Chart A, Scan Tool Will Not Communicate: Testing

1. Enter on-board diagnostics. If on-board diagnostics can be entered, go to next step. If on-board diagnostics cannot be entered, go to step 3).
2. Turn ignition switch to OFF position. Disconnect PZM connector. Using DVOM, check resistance between Data Link Connector (DLC) terminal No. 2 (Purple wire) and PZM 24-pin connector C1 terminal B9 (Purple wire). If resistance is 5 ohms or less, scan tool may be malfunctioning. See scan tool manufacturer's instructions. If resistance is greater than 5 ohms, repair open in Purple wire.
3. Turn ignition switch to OFF position. Disconnect all modules connected to Class 2 serial data line. Using DVOM, check resistance between DLC terminal No. 2 (Purple wire) and ground. If resistance is infinite, go to next step. If resistance is not infinite, repair short to ground in Purple wire.
4. Turn ignition switch to ON position. Using DVOM, check voltage between DLC terminal No. 2 (Purple wire) and ground. If no voltage exists, go to next step. If any voltage exists, repair short to voltage in Purple wire.
5. Turn ignition switch to OFF position. Ensure Instrument Panel Cluster (IPC) is connected. Using scan tool, attempt to establish communications with IPC. If communication can be established, go to next step. If communication cannot be established, replace IPC. See appropriate INSTRUMENT PANEL article.
6. Ensure ignition switch is in OFF position. In the following order, individually reconnect each module (if equipped):
   • Body Control Module (PZM)
   • Remote Function Actuator (RFA)
   • Instrument Panel Cluster (IPC)
   • Sensing & Diagnostic Module (SDM)
   • Electronic Brake Traction Control Module (EBTCM)
   • Powertrain Control Module (PCM)
   • Heater & A/C Programmer (ACM)
   • Amplifier
   • Electronic Suspension Module
   • Radio (IRC)
   • Memory Seat Module (MSM)
   • Cellular Phone Module (PHN)
   • Memory Mirror Module (MMM)
   • Climate Control Panel (CCP)

Using scan tool, attempt to establish communication with reconnected module. When communication cannot be established, replace most recently connected module.