DTC A014: ABS Enable Relay Contact Circuit Open

ABS ENABLE RELAY CONTACT CIRCUIT OPEN





Circuit Description
Ignition voltage is supplied through terminal 85 of the ABS enable relay. The electronic brake control module (EBCM) then is able to energize the pull-in coil by completing the ground circuit at pin A11 of the EBCM. The magnetic field created closes the ABS enable relay contacts and supplies battery voltage and current to the EBCM, which supplies power to the motors.

Diagnosis
This test checks for continuity in the switched battery circuit to the EBCM. A fault exists if for 0.056 seconds the switched battery voltage falls below 7.5 volts and the ignition voltage is greater than 10.6 volts while the controller output for the relay coil is less than 3.4 volts.

Cause(s)
- There is a blown fuse (from the battery to the relay contacts).
- Relay contacts are malfunctioning.
- There is high resistance in a connector terminal or the wiring.
- There is an open circuit in the switched battery voltage wire.
- The EBCM is faulty.

Fail Action
This is a critical operational fault. The ABS is disabled and the ABS warning lamp is turned on. The brake warning lamp is turned on only if the rear piston is not at the top of the bore. This could cause degradation of the base brakes.

Test Description
The number(s) below refer to step(s) on the diagnostic table.
2. This step checks to see if the EBCM is sensing battery voltage at connector J2, terminal C7.
3. This step checks for improper operation of the ABS enable relay and the related circuitry.
4. This step checks for excessive resistance in the switched battery input circuitry.
5. This step checks for excessive resistance in the 13+ feed circuit.
10. This step determines if the malfunction is due to a poor connection.
12. This step determines if the malfunction is due to the EBCM.
14. This step checks for excessive resistance in the ABS enable relay control circuitry.
15. This step checks for improper battery voltage.
16. This step checks for an open in the B+ feed circuit.
17. This step checks for an open in the switched battery input circuit.
18. This step checks for improper operation of the ABS enable relay.
26. This step checks for excessive resistance in the ignition switch ON feed (Fuse 15) circuit.
27. This step checks for excessive resistance in the ABS enable relay coil.
28. This step checks for excessive resistance in the ABS enable relay control circuit between the relay and the EBCM.
29. This step checks for excessive resistance in the ABS enable relay control circuit between the relay and the I/P harness connector.

Diagnostic Aids
An intermittent malfunction may be caused by a poor connection, wire insulation that has been rubbed through, or a wire that is broken inside the insulation.
The frequency of the malfunction can be checked by using the enhanced diagnostic function of the scan tool as described in "Scan Tool Diagnostics." Scan Tool Diagnostics
Any circuitry that is suspected of causing the intermittent complaint should be thoroughly checked for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wiring connections or physical damage to the wiring harness.

Vibration, Temperature Effects
1. Check for vibration effects by performing the relay test function of the scan tool.
2. Use the scan tool to command the relay ON.
3. Monitor the relay voltage while lightly tapping the top and the sides of the relay.
4. Replace the relay if the voltage changes significantly.
If DTC A014 only occurs when the vehicle is initially started in cold ambient conditions (temperature less than O°C/[32°F]), replace the relay.














DTC A014 - ABS Enable Relay Contact Circuit Open