P2535 code meaning
Ignition Switch On/Start Position Circuit High
Powertrain system Generic code P25xx codes Check engine light
What P2535 means
P2535 means the run/crank input stays active while it should be off. GM's 2025 tables fail it in the TCM after 320 of 400 samples with run/crank true while the ECM reports it inactive, Type A, and in the brake control module (EBCM) when the primary wakeup line stays high for 3 s against the network status, Type B; the 2016 Volt uses more than 6.0 V on the line with run/crank inactive. GM bulletin PIT6396 describes a concrete backfeed: once a new K111 fuel pump driver module goes into 2020–2023 Silverado/Sierra with the 3.0L or 6.6L diesel, about 2 V return on ignition circuit 439 via the wiring of the sensor that detects water in the fuel once the key is off. Ram also lists P2535 for the 2021 1500 eTorque. Ford's BOSS 302S table shows no MIL marker.
P2535 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2535
- MIL on, code returns at every key-on after clearing
- Modules stay awake, battery drain
Common causes of P2535
- Most likelyVoltage backfeed from another module (GM K111 fuel pump driver via water-in-fuel sensor circuit)
- PossibleRun/crank relay stuck closed
- PossibleRun/crank wire touching a battery feed
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Ignition switchWiring harness
What each part of P2535 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 5 | Area: vehicle speed, idle control and auxiliary inputs. |
| 35 | The exact fault in that area. |
What to do next
- Note P2535 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2535
What does P2535 mean?
P2535 means "Ignition Switch On/Start Position Circuit High". P2535 means the run/crank input stays active while it should be off. It is a generic code, so it means the same on every make.
Is it safe to drive with P2535?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P2535 fail an emissions test?
Yes, it can. P2535 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P2535 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P2535 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.