DTC U1016: Loss Of Class 2 Communication With Pcm: Testing
WARNING: This page is about a different car, the 1999 Buick Regal and 1999 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
- If BCM diagnostic system check was performed, go to next step. If BCM diagnostic system check was not performed, go to BCM DIAGNOSTIC SYSTEM CHECK under SYSTEM TESTS.
- Turn ignition off. Disconnect scan tool. Disconnect negative battery cable. Disconnect splice pack SP205. See COMPONENT LOCATIONS . Using DVOM, individually check resistance between SP205 terminal "A" and each terminal "B", "E", "G", "L", and "M". See WIRING DIAGRAMS . See Fig 1 . If resistance is less than 2 ohms at all terminals, go to next step. If resistance is greater than 2 ohms at all terminals, go to step 7 .
- Disconnect PCM Blue 80-pin connector C1. Using DVOM, check resistance between SP205 harness connector terminal "B" (Dark Green wire) and ground. If resistance is infinite, go to next step. If resistance is not infinite, go to step 8 .
- Turn ignition on. Using DVOM, check voltage between SP205 harness connector terminal "B" (Dark Green wire) and ground. If reading is less than 2 volts, go to next step. If reading is greater than 2 volts, go to step 9 .
- Using DVOM, check resistance between SP205 harness connector terminal "B" (Dark Green wire) and PCM harness connector C1 terminal No. 59 (Dark Green wire). If resistance is less than 2 ohms, go to next step. If resistance is greater than 2 ohms, go to step 10 .
- Turn ignition off. Reconnect PCM connector C1. Connect scan tool. Turn ignition on. Using scan tool, attempt to establish communication with PCM. If scan tool communicates with PCM, go to step 12 . If scan tool does not communicate with PCM, go to step 11 .
- Replace splice pack SP205. Go to step 13 .
- Repair short to ground in Dark Green wire between PCM connector C1 and splice pack SP205. Go to step 13 .
- Repair short to battery in Dark Green wire between PCM connector C1 and splice pack SP205. Go to step 13 .
- Repair poor connection or open in Dark Green wire between PCM connector C1 and splice pack SP205. Go to next step.
- Class 2 serial data line is okay, but PCM is not communicating class 2 data because of internal malfunction. Go to appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE to diagnose and repair problem.
- System is operating properly at this time. See DIAGNOSTIC AIDS . After any repairs are made, go to next step.
- Turn ignition off. Reinstall all components and connectors. Turn ignition on. Using scan tool, clear DTCs. Check for DTCs. If any DTCs are current, perform BCM DIAGNOSTIC SYSTEM CHECK under SYSTEM TESTS. If no DTCs are current, system is operating properly.