I034

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

Code I034 will set if the ignition is on and the IPC is not able to exchange data with the PCM. If any other communication codes are stored along with I034, see the chart "Multiple Intermittent Codes". Multiple Data Communication 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 IPC and PCM and a second open in the 800 CKT between the PCM and Air Conditioning Programmer (ACP).

^ An open in PCM power or ground circuits (will also result in code P052 and driveability conditions).

^ A faulty PCM or PCM Calpak.

During the time the failure is present, coolant temperature will be displayed as "--" if selected on the DIC, the fuel data panel displays will read "--", the cooling fans will be commanded to high speed, and no PCM diagnostic information will be available for display. Also, the DIC will display "LOW OIL PRESSURE - STOP ENGINE" at key "On" with engine not running.

TEST DESCRIPTION

Test numbers refer to circled numbers on the diagnostic chart.

1. I034 can indicate either a PCM problem or a communications problem. A no start or driveability symptom indicates a PCM related problem, diagnosed in POWERTRAIN MANAGEMENT. Powertrain Management

2. Cavity "2A8" 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 IPC and the PCM.

3. If P052 is stored as history, the problem is an intermittent PCM power or ground. Refer to P052 for diagnosis.

4. The communication line CKT 800 to the PCM is operating normally. It is important to ensure no connector damage or loose terminals are causing intermittent contacts. Also the PCM calpak should be checked for proper insertion. If all checks are OK, the PCM is suspected.

NOTES ON INTERMITTENTS

If only Code I034 is stored as "History", check a the 800 circuit for an intermittent open circuit between the PCM and IPC. If PCM code P052 history is also set, power and ground is suspected. Refer to COMPUTERS AND CONTROL SYSTEMS for P052 diagnosis. Computers and Control Systems