Scan Tool Cannot Communicate With Class 2 Device
WARNING: This page is about a different car, the 1999 Pontiac Grand Am and 1999 Oldsmobile Alero. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
To identify wire colors and modules on serial data line, see appropriate wiring diagram in
DATA LINK CONNECTORS article in WIRING DIAGRAMS.
- Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - GASOLINE - EXCEPT METRO, PRIZM & TRACKER article in ENGINE PERFORMANCE. Go to next step.
- Turn ignition on. Observe Malfunction Indicator Light (MIL). If MIL comes on, go to next step. If MIL does not come on, go to MIL INOPERATIVE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - GASOLINE - EXCEPT METRO, PRIZM & TRACKER article in ENGINE PERFORMANCE.
- Connect scan tool to DLC. If scan tool powers up, go to next step. If scan tool does not power up, go to step 6 .
- Attempt to establish communications with BCM and EBCM. If scan tool communicates with modules, go to step 6 . If scan tool does not communicate with modules, go to next step.
- Turn ignition off and disconnect PCM connectors. Turn ignition on. Attempt to establish communications with BCM and EBCM. If scan tool communicates with modules, go to DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK . If scan tool does not communicate with modules, go to next step.
- Check for open or poor connections in class 2 serial data line between splice and PCM (Purple wire). If faulty circuit was found and repaired, go to DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK . If circuit is okay, go to next step.
- Start engine and allow to idle until normal operating temperature is reached. Check for any DTCs. If scan tool shows DTCs are set that have not been addressed, go to appropriate DTC table under appropriate system. If scan tool shows DTCs are set that have been addressed and/or repaired, go to DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK .