P2538
Ignition Switch Accessory Position Circuit High
Ignition switch / electrical
Generic OBD-II
Low
What it means
P2538 means the circuit that tells the computer when the ignition switch is in the accessory position is reading higher than expected. It's an electrical fault in the ignition switch or its wiring, not an engine problem. The engine still starts and runs, though accessory-powered features may occasionally misbehave.
Low
Can I keep driving? Safe to drive. The engine starts and runs normally; the fault is in how the computer senses the ignition switch's accessory position.
Common symptoms
What you'll notice
- Check-engine light on
- Accessory-position input read as high by the module
- Occasional glitches in accessory-powered features
- No change in engine starting or running
Common causes
Most likely first
- Ignition switch accessory circuit wiring shorted to voltage or openLikely
- Worn or faulty ignition switch contactsCommon
- Corroded or loose connector at the ignition switchCommon
- Poor ground or high-resistance splice in the accessory circuitLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and confirm the accessory-position input state in live data.
- Inspect the ignition switch connector and wiring for a short to voltage or an open.
- Cycle the key through positions while watching the input change.
- Check the ignition switch contacts and grounds for wear or corrosion.
- Repair wiring or replace the ignition switch as needed, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with P2538?+
Yes. This monitors the ignition switch's accessory position and doesn't stop the engine from starting or running.
Can I just clear P2538?+
It returns until the switch or wiring fault is repaired. Find the high-reading cause first.
Related codes
Often seen with P2538
Read & clear P2538 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX