Test Description

WARNING: This page is about a different car, the 2005 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.

The number below refers to the step number on the diagnostic table.

2: Determines whether the DTC is current.

DTC C0121

Step	Action	Values	Yes	No
Schematic Reference: ABS Schematics Connector End View Reference: ABS Connector End Views
1	Did you perform the Diagnostic System Check - Vehicle?	-	Go to Step 2	Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2	Install a scan tool. Turn ON the ignition, with the engine OFF. Use the scan tool in order to clear the DTCs. With the scan tool, perform the Automated Test. Does the DTC reset as a current DTC?	-	Go to Step 3	Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems
3	Disconnect the pump motor harness pigtail connector of the brake pedal modulator valve (BPMV). Measure the resistance between each pump motor control circuit and the housing of the BPMV at the pump motor harness pigtail connector of the BPMV. Does the DMM display the specified value?	OL	Go to Step 5	Go to Step 4
4	Replace the electronic brake control module (EBCM) and the BPMV. Refer to Control Module References in Computer/Integrating Systems for replacement, setup and programming and Brake Pressure Modulator Valve (BPMV) Replacement (CTS) or Brake Pressure Modulator Valve (BPMV) Replacement (CTS-V) . Did you complete the replacement?	-	Go to Step 6	-
5	Replace the EBCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup and programming. Did you complete the replacement?	-	Go to Step 6	-
6	Use the scan tool in order to clear the DTCs. With the scan tool, perform the Automated Test. Does the DTC reset?	-	Go to Step 2	System OK