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Home >> Cadillac >> 2006 >> XLR Base >> Repair and Diagnosis >> Brakes >> Antilock Brake System With Traction Control System & Stability Control System >> Diagnostic Information and Procedures >> DTC C0870 >> Test Description

Test Description

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

  1. 5:  Tests for a short at the brake pressure sensor.
  2. 6:  Tests for a short at the steering wheel position sensor.
  3. 7:  Tests for a short at the yaw rate/lateral accelerometer sensor.
DTC C0870

Step Action Values Yes No
Schematic Reference: Anti-Lock Brake System Schematics 
Connector End View Reference: Anti-Lock Brake System 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 Test the 5-volt reference circuit from the electronic brake control module (EBCM) for the following conditions:
  • An open
  • A short to ground
  • A high resistance

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 16  Go to Step 3 
3 Test the 5-volt reference circuit from the EBCM for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 16  Go to Step 4 
4
  1. Turn OFF the ignition.
  2. Disconnect the EBCM.
  3. Install the J 39700  Universal Pinout Box with the J 39700-530  Cable Adapter between the EBCM and the EBCM harness connector. See Special Tools .
  4. Turn ON the ignition, with the engine OFF.
  5. Using the DMM, measure the voltage between the 5 volt reference circuit and ground.
Is the voltage within the specified value?		 4.8-5.2 V Go to Diagnostic Aids Go to Step 5 
5 
  1. Turn OFF the ignition.
  2. Disconnect the brake pressure sensor.
  3. Turn ON the ignition, with the engine OFF.
  4. Using the DMM, measure the voltage between the 5-volt reference circuit and ground.
Is the voltage within the specified value?		 4.8-5.2 V Go to Step 8  Go to Step 6 
6 
  1. Turn OFF the ignition.
  2. Disconnect the steering wheel position sensor connector
  3. Turn the ignition ON, with the engine OFF.
  4. Using the DMM, measure the voltage between the 5-volt reference circuit and ground.
Is the voltage within the specified value?		 4.8-5.2 V Go to Step 9  Go to Step 7 
7 
  1. Turn OFF the ignition.
  2. Disconnect the yaw rate/lateral accelerometer sensor connector
  3. Turn the ignition ON, with the engine OFF.
  4. Using the DMM, measure the voltage between the 5-volt reference circuit and ground.
Is the voltage within the specified value?		 4.8-5.2 V Go to Step 10  Go to Step 11 
8 Inspect for poor connections at the harness connector of the brake pressure sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 16  Go to Step 12 
9 Inspect for poor connections at the harness connector of the steering wheel position sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 16  Go to Step 13 
10 Inspect for poor connections at the harness connector of the yaw rate/lateral accelerometer sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 16  Go to Step 14 
11 Inspect for poor connections at the harness connector of the EBCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 16  Go to Step 15 
12 Replace the brake pressure sensor. Refer to Brake Fluid Pressure Sensor Replacement .
Did you complete the replacement?		 - Go to Step 16  -
13 Replace the steering wheel position sensor. Refer to Steering Wheel Position Sensor Replacement in Steering Wheel and Column.
Did you complete the replacement?		 - Go to Step 16  -
14 Replace the yaw rate/lateral accelerometer sensor. Refer to Vehicle Yaw Sensor with Vehicle Lateral Accelerometer Replacement .
Did you complete the replacement?		 - Go to Step 16  -
15 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 16  -
16
  1. Clear the DTCs using the scan tool.
  2. 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
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