DTC 51

Code 51:

CIRCUIT DESCRIPTION:

The A/C amplifier supplies a signal to the ECM when A/C is selected. This signal allows the ECM to adjust engine speed to compensate for the additional load on the engine. Code 51 will set if this signal is not present.

TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. This step determines that a signal is being sent from the A/C switch.

2. This step determines that the A/C amplifier is sending a signal to the ECM.