Ignition Switch Run/Start Position Circuit High
The P2535 code indicates that the Powertrain Control Module (PCM) has detected a voltage signal from the ignition switch's run/start position circuit that is higher than the expected range. This typically points to a short to voltage, a faulty ignition switch, or a wiring issue. The ignition switch sends a signal to the PCM to indicate when the key is in the run or start position; an abnormally high voltage can cause the PCM to misinterpret the ignition state, potentially leading to starting or drivability problems.
1. Most Common Causes
- Faulty ignition switch (key) with internal short to battery voltage
- Run/Start signal circuit wiring shorted to 12V (damaged insulation, chafing)
- Damaged ignition switch connector or pins shorted together
- Body Control Module (BCM) or PCM failure (rare, internal driver/pull-down fault)
- Incorrect aftermarket accessory installation (alarm, remote start) bridging the circuit
2. Symptoms You Will Notice
- Engine may not start or stalls unexpectedly
- Check Engine Light illuminated
- Intermittent starting issues
- Electrical accessories may behave erratically
3. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm the P2535 code and check for any related codes.
Step 2: Visually inspect the ignition switch wiring and connectors for damage, corrosion, or loose connections.
Step 3: Test the ignition switch voltage at the PCM connector using a multimeter; compare with manufacturer specifications.
Step 4: If voltage is high, isolate the circuit to find the short to voltage; repair or replace affected wiring.
Step 5: If wiring is intact, replace the ignition switch and clear the code.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with this code as it can cause unexpected stalling or starting failure, which may be dangerous.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for parts and labor, depending on the exact cause and vehicle model.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.