Antilock Braking System (ABS)

DTC 14 ABS Enable Relay Contact Circuit Open (Part 1 Of 3):

DTC 14 ABS Enable Relay Contact Circuit Open (Part 2 Of 3):

DTC 14 ABS Enable Relay Contact Circuit Open (Part 3 Of 3):

DTC 14 ABS Enable Relay Contact Circuit Open:

Circuit Description:
Ignition voltage is supplied through terminal "86" of the ABS enable relay. The EBCM is then able to energize the pull-in coil by completing the ground circuit at EBCM terminal "22" (ABS w/o VES) or "20" (ABS w/VES). The magnetic field created closes the enable relay contacts and allows battery voltage and current to be supplied to the EMB's, EVO actuator (ABS w/VES), and EBCM, which supplies power to the motors and solenoids.

DTC Will Set When:
DTC 14 can be set anytime after the EBCM commands the enable relay "ON" (the relay is first commanded "ON" during the three second bulb check). This test monitors the availability of current/voltage to the motors, solenoids, and EMB's and EVO actuator. This malfunction indicates voltage is not available and would therefore not allow ABS operation if required.

Action Taken:
A malfunction DTC is stored, ABS/VES is disabled and the ABS warning lamp is turned "ON."

DTC Chart Test Description:
Number(s) below refer to circled number(s) on the diagnostic chart.
1. Checks to see if the EBCM is sensing battery voltage at terminal "A".
2. Checks for proper operation of the enable relay and related circuitry.
3. Checks for excessive resistance in the switched battery input circuitry.
4. Checks for excessive resistance in the B+ feed circuit.
5. Checks for excessive resistance in the enable relay contacts.
6. Determines if the malfunction is due to poor terminal contact.
7. Determines if the malfunction is due to the EBCM.
8. Checks for excessive resistance in the enable relay control circuitry.
9. Checks for proper battery voltage.
10. Checks for an open in the B+ feed circuit.
11. Checks for an open in the switched battery input circuit.
12. Checks for proper operation of the enable relay.
13. Checks for excessive resistance in the enable relay coil.
14. Checks for excessive resistance in the enable relay control circuit between the relay and the EBCM.
15. Checks for excessive resistance in the ignition switch "run" fuse feed circuit.

Diagnostic Aids:
An "Intermittent" malfunction is most likely caused by a poor connection, rubbed through wire insulation, or a wire that is broken inside the insulation.

The frequency of the malfunction is most likely checked by using the enhanced diagnostic function of the Tech 1.

Any circuitry that is suspected as 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:

Check for vibration effects by performing the relay test function of the Tech 1. With the relay commanded "ON," lightly tap the top and sides of the relay while monitoring battery voltage. If the battery voltage changes significantly, replace the relay.

If test 14 only fails when the vehicle is initially started in cold ambient conditions (temperature less than 32°F - 0°C),replace the relay.