I037

CIRCUIT DESCRIPTION

Code I037 will set if the ignition is on and the IPC is not able to exchange data with the ACP. If any other communication codes are stored along with I037, see the chart "MULTIPLE INTERMITTENT CODES". When this is the only communication code stored, the problem must be one of the following:

^ An open in the 800 circuit between the ACP and PCM and a second open in the 800 circuit between the ACP and Diagnostic Energy Reserve Module (DERM) (4.9L) or RTD (4.6L) and ACP.

^ An open in ACP power or ground circuits.

^ A faulty ACP.

During the time the failure is present, the climate control panel will display "--" for outside and set temperatures, defrost mode will be selected, the A/C clutch will be disabled, and the blower will run at a constant 6 volts.

TEST DESCRIPTION

Test numbers refer to circled numbers on the diagnostic chart.

1. Cavity "C11" is the serial data line to the IPC. Under normal operation the voltage on this line will appear as 3 to 5 volts and be constantly fluctuating. If this is not the case, the most likely cause is an open in CKT 800 between the ACP and the PCM.

2. Before replacing the ACP it is important to ensure no connector damage or loose terminals are causing intermittent contacts.

NOTES ON INTERMITTENTS

If only Code I037 is stored as "History", check ACP power (Cavities "C12", "C13"), ground (Cavity "C1"), and serial data (Cavities "C10", "C11") for intermittent open circuits.