Chart C, Loss Of ECCP Communications (Non-CRT Equipped TORONADO & TROFEO)

Fig 1: Chart C - Wiring Schematic (Non-CRT Toronado & Trofeo)

Courtesy of GENERAL MOTORS CORP.

When ECCP communications are lost, service diagnostics usually cannot be entered, but a quick scan of panel will usually help isolate source of fault. ECCP is powered by ignition. If power source is lost, IPC will usually display ELECTRICAL PROBLEM. Loss of serial data will result in 3 dashes being shown on panel VF display. This indicates power and ground are okay. If the panel displays normal outside or interior set temperature, power, ground and serial communications are being received, indicating need to replace panel.

1. This step checks for power and ground to panel. Test light should be on for both power to ground checks.
2. This step checks for serial data voltage. Normal voltage should be above one volt and varying.

Fig 2: Chart C - Troubleshooting Diagram (Non-CRT Toronado & Trofeo)

Courtesy of GENERAL MOTORS CORP.