Test 1A - Identifying Vehicle Communication Problems
Connect scan tool to Data Link Connector (DLC) to retrieve messages. If scan tool message is blank, see NO RESPONSE DIAGNOSIS table and proceed to appropriate test number. Disconnect scan tool. Ensure ground circuit has continuity at DLC terminals No. 4 and No. 5. Ensure 12 volts is present at DLC terminal No. 16. Try another scan tool and/or cable. See NO RESPONSE DIAGNOSIS, BUS FAULT MESSAGES and BUS SYMPTOMS tables and proceed to appropriate test number.
NO RESPONSE DIAGNOSIS
| Problem Module | Test No. | ||
|---|---|---|---|
| Air Bag Control Module (ACM) | TEST 2A | ||
| Automatic Temperature Control (ATC) | TEST 3A | ||
| Body Control Module (BCM) (1) | TEST 4A | ||
| Anti-Lock Brake Module | TEST 5A | ||
| Mechanical Instrument Cluster (MIC) | TEST 6A | ||
| Overhead Traveler Information Center (OTIS) | TEST 7A | ||
| Powertrain Control Module (PCM) | TEST 8A | ||
| Radio | TEST 9A | ||
| Transmission Control Module (TCM) | TEST 10A | ||
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BUS FAULT MESSAGES
| Fault Messages | Test No. |
|---|---|
| BUS SHORT TO BATTERY | TEST 11A |
| BUS SHORT TO GROUND | TEST 12A |
BUS SYMPTOMS
| Symptom Messages | Test No. |
|---|---|
| Odometer Displays NO BUS | TEST 13A |
| No Fused Ignition Switch Output To BCM | TEST 14A |