C1101
DTC C1101-C1103
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
DTC Descriptors
DTC C1101
- Base Brake System Pressure Sensor Circuit Performance
DTC C1102
- Base Brake System Pressure Sensor Circuit Low Voltage
DTC C1103
- Base Brake System Pressure Sensor Circuit High Voltage
Diagnostic Fault Information
Circuit/System Description
The brake pressure sensor measures the line pressure down stream from the master cylinder. The ECM monitors the brake pressure to determine when to command the EBCM to apply and release the front brakes for the hill hold function.
Conditions for Running the DTC
C1101
After the vehicle speed is above 40 km/h (25 mph) and stopped 6 times.
C1102 or C1103
Ignition ON.
Conditions for Setting the DTC
C1101
The EBCM detects the brake pressure sensor reading is stuck indicating the brakes are applied.
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
DTC C1101-C1103 are Type B DTCs.
Conditions for Clearing the DTC
DTC C1101-C1103 are Type B DTCs.
Reference Information
Schematic Reference
Antilock Brake System Schematics (without HP7) ([1][2]Antilock Brakes / Traction Control Systems)Antilock Brake System Schematics (HP7) ([1][2]Antilock Brakes / Traction Control Systems)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Hill Hold Control Description and Operation (Hill Hold Control Description and Operation)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the brake master cylinder pressure sensor.
2. Ignition OFF, test for less than 5 ohms between the low reference circuit terminal 1 and ground.
• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 2 and ground.
• 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.
4. Verify the scan tool ECM Brake Fluid Pressure Sensor 2 parameter is less than 0.15 volt.
• If greater than the specified range, test the signal circuit terminal 3 for a short to voltage. If the circuit tests normal, replace the ECM.
5. Install a 3A fused jumper wire between the signal circuit terminal 3 and the 5-volt reference circuit terminal 2. Verify the scan tool ECM Brake Fluid Pressure Sensor 2 parameter is greater than 4.75 volts.
• 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.
6. If all circuits test normal, test or replace the brake master cylinder pressure sensor.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Brake Master Cylinder Pressure Sensor Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for ECM replacement, setup, and programming