What does code P25B8 mean?

Q: What does code P25B8 mean?

Auxiliary Ignition Switch On/Start Position Circuit Low. P25B8 indicates that the auxiliary ignition switch on/start position circuit has a low voltage condition, meaning the control module sees the circuit voltage below the expected threshold when the switch is in the on or start position. The computer detects this by monitoring the voltage on the signal circuit and flagging a fault when it remains too low for a calibrated time.

DTC codes / P25xx · Vehicle speed, idle control and auxiliary inputs / P25B8

P25B8Auxiliary Ignition Switch On/Start Position Circuit Low

P25B8 indicates that the auxiliary ignition switch on/start position circuit has a low voltage condition, meaning the control module sees the circuit voltage below the expected threshold when the switch is in the on or start position. The computer detects this by monitoring the voltage on the signal circuit and flagging a fault when it remains too low for a calibrated time.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaVehicle speed, idle control and auxiliary inputs

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.