Diagnostic Instructions
DTC Descriptor
DTC C0870: Voltage Reference Output 1 Circuit
Circuit/System Description
The steering wheel speed position sensor and the yaw rate and lateral acceleration sensor reference voltages are monitored for an over or under voltage condition.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
When the electronic brake control module (EBCM) detects the supply voltage is above 5.6 volts or below 4.4 volts for more than 60 milliseconds for the steering wheel speed position sensor or the yaw rate and lateral acceleration sensor.
Action Taken When the DTC Sets
If equipped, the following actions will occur:
| • | The EBCM disables the vehicle stability enhancement system (VSES) for the duration of the ignition cycle. |
| • | The driver information center (DIC) displays the Service Stability System message. |
| • | The EBCM disables the traction control system (TCS) for the duration of the ignition cycle. |
| • | The DIC displays the Service Traction Control System message. |
Conditions for Clearing the DTC
| • | The DTC will be current for as long as the fault is present. |
| • | When the fault is no longer present, the DTC will be a history DTC. |
| • | A history DTC will clear after 100 ignition cycles. |
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
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the appropriate sensor.
- Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal and ground for the sensor listed below:
| • | Steering wheel speed position sensor 5-volt reference circuit terminal 1. |
| • | Yaw rate and lateral acceleration sensor 5-volt reference circuit B. |
| ⇒ | If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the EBCM. |
| ⇒ | If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the EBCM. |
- If all circuits test normal, replace the appropriate sensor.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
