2007 Cadillac Escalade EXT
Mileage
135,010
Service Date
11/26/2024
Services Performed
- FOUND: after the vehicle ran for a period of time it was determined that communication was being lost on the high-speed controller area Network (CAN) data bus. Both the transmission control module and the engine control module stopped communicating with the scan tool. The vehicle at this time would not start. There were codes in multiple control modules for communication data loss. Scope tested the can data bus at the diagnostic connector and found an abnormal voltage waveform indicating a possible open circuit in the wiring harness or in a module. The body control module under the driver side of the dash was accessed to allow the circuit to be tested to determine if one of the termination resistors was not present on the data bus. The ohm meter showed that at the time of the fault the 120 ohm termination resistor in the engine control module was not present on the network. The engine control module was accessed and the termination resistor was checked and found to be good. This pointed to a possible problem with the wiring at the transmission control module, wiring from transmission control module to body control module, or the engine control module. Further diagnosis time needed to confirm failure.
- FOUND: please see the first repair line item for an explanation of the can data bus communication fault.
- FOUND: Trace/diagnose possible problem with the wiring at the transmission control module, the transmission control module itself, or a problem with the wiring between the transmission control module and the engine control module. The transmission control module connector was accessed and one of the pins that carries the data for the can data bus was found to be receded into the connector and not making good contact with the in the transmission. The terminal pin connection was repaired and the vehicle was allowed to run for an extended period of time. The communication Network remained active and no trouble codes were set in the engine control module or transmission control module. The instrument cluster operation also remained normal.
ARTHUR S. gave our service a 5 star review on 11/30/2024
