C1211

(Part 1 Of 4):

(Part 2 Of 4):

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(Part 4 Of 4):

ABTS/TCS Circuit Schematic:

CIRCUIT DESCRIPTION
When the ignition is first turned to RUN, the Electronic Brake/Traction Control Module (EBCM/EBTCM) goes through a self-check lasting 2-4 seconds. During this test the EBCM/EBTCM grounds terminal 34, energizing the main relay. Once the self-check is completed the main relay remains energized. This delivers battery voltage to both the EBCM/EBTCM and Brake Pressure Modulator Valve (BPMV) during vehicle operation. The constant voltage supply allows the vehicle to enter ABS mode without delay. The main relay is de-energized whenever the amber ANTILOCK indicator illuminates due to a system malfunction, causing the ABS system to shut down.

CONDITIONS FOR SETTING THE DTC
DTC C1211 sets when the ignition switch is in RUN and battery voltage is not detected at the EBCM/EBTCM terminal 3 and/or 33.

ACTION TAKEN WHEN THE DTC SETS
A malfunction DTC is stored, ABS is disabled and the ANTILOCK indicator lamp is turned ON.

CONDITIONS FOR CLEARING THE DTC
Conditions for the malfunction are no longer present and scan tool clear DTCs function is used. 100 ignition switch key cycles have passed with no malfunctions detected.

DIAGNOSTIC AIDS
Possible Causes:
- Open fuse.
- Open in CKT 242, 441, 1632, or 1633.
- Short to ground in CKT 242, 441, 1632, or 1633.
- Slow reacting or open Main relay.

A Main relay that reacts slowly due to a mechanical malfunction can cause an intermittent DTC C1211. If the Diagnostic Table instructs the technician to replace the EBCM/EBTCM, a new relay should be installed and the system rechecked before replacing the EBCM/EBTCM.

An intermittent malfunction is most likely caused by a poor connection, rubbed through wire insulation, or a wire that is broken inside the insulation. 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.

TEST DESCRIPTION
The numbers below refer to step numbers on the diagnostic table.

2. Checks for an open power feed for the solenoids internal to the BPMV.
3. Ensures that the BPMV is not internally shorted to ground.
12. Checks the integrity of CKT 1633 to the EBCM/EBTCM and the BPMV.