Engine Control Module: Testing and Inspection

PCM Power Supply, MIL & DLC Connector Circuits Diagram:

Enter Diagnostic Mode:
To enter diagnostic mode, ground pin 12 of the Data Link Connector (DLC) and turn the ignition switch "ON".

^ If the A/C fuse is blown, the CCM will not receive IGN 3 power and will not enter diagnostic mode. This condition should also set code 16.

The CCM will display any diagnostic trouble codes and the module for which they apply in an automatic code display sequence. The CCM is Module 1, the PCM is module 4 and ABS/ASR EBTCM is module 9, and the DERM is module "A". During automatic display sequence, each code is displayed for three seconds, followed by a one second pause before the next code is displayed. There is a 3 second pause between the code display sequence for different modules. The end of the code list for each module is indicated by "---" being displayed in the speedometer. If there is a communications problem between the PCM or EBTCM and the CCM, the speedometer will display "ERR" when the CCM is trying to communicate with the PCM or EBTCM.

CCM Diagnostic Display (Automatic Mode Display):

Specific Module Interrogation:
The particular module being interrogated is indicated on the trip monitor, and the codes are displayed on the speedometer. The speedometer also indicates if the trouble code is a current code or a history code with a "C" or "H", respectively. All PCM and EBTCM codes will be displayed by the CCM as history codes, whether they are current or history.

When all diagnostic trouble codes have been displayed for all modules, the trip monitor will display 1.0 and the speedometer will be blank. This indicates Manual Mode and the CCM is awaiting technician instructions.