P1257 OBD Trouble Code

1 result found

P1257 - GM
Type	Powertrain - Manufacturer Controlled DTC - Manufacturer Controlled
Description	Supercharger System Overboost Fault Conditions
Cause	Engine running, IAT sensor input more than 14°F, then the PCM detected that the engine torque was above a maximum threshold value (value vanes by commanded gear and rpm) for 6 seconds