C12E8
DTC C0110, C12E0, C12E8, or C12E9
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle
* Review Strategy Based Diagnosis Strategy Based Diagnosis
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions
DTC Descriptors
DTC C0110 00
- Pump Motor Circuit
DTC C0110 61
- Pump Motor Circuit Actuator Stuck
DTC C12E0 00
- ABS Pump Motor Performance
DTC C12E8 00
- ABS Pump Motor Stuck
DTC C12E9 00
- ABS Pump Motor Stuck On
Diagnostic Fault Information
Circuit/System Description
The pump motor is a bi-directional motor and is an internal part of the brake pressure modulator valve assembly. There are three solid state relays in the electronic brake control module (EBCM) that operate the pump. The pump motor runs every few brake stops in order to fill the high pressure accumulator with brake fluid.
Conditions for Running the DTC
* Ignition ON.
* Ignition voltage is greater than 10 V.
* The system enable relay is ON.
* The pump motor has been commanded ON, OFF and ON again.
Conditions for Setting the DTC
* The EBCM detects a short to ground or an open/high resistance on the B+ circuit.
* The EBCM detects an open/high resistance on the ground circuit.
* The EBCM detects the pump motor runs continuously.
* The EBCM detects the pump motor is binding or stalled.
* The brake pressure accumulator is not charging.
Action Taken When the DTC Sets
* The EBCM disables the antilock brake system (ABS), traction control and the vehicle stability enhancement system for the duration of the ignition cycle.
* The ABS indicator illuminates.
* The red Brake indicator illuminates.
* The Stability Control indicator illuminates.
* A driver information center message and/or a warning indicator may be displayed.
Conditions for Clearing the DTC
* The condition for the DTC is no longer present and the vehicle speeds are greater than 15 km/h (10 mph) to complete the EBCM self test, then the ABS indicator will turn off.
* The EBCM clears the history DTC when a current DTC is not detected in 40 consecutive drive cycles.
Diagnostic Aids
* Find out from the customer the conditions under which the DTC was set. This information may help duplicate the concern like the specific number of brake pedal applies in a row prior to the fault set.
* Check for hydraulic leaks, air in the brake system or incorrect brake bleed.
Reference Information
Schematic Reference
Antilock Brake System Schematics [1][2]Antilock Brakes / Traction Control Systems
Connector End View Reference
Component Connector End Views Hybrid/EV Battery Pack X1 A4
Description and Operation
ABS Description and Operation Description and Operation
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON, perform the ABS Motor test with a scan tool. You should hear or feel the ABS pump motor turn ON and OFF.
• If the pump motor does not turn ON and OFF, refer to Circuit/System Testing.
Note: To ensure the complete brake modulator and high pressure accumulator (HPA) pressure relief procedure is allowed to occur; the brake controller must see 1 pedal apply with the propulsion system enabled, followed by a proper shutdown without applying the brake pedal.
2. Enable the propulsion system, place the transmission in PARK, apply and release the brake pedal.
Note: The power button must be in the OFF position, and without applying the brake pedal to ensure the brake modulator and high pressure accumulator (HPA) pressure relief occurs. This process will take approximately 1-3 minutes.
3. Place the power button in the OFF position, without applying the brake pedal.
4. Remove the remote keyless entry (RKE) transmitter and close all of the vehicle doors.
5. Wait approximately 1-3 minutes until the brake modulator and the high pressure accumulator (HPA) pressure relief is complete.
6. Place the power button in the ON position, engine OFF, and do not apply the brake pedal.
7. Using the scan tool data display, scroll through the Data List, select and accept Accumulator Pressure Sensor.
8. While observing the Accumulator Pressure Sensor data, activate the propulsion system to pressurize the brake system. The Accumulator Pressure Sensor data should rise from 0 kPa (0 psi) to 17,000 kPa (2466 psi) within 40 seconds.
• If less than 17,000 kPa (2,466 psi) or it takes longer than 40 seconds to build pressure, refer to Brake Hydraulic and Assist System Diagnosis Brake Hydraulic and Assist System Diagnosis.
Circuit/System Testing
1. Ignition OFF all vehicle systems OFF, disconnect the harness connector at the K17 EBCM. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 ohm between the ground circuit terminals listed below and ground:
* Terminal 13
* Terminal 38
• If 10 ohm or greater
1. Ignition OFF
2. Test for less than 2 ohm in the ground circuit end to end.
• If 2 ohm or greater, repair the open/high resistance in the circuit.
• If less than 2 ohm, repair the open/high resistance in the ground connection.
• If less than 10 ohm
3. Ignition ON.
4. Verify that a test lamp illuminates between B+ circuit terminals listed below and ground:
* Terminal 1
* Terminal 25
• If the test lamp does not illuminate and the circuit fuse is good
1. Ignition OFF
2. Test for less than 2 ohm in the B+ circuit end to end.
• If 2 ohm or greater, repair the open/high resistance in the circuit.
• If less than 2 ohm, verify the fuse is not open and there is voltage at the fuse.
• If the test lamp does not illuminate and the circuit fuse is open
1. Ignition OFF
2. Test for infinite resistance between the B+ circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the Q5 brake pressure modulator.
• If the test lamp illuminates
5. Ignition OFF.
6. Remove the K17 EBCM from the Q5 brake pressure modulator.
7. Inspect the K17 EBCM to Q5 brake pressure modulator connector for the conditions listed below:
* Damage
* Corrosion
* Presence of brake fluid
• If connector corrosion or damage is evident, replace Q5 brake pressure modulator and/or K17 EBCM as necessary.
• If brake fluid is present, replace both Q5 brake pressure modulator and K17 EBCM.
• If the K17 EBCM to Q5 brake pressure modulator connector is OK
8. Connect the harness connector at the K17 EBCM with the Q5 brake pressure modulator still separated.
9. Connect a test lamp between the pump motor control and ground circuit terminals, ignition ON.
10. Verify the test lamp turns ON and OFF when commanding the ABS Pump Motor ON and OFF with a scan tool.
• If the test lamp is always OFF or always ON
Replace the K17 EBCM.
• If the test lamp turns ON and OFF
11. Replace the Q5 brake pressure modulator
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Electronic Brake Control Module with Brake Pressure Modulator Valve Replacement Electronic Brake Control Module with Brake Pressure Modulator Valve Replacement
* Control Module References Control Module References for EBCM replacement, programming and setup