Entering Diagnostics (Automatic Display Sequence)
- Turn ignition off. Using a jumper wire, ground Assembly Line Diagnostic Link (ALDL) connector terminal "A" to "G". See Fig 1. Turn ignition on. CCM will display fault codes and module for which they apply in an automatic display sequence.
- First digit on trip monitor represents module number; CCM is module "1", ECM is module "4" and ABS/ASR is module "9". During automatic display sequence, fault codes for each module are displayed, each code is displayed for 3 seconds, followed by a one second pause before next code is displayed. There is a 3 second pause between display sequence for each module. End of automatic display sequence is displayed as "- - -" on speedometer.
- If a communications problem is present between ECM or EBCM and CCM, speedometer will display "Err" when CCM is trying to communicate with ECM or EBCM. Speedometer display will also indicate if a fault code is current or history. Current codes are displayed as "C" and history codes are displayed as "H" on speedometer display. All ECM and ABS/ASR codes will be displayed by CCM as history codes, whether codes are current or history.
- After all fault codes have been displayed for each module, trip monitor will display "1.0" and speedometer display will be blank indicating CCM is in manual diagnostic mode waiting for input from technician. At any time during automatic display sequence, press any button on DIC to cancel automatic sequence and enter manual diagnostic mode. To exit diagnostics, turn ignition off and remove jumper wire. See ABS/ASR FAULT CODES table. To clear fault codes, see CLEARING FAULT CODES. If no fault codes are present and a problem exists with ABS/ASR system, see ABS/ASR SYMPTOM DIAGNOSIS.
Courtesy of GENERAL MOTORS CORP.