Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC C1101: Base Brake System Pressure Sensor Circuit PerformanceDTC C1102: Base Brake System Pressure Sensor Circuit Low Voltage
DTC C1103: Base Brake System Pressure Sensor Circuit High Voltage
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
5-Volt Reference | C1102 | C1102 | C1103 | C1101 |
Brake Fluid Pressure Sensor Signal | C1102 | C1102 | C1103 | C1101 |
Low Reference | -- | C1102 | -- | -- |
Circuit/System Description
The brake pressure sensor monitors the line pressure down stream from the master cylinder. The ECM receives inputs from the brake pressure sensor and communicates via serial data with the SGCM for the hill hold functions.
Conditions for Running the DTC
C1101
| • | Engine is running and vehicle speed is above 40 km/h (25 mph), or engine is running and vehicle is stopped after reaching a speed equal to or greater than 40 km/h (25 mph). |
| • | DTCs C1102, C1103 or vehicle speed DTCs have not set. |
| • | The transmission is in drive. |
C1102 or C1103
Ignition ON.
Conditions for Setting the DTC
C1101
The EBCM detects that the brake pressure sensor indicates the brake is on
C1102
The ECM detects a short to ground or open with the sensor signal circuit or the brake pressure sensor.
C1103
The ECM detects an open with the sensor ground or a short to voltage in either the signal circuit or the brake pressure sensor.
Action Taken When the DTC Sets
DTCs C1101, C1102 or C1103 are Type B DTCs.
Conditions for Clearing the DTC
DTCs C1101, C1102 or C1103 are Type B DTCs.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Hill Hold Control Description and Operation
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the brake fluid pressure sensor.
- Ignition OFF, test for less than 5 ohms between the low reference circuit terminal A and ground.
- Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal B and ground.
- Verify the scan tool ECM Brake Fluid Pressure Sensor parameter is less than 0.15 volt.
- Install a 3A fused jumper wire between the signal circuit terminal C and the 5-volt reference circuit terminal B. Verify the scan tool ECM Brake Fluid Pressure Sensor parameter is greater than 4.75 volts.
- If all circuits test normal, test or replace the brake master cylinder pressure sensor.
| ⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
| ⇒ | 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 ECM. |
| ⇒ | If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
| ⇒ | If greater than the specified range, test the signal circuit terminal for a short to voltage. If the circuit tests normal, replace the ECM. |
| ⇒ | If less than the specified range, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for ECM replacement, setup, and programming |
