Bus +/- Signals Open From Or Blank Screen On OTIS
NOTE:
After making any repairs, perform BODY VERIFICATION TEST
under VERIFICATION TESTS.
- Connect scan tool to Data Link Connector (DLC). Turn ignition on. Using scan tool, attempt to communicate with Body Control Module (BCM). If scan tool communicates with BCM, go to next step. If scan tool does not communicate with BCM, repair communication concern. See NO RESPONSE FROM BODY CONTROL MODULE (BUS +/- SIGNAL OPEN) .
- Turn ignition off. Disconnect Overhead Travel Information System (OTIS) module harness connector. Turn ignition on. Measure voltage at terminal No. 2 (Dark Blue/White wire) at OTIS module harness connector. See Fig 1 . If battery voltage exists, go to next step. If battery voltage does not exist, repair open in Pink wire between junction block and OTIS module.
- Turn ignition off. Measure resistance between ground and terminal No. 3 (Black/Light Green wire) at OTIS module harness connector. If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, repair open in Black/Light Green wire between ground and OTIS module.
- Connect Diagnostic Readout Box (DRBIII(R)) to Data Link Connector (DLC). Connect Scope Input Cable (CH7058) to channel one connector on DRBIII(R). Connect Red and Black leads and Cable Probe Adapter (CH7062) to scope input cable. Using DRBIII(R), access lab scope 12-volt square wave and set to 20-volt range. Go to next step.
- Connect Black lead to ground and Red lead to terminal No. 5 (Violet/Yellow wire) at OTIS module harness connector. Turn ignition on. If voltage does not pulse from zero to 7.5 volts, go to next step. If voltage pluses from zero to 7.5 volts, replace OTIS module.
- Turn ignition off. Disconnect Body Control Module (BCM) from back of junction block. Measure resistance in Violet/Yellow wire between terminal No. 5 at OTIS module harness connector and terminal No. 10 at BCM connector on back of junction block. See Figure and Fig 1 . If resistance is greater than 5 ohms, repair open in Violet/Yellow wire between OTIS module and BCM. If resistance is 5 ohms or less, replace BCM.