P132

Circuit Description

This diagnostic test checks for a Knock Sensor wiring problem. The circuitry within the Knock Sensor causes the PCM's supplied 5 volts signal to be pulled down, so that under no knock condition CKT 496 will measure about 2.5 volts. The Knock Sensor produces an A/C signal which rides on the 2.5 volts DC voltage. The amplitude and signal frequency of the A/C signal is dependent upon the knock level.

If CKT 496 becomes open or shorted, the voltage will either go above 4.8 volts or below 0.3 volt. If either of these conditions are met for 0.4 second, Code P132 is set.

Test Condition(s)

1. Coolant Temperature 40°C or greater.
2. Battery voltage 11 volts or greater.

Failure Condition(s)

1. Knock Sensor feedback voltage 4.8 volts or greater.
OR
2. Knock Sensor feedback voltage 0.3 volt or less.

Action Taken

PCM turns 'ON' the 'SERVICE ENGINE SOON' MIL.

Notes on Fault Tree

1. Checking if Code P035 is also set. A REF LO problem can cause other ignition problems.
2. Checking for proper operating voltage of 0.3 to 4.8 volts present at PCM terminal '1A13'.
3. Checking CKT 496 for a short to ground. If circuit OK, knock sensor must be bad.
4. Checking for a short to voltage on CKT 496.
5. Checking CKT 496 for an open.