Antilock Braking System (ABS)

DTC 14 ABS Relay Contacts Circuit Open:

Circuit Description:
Ignition voltage is supplied to terminal "86" of the ABS relay. The EBCM/EBTCM is then able to energize the pull-in coil by completing the ground circuit at EBCM/EBTCM terminal "2." The magnetic field created closes the ABS relay contacts and allows battery voltage and current to be supplied to the EBCM/EBTCM, which supplies power to the motors and solenoids.

DTC Will Set When:
DTC 14 can be set anytime after the EBCM/EBTCM commands the ABS 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 and solenoids. This malfunction indicates voltage is not available and would therefore not allow ABS operation if required.

Action Taken:
A malfunction DTC is stored, ABS is disabled and the ABS indicator 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/EBTCM is sensing battery voltage at terminal "C".
2. Checks for proper operation of the ABS relay and related circuitry.
3. Checks for excessive resistance in the switched battery input circuitry.
4. Checks for excessive resistance in the battery feed circuit.
5. Checks for excessive resistance in the ABS relay contacts.
6. Determines if the malfunction is due to poor terminal contact.
7. Determines if the malfunction is due to the EBCM/EBTCM
8. Checks for excessive resistance in the ABS relay control circuitry.
9. Checks for proper battery voltage.
10. Checks for an open in the BATTERY feed circuit.
11. Checks for an open in the switched battery input circuit.
12. Checks for proper operation of the ABS relay.
13. Checks for excessive resistance in the ABS relay coil.
14. Checks for excessive resistance in the ABS relay control circuit between the relay and the EBCM/EBTCM.
15. Checks for excessive resistance in the battery feed circuit to the ABS relay.

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 DTC 14 only sets when the vehicle is initially started in cold ambient conditions, temperature less than 32°F (0°C), replace the ABS relay.