TX Failure

TX FAILURE

WHEN MONITORED
With the ignition on.

SET CONDITION
If the A/C Heater Control is unable to broadcast a PCI Bus message.

POSSIBLE CAUSES
- PCI Bus circuit faults
- A/C Heater control

Diagnostic Test

1. VERIFY THAT THE A/C HEATER CONTROL IS ACTIVE ON THE BUS
Turn the ignition on.
With the DRBIII(R), attempt to communicate with the HVAC Module.

Q: Was the DRBIII(R) able to I/D or communicate with the HVAC Module?

YES: Go To 2
NO: For No Response diagnostic procedures. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

2. CHECK FOR ADDITIONAL DTCS IN THE A/C HEATER CONTROL
With the DRBIII(R), read active HVAC DTCs.

Q: Does the DRBIII(R) display any additional DTCs?

YES: Diagnose and repair the DTC(s). Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 3

3. VERIFY THAT THE PCM OR ECM & CLUSTER ARE ACTIVE ON THE BUS
With the DRBIII(R), attempt to communicate with the PCM (for gasoline engines) or the ECM (for diesel engines) and the Cluster.

Q: Was the DRBIII(R) able to I/D or communicate with these modules?
YES: Go To 4
NO: For No Response diagnostic procedures. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

4. VERIFY THE TX FAILURE DTC IS ACTIVE
With the DRBIII(R), erase HVAC DTCs.
Cycle the ignition switch and wait approximately one minute.
With the DRBIII(R), read active HVAC DTCs.

Q: Does the DRBIII(R) display: TX Failure?

YES: Replace the A/C Heater Control. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: A technician may not have erased this DTC following a module or PCI Bus repair. If possible, verify if the vehicle was recently in for this type of service. Otherwise, visually inspect the related wiring harness for chafed, pierced, pinched, and partially broken wires and the wiring harness connectors for broken, bent, pushed out, and corroded terminals. Repair as necessary. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test