Charging System Test No 1 - Charging System Code Check

Connect diagnostic read-out box to diagnostic connector in engine compartment. Turn ignition on, off, on, off, on within 5 seconds. Record all codes. Erase fault codes. See ERASING CODES FROM SMEC MEMORY in this article. Start engine and allow to idle for 7 minutes. Raise engine speed to 1500 RPM for 30 seconds. Stop engine. Put system in Diagnostic Test Mode. Refer to ENTERING ON-BOARD DIAGNOSTICS . Record all codes.

Fig 1: DRB-II Tester (C-4805)
If same code(s) were stored before and after memory was cleared, problem still exists. If a code does not reappear after engine is started, problem no longer exists, but was intermittent. Go to next step. If code 88-12-55 is stored (no codes stored), go to CHARGING SYSTEM TEST NO 2 . If code 88-11-12-16-55 is stored (battery voltage sense), go to CHARGING SYSTEM TEST NO 3 . If codes 88-12-41-46-55 or 88-12-46-55 are stored (alternator output too high), go to CHARGING SYSTEM TEST NO 4 . If codes 88-12-41-55, 88-12-41-47-55, or 88-12-47-55 are stored (alternator output too low), go to CHARGING SYSTEM TEST NO 5 .
The majority of intermittent failures are caused by wiring and connections. The only way to locate them is to try to duplicate the problem. Because the SMEC can remember where the fault is located, the ATM and Sensor Tests can be used to try to locate the intermittent failure.
If a fault code 41 does not reappear, enter ATM Test "09". Refer to ENTERING ON-BOARD DIAGNOSTICS in this article. Connect an analog voltmeter to the field control wire terminal of alternator and watch pulsations on meter. Wiggle all connectors and wires in the circuit. When the bad connection or wire is located, the ATM test will be interrupted.
If fault code 16 does not reappear, enter Sensor Test "07". Refer to ENTERING ON-BOARD DIAGNOSTICS in this article. Wiggle all connectors and wires in the circuit. When the bad connection or wire is located, the display on tester will change.