Test 1A - Identifying Vehicle Communication Problems
Battery must be fully charged before proceeding. Connect scan tool to Data Link Connector (DLC) to retrieve messages. Ensure ground circuit has continuity at terminal No. 4 on DLC. Ensure 12 volts exists at terminal No. 16 on DLC. See BUS FAULT MESSAGES table and proceed to appropriate test number. If NO RESPONSE message is displayed, see NO RESPONSE DIAGNOSIS table and proceed to appropriate test number.
BUS FAULT MESSAGES
| Fault Messages | Test No. |
|---|---|
| BUS SHORT TO BATTERY | 4A |
| BUS SHORT TO 5 VOLTS | 5A |
| BUS SHORT TO GROUND | 6A |
| BUS (+) & BUS (-) SHORTED TOGETHER | 7A |
| NO TERMINATION | 8A |
| BUS BIAS LEVEL TOO LOW | 9A |
| BUS BIAS LEVEL TOO HIGH | 9A |
| NOT RECEIVING BUS MESSAGES CORRECTLY | 10A |
| NO BUS BIAS | 11A |
| BUS (+) OPEN | 12A |
| BUS (-) OPEN | 12A |
| BUS (+) &/OR BUS (-) OPEN | 12A |
NO RESPONSE DIAGNOSIS
| Problem Module | Test No. | ||
|---|---|---|---|
| Air Bag Control Module | 2A | ||
| Instrument Cluster | (1) | ||
| Powertrain Control Module | 3A | ||
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