P2535 critical

Ignition Switch Run/Start Position Circuit

The P2535 code means the vehicle's onboard diagnostic system has detected: Ignition Switch Run/Start Position Circuit. This is a critical severity code.

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Keep driving?: No -- stop driving
DIY difficulty: hard
Estimated cost: $150 - $700 (parts and labor)

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Common Symptoms

Engine will not crank
No response when turning key to start
Dashboard lights come on but starter does not engage
Push button start not functioning

Probable Causes (Ranked by Likelihood)

Failed ignition switch start position contacts Very High
Faulty starter relay driven by ignition circuit High
Neutral safety switch preventing start signal Moderate
ECM not receiving start/run transition signal Low

Step-by-Step Diagnostic Procedure

Test voltage at ignition switch start terminal during cranking attempt
Check starter relay operation
Verify neutral safety switch operation in park and neutral
Confirm ECM receives both run and start signals

Frequently Asked Questions

Why won't my engine crank with P2535?

The ECM is not receiving the proper signal indicating the ignition switch has moved from run to start position, so it does not command the starter relay to engage.

Is this related to the neutral safety switch?

It can be. The neutral safety switch is in the start circuit path on many vehicles. If it fails, the start signal cannot reach the ECM or starter relay.

Does P2535 affect push-button start vehicles?

Yes. Push-button vehicles still have an electronic ignition switch circuit. P2535 can set if the start button signal is not properly reaching the ECM.