Test Description

The numbers below refer to the step numbers on the diagnostic table.

2: This step tests the PCM TRC - high and TRC - low circuits to the EBCM for an open, high resistance, or short.
3: This step tests the PCM ENG - high and ENG - low circuits to the EBCM for an open, high resistance, or short.
4: Test the PCM ground circuits for an open or high resistance.

DTC C1203

Step	Action	Yes	No
Schematic Reference: Antilock Brake System Schematics Connector End View Reference: Antilock Brake System Connector End Views
1	Did you perform the Diagnostic System Check - Vehicle?	Go to Step 2	Go to Diagnostic System Check - Vehicle
2	Test the powertrain control module (PCM) TRC - high and TRC - low circuits to the electronic brake control module (EBCM) for an open, high resistance, or short. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?	Go to Step 6	Go to Step 3
3	Test the PCM ENG - high and ENG - low circuits to the EBCM for the following: An open High resistance Short to ground Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?	Go to Step 6	Go to Step 4
4	Test the PCM ground circuits for an open or high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?	Go to Step 6	Go to Step 5
5	Replace the brake pressure modulator valve (BPMV). Refer to Brake Modulator Assembly Replacement (With VSC) or Brake Modulator Assembly Replacement (Without VSC) . Did you complete the replacement?	Go to Step 6	-
6	Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC, as specified in the supporting text. Does the DTC reset?	Go to Step 2	System OK