P2535
OBD-II Diagnostic Code
Severity: ModerateWhat Does This Error Mean?
P2535 means the ECM detected an issue with the ignition switch's RUN position circuit. The switch may be worn, the wiring may be faulty, or the ignition relay has a problem. The car may stall or have intermittent electrical issues.
Affected Models
- All OBD-II vehicles (1996+)
Common Causes
- Ignition switch worn (common on high-mileage vehicles)
- Wiring to ignition switch damaged
- Ignition relay failing
- ECM input circuit fault
How to Fix It
-
Check if the car stalls or loses power intermittently.
A worn ignition switch can momentarily lose contact, causing the engine to cut out and restart.
-
Wiggle the key while the car is running.
If the dashboard lights flicker or the engine stumbles, the ignition switch contacts are worn.
-
Replace the ignition switch.
The switch is separate from the lock cylinder. On most vehicles it is behind the steering column cover.
Frequently Asked Questions
Is the ignition switch the same as the key cylinder?
No. The key cylinder is the mechanical part you insert the key into. The ignition switch is the electrical component behind it that sends signals to the ECM.
Can a worn ignition switch cause a no-start?
Yes. If the RUN position contact is completely worn, the ECM does not receive power and the engine will not start or will stall immediately.