Failure Conditions

WARNING: This page is about a different car, the 1995 Cadillac Eldorado. However, it is still accessible from the selected car via links, so may be relevant.

Spark value of 0.3 degrees (VIN Y) or 3 degrees (VIN 9) will increment until a maximum of 21 degrees is reached. If knock is not detected for one second at maximum spark, Code P131 will set.

NOTE: Test numbers refer to numbers on diagnostic chart.

Checks if Code P132 was set due to circuit problem.
Checks knock sensor's ability to detect an induced spark.

Fig 1: Code P131 Schematic, Active Knock Sensor Failure

Courtesy of GENERAL MOTORS CORP.

Fig 2: Code P131 Diagnostic Flow Chart, Active Knock Sensor Failure

Courtesy of GENERAL MOTORS CORP.