2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 953

2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 953

Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.

* Control Module References (See: Testing and Inspection/Programming and Relearning) for TCSCM replacement, setup, and programming

* Transfer Case High/Low Clutch Reset (See: Transmission and Drivetrain/Transfer Case/Testing and Inspection/Symptom Related

Diagnostic Procedures/MP 3010-NP0/Transfer Case High/Low Clutch Reset)

MP 3023/3024-NQH - Transfer Case

DTC C0550

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System

Check - Vehicle) prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an

overview of the diagnostic approach.

* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure

Instructions) provides an overview of each diagnostic category.

DTC Descriptors

DTC C0550 37

- Electronic Control Unit (ECU) Performance Watchdog Failure

DTC C0550 39

- Electronic Control Unit (ECU) Internal Electronic Failure

Diagnostic Fault Information

Circuit/System Description

This is an internal fault detection of the transfer case shift control module (TCCM). This fault is handled inside the TCCM. No external circuits are

involved.

At each power-up, the TCCM runs a self-test on the following:

* EEPROM Checksum

* ROM Checksum

* RAM Checksum

* RAM Malfunction

Conditions for Running the DTC

* The TCM runs the program to detect an internal condition at key ON. The only requirements are voltage and ground.

* Ignition ON.

* System voltage 10.5-18.0 V

Conditions for Setting the DTC

* The random access memory (RAM) of the TCCM has failed an operational test indicating that some portions of RAM are not functional.

* The read only memory (ROM) or the masked ROM of the TCCM has failed the Checksum test indicating that the data is not currently valid.

* The critical operational parameters stored in the EEPROM of the TCCM have failed the Checksum test indicating invalid data.

Action Taken When the DTC Sets

* The encoder motor will be deactivated for the remainder of the current ignition cycle.

* The transfer case shift control switch will illuminate the current mode position LED.

* No further mode changes shall be allowed.

* The TCCM will store freeze frame data.

* The SERVICE 4WD indicator remains illuminated for the remainder of the current ignition cycle.

Conditions for Clearing the DTC

* The TCCM will clear the DTC once the conditions for setting the DTC no longer exist.

* A history DTC will clear after 40 consecutive warm up cycles without a fault present.