 15OBDG01 Hybrid Diagnostics
- borgwarner.com: borgwarner s vct technology with mid position lock
- law.cornell.edu: 13 CCR 1968.2
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.