Buick Regal: DTC C025E
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.
- Refer to Diagnostic Procedure Instructions for an overview of each
diagnostic category.
DTC Descriptor
DTC C025E
Brake Booster Vacuum Sensor Circuit
For symptom byte information refer to Symptom Byte List.
Diagnostic Fault Information
Circuit/System Description
The brake booster vacuum sensor monitors the pressure in the brake booster.
The electronic brake control
module supplies a 5 V reference and a low reference circuit to the brake booster
vacuum sensor. The
vacuum sensor supplies a voltage signal in relation to the pressure in the brake
booster to the electronic
brake control module.
Conditions for Running the DTC
C025E 00, C025E 01, C025E 06, C025E 1F
Ignition ON
C025E 5A
- Ignition ON.
- Brakes are not applied.
Conditions for Setting the DTC
C025E 00
- A short to ground is detected on the 5V reference circuit.
- A short to voltage is detected on the 5V reference circuit.
C025E 01
- A short to voltage is detected on the signal circuit.
- An open/high resistance is detected on the low reference circuit.
C025E 06
- An open/high is detected on the signal circuit.
- A short to ground is detected on the signal circuit.
- An open/high is detected on the 5V reference circuit.
C025E 1F
The vacuum sensor signal is erratic.
C025E 5A
The vacuum sensor signal is not plausible.
Action Taken When the DTC Sets
Service Brake Assist message is displayed on the driver information center
Conditions for Clearing the DTC
The DTC clears when the diagnostic runs and passes
Reference Information
Schematic Reference
Hydraulic Brake Wiring Schematics
Connector End View Reference
Component Connector End View Index
Description and Operation
Brake Assist System Description and Operation
Electrical Information Reference
- Circuit Testing
- Connector Repairs
- Testing for Intermittent Conditions and Poor Connections
- Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Refer to Control Module References for scan tool information
Circuit/System Verification
1. Verify that the brake booster vacuum system has no damage, leakage or
incorrect installation.
- If damage, leakage or incorrect installation is found
Refer to Brake Assist System Diagnosis
- Go to next step: If no damage, leakage or incorrect installation is
found
2. Refer to Circuit/System Testing.
Circuit/System Testing
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector
at the B19B Brake
Booster Vacuum Sensor. It may take up to 2 min for all vehicle systems to power
down.
2. Test for less than 10 Ω between the low reference circuit terminal 2 and
ground.
- Disconnect the harness connector at the K17 Electronic Brake Control
Module.
- Test for less than 2 Ω in the low reference circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K17 Electronic Brake Control Module.
- Go to next step: If less than 10 Ω
3. Ignition ON.
4. Test for 4.8 - 5.2 V between the 5 V reference circuit terminal 3 and
ground.
- Ignition OFF, disconnect the harness connector at the K17 Electronic
Brake Control Module.
- Test for infinite resistance between the 5 V reference circuit and
ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in the 5 V reference circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K17 Electronic Brake Control Module.
If greater than 5.2 V
- Ignition OFF, disconnect the harness connector at the K17 Electronic
Brake Control Module,
ignition ON.
- Test for less than 1 V between the 5 V reference circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K17 Electronic Brake Control Module.
- Go to next step: If between 4.8 - 5.2 V
5. Ignition OFF, disconnect the harness connector at the K17 Electronic Brake
Control Module,
Ignition ON.
6. Test for less than 1 V between the B19B Brake Booster Vacuum Sensor signal
circuit terminal 1 and
ground.
Repair the short to voltage on the circuit.
- Go to next step: If less than 1 V
7. Ignition OFF.
8. Test for infinite resistance between the B19B Brake Booster Vacuum Sensor
signal circuit terminal 1
and ground.
- If less than infinite resistance
Repair the short to ground on the circuit.
- Go to next step: If infinite resistance
9. Test for less than 2 Ω between the B19B Brake Booster Vacuum Sensor signal
circuit terminal 1 and
the K17 Electronic Brake Control Module signal circuit terminal 34.
Repair the open/high resistance in the circuit.
- Go to next step: If less than 2 Ω
10. Test or replace the B19B Brake Booster Vacuum Sensor.
11. Verify the DTC does not set while operating the vehicle under Conditions for
Running the DTC.
Replace the K17 Electronic Brake Control Module.
- Go to next step: If the DTC does not set
12. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
- Refer to Power Brake Booster Vacuum Sensor Replacement (2.0L LTG) or
Power Brake
Booster Vacuum Sensor Replacement (3.6L LGX)
- Refer to Control Module References for electronic brake control module
replacement,
programming and setup
READ NEXT:
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.
Refe
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.
Refe
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.
Refe
SEE MORE:
Special Tools
J-42572 Drive Shaft Seal Clamp Pliers
Disassembly Procedure
1. Rear Wheel Drive Shaft - Remove
Rear Wheel Drive Shaft Replacement - Left Side
Rear Wheel Drive Shaft Replacement - Right Side
2. Place the wheel drive shaft horizontally in a bench vise.
3.
Using a side cutter or oth
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
D