DTC C123C, C1255, or C1256
| DTC C123C, C1255, or C1256 | 
| Diagnostic Instructions | 
| • | Perform the
        
         Diagnostic System Check - Vehicle
        
        prior to using this diagnostic procedure. | |
| • | Review
        
         Strategy Based Diagnosis
        
        for an overview of the diagnostic approach. | |
| • | Diagnostic Procedure Instructions
        
        provides an overview of each diagnostic category. | |
| DTC Descriptors | 
DTC C123C 00
Electronic Brake Control Module RAM Malfunction
DTC C1255 00
Electronic Control Unit Performance Malfunction
DTC C1256 00
Control Module Programming Checksum Error Malfunction
| Circuit/System Description | 
When the ignition is turned ON, the microprocessor runs a diagnostic program to detect an internal fault when power up is commanded. If an internal malfunction is detected, the control module will set a DTC.
| Conditions for Running the DTC | 
Ignition ON
| Conditions for Setting the DTC | 
The control module detects an internal malfunction.
| Action Taken When the DTC Sets | 
Specific subsystems will not function or operate in degraded mode.
| Conditions for Clearing the DTC | 
A current DTC clears when the diagnostic runs and passes.
| Reference Information | 
Schematic Reference
Antilock Brake System Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
ABS Description and Operation
Electrical Information Reference
| • | Circuit Testing | |
| • | Connector Repairs | |
| • | Testing for Intermittent Conditions and Poor Connections | |
| • | Wiring Repairs | |
Scan Tool Reference
Control Module References for scan tool information
| Circuit/System Testing | 
| 1. | Ignition ON, verify that DTC C0569, C056D, or C056E is not present in the electronic brake control module (EBCM). | |
| 2. | If any listed DTC is present, refer to
        
         Diagnostic Trouble Code (DTC) List - Vehicle
        
        to diagnose that DTC prior to this diagnostic. | |
| 3. | Replace the K17 Electronic Brake Control Module and verify the DTC does not reset. | |
| 4. | If the DTC resets, replace the module that set the DTC. | |
| Repair Instructions | 
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for module replacement, setup and programming

 
		