P2535
Ignition Switch Run/Start Position Circuit High
- Severity
- High
- Driving
- Drivable — book it in
The ignition switch run/start position circuit is reading high - typically shorted to voltage, or contacts stuck closed. The module sees the run/start position selected regardless of where the key actually is, so systems may stay powered when the car is switched off - which flattens the battery overnight.
Possible causes
- CommonIgnition switch contacts stuck or welded closed
- CommonWiring shorted to voltage
- CommonCorrosion in a connector bridging adjacent pins
- PossibleAftermarket alarm or remote start holding the circuit live
- RareFailed control module input
What you might notice
- Battery flat after standing overnight
- Accessories staying on after the key is removed
- Cooling fan or blower continuing to run
- Engine continuing to run briefly after switch-off
- Check engine light on
What to check, in order
- Watch the run/start position state with the key removed. A reading that still shows the position selected confirms the fault immediately.
- Unplug the switch and check whether the high reading persists at the harness.
- Inspect the connector for corrosion bridging adjacent pins.
- Ask whether an aftermarket alarm or remote start was fitted.
- If the battery is going flat overnight, this is the likely cause and worth fixing before replacing the battery.
Read this code from your own car
Plug an ELM327 adapter into the OBD-II port under the dashboard. Pin16 reads every stored, pending and permanent code, explains each one like this page does — offline, with no account — and shows what the car recorded when the fault was set.
Where this code sits
P00xxP01xxP02xxP03xxP04xxP05xxP06xxP07xxP08xxP09xxP0AxxP0BxxP0CxxP0DxxP0ExxP0FxxP10xxP11xxP12xxP13xxP14xxP15xxP16xxP17xxP18xxP19xxP1AxxP1BxxP1CxxP1DxxP1ExxP1FxxP20xxP21xxP22xxP23xxP24xxP25xxP26xxP27xxP28xxP29xxP2AxxP2BxxP2CxxP2DxxP2ExxP2FxxP30xxP31xxP32xxP33xxP34xxP35xxP36xxP37xxP38xxP39xxP3AxxP3BxxP3CxxP3DxxP3ExxP3Fxx
Vehicle speed control, idle control and auxiliary inputs
P2500P2501P2502P2503P2504P2505P2506P2507P2508P2509P2510P2511P2512P2513P2514P2515P2516P2517P2518P2519P2520P2521P2522P2523P2524P2525P2526P2527P2528P2529P2530P2531P2532P2533P2534P2535P2536P2537P2538P2539P2540P2541P2542P2543P2544P2545P2546P2547P2548P2549P2550P2551P2552P2553P2554P2555P2556P2557P2558P2559P2560P2561P2562P2563P2564P2565P2566P2567P2568P2569P2570P2571P2572P2573P2574P2575P2576P2577