Self-Check Diagnostics

The CMTC is capable of performing a diagnostic self check on its internal functions. CMTC diagnostics may be performed using a DRBIII® or by using the following procedure:

1. With the ignition switch in the OFF position, depress and hold the STEP and the US/M buttons.
2. Turn the ignition switch to the On position and release the buttons.
3. All of the VFD segments will illuminate for 2-4 seconds. Check for segments that do not illuminate or illuminate all the time.
4. When the self-check is complete the CMTC will display one of the following five messages:
   • F (FAIL)
   • P (PASS)
   • Bus (No PCI bus communication)
   • Bus 1 (No PCM bus messages received)
   • Bus 2 (No BCM bus messages received)
5. To exit the self-check mode, depress the STEP button or cycle the ignition switch and the CTM will return to normal operation.

If a Bus fault is displayed, refer to the symptom list. If an F is displayed, the CMTC must be replaced. The CMTC will not display an F for a VF segment that does not illuminate.