The electronic brake control module (EBCM) supplies voltage to the brake pressure sensor, steering angle sensor, and yaw rate/lateral accelerometer sensor. This voltage is monitored by the EBCM for an over or under voltage condition.
This diagnostic procedure supports the following DTC:
DTC C0870 Device Voltage Reference Output Circuit
• | The ignition is ON. |
• | Ignition voltage is greater than 8 volts. |
One of the follow conditions exists for 0.1 seconds:
• | The sensor supply voltage is greater than 5.2 volts. |
• | The sensor supply voltage is less than 4.8 volts. |
• | The EBCM disables the VSES for the duration of the ignition cycle. |
• | ACC braking function disabled. |
• | TCS is degraded. |
• | The Traction Control and Active Handling indicator turns ON. |
• | The DIC displays the Service Active Handling message. |
• | The condition for the DTC is no longer present and the DTC is cleared with a scan tool. |
• | The electronic brake control module (EBCM) automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles. |
The following conditions can cause this concern:
• | The sensor supply circuit is open, shorted to ground, or shorted to battery. |
• | Internal sensor malfunction. |
• | Internal EBCM malfunction. |
The numbers below refer to the step numbers on the diagnostic table.
Tests for a short at the brake pressure sensor.
Tests for a short at the steering wheel position sensor.
Tests for a short at the yaw rate/lateral accelerometer sensor.
Step | Action | Values | 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 | |||||||
2 | Test the 5-volt reference circuit from the electronic brake control module (EBCM) for the following conditions:
Refer to Circuit Testing and Wiring Repairs . 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 . Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 4 | ||||||
4 |
Is the voltage within the specified value? | 4.8-5.2V | Go to Diagnostic Aids | Go to Step 5 | ||||||
Is the voltage within the specified value? | 4.8-5.2V | Go to Step 8 | Go to Step 6 | |||||||
Is the voltage within the specified value? | 4.8-5.2V | Go to Step 9 | Go to Step 7 | |||||||
Is the voltage within the specified value? | 4.8-5.2V | 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 . 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 . 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 . 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 . Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 15 | ||||||
12 | Replace the brake pressure sensor. Refer to Brake Pressure Modulator Valve Pressure Sensor Replacement . Did you complete the repair? | -- | Go to Step 16 | -- | ||||||
13 | Replace the steering wheel position sensor. Refer to Steering Wheel Position Sensor or Steering Shaft Lower Bearing Replacement . Did you complete the repair? | -- | 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 repair? | -- | Go to Step 16 | -- | ||||||
15 | Replace the EBCM. Refer to Control Module References for replacement, setup and programming. Did you complete the replacement? | -- | Go to Step 16 | -- | ||||||
16 |
Does the DTC reset? | -- | Go to Step 2 | System OK |