P25B7Auxiliary Ignition Switch On/Start Position Circuit
- Generic OBD-II code · Powertrain
- How the car detects it
- P25B7 covers the hard-wired input from an auxiliary ignition switch that commands the On and Start positions from a second location, for example a rear panel behind the cab, a work platform or a remote station on a chassis-cab truck. The module flags a state on this line it cannot interpret, such as an open circuit, without saying whether the level is too low or too high. No manufacturer documents P25B7 publicly. The nearest published logic is the main run/crank input, for which the GM brake control module in table 25OBDG04A sets P2534 when its wake-up line stays low for 3 s while the ECM reports run or crank. Navistar describes remote start and shutdown panels for PTO bodies built on this principle. For the driver, the remote start point may stop responding while the key in the cab still works.
- What you may notice
- Engine cannot be started or switched on from the auxiliary position
- Normal key or push-button start still works
- Stored code, often without other complaints
- Likely causes
- LikelyOpen wire or loose connector in the harness to the body or remote panel
- PossibleWorn or corroded contacts in the auxiliary switch
- PossibleFaulty or modified upfitter wiring
- RareInput stage of the reading module damaged
- Repair
- Medium · Usually a job for a workshop.Typical cost: €80 – €450
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.