C1278

CIRCUIT DESCRIPTION
This Diagnostic Trouble Code (DTC) identifies a solenoid that cannot be energized due to an open in its circuitry or a solenoid that is always energized due to a short to ground in its circuitry between the EBCM and the solenoid.
An open will not allow proper ABS operation, but the short to ground simply turns ON the solenoid. A path for base brakes is still allowed once the motor rehomes and the check valve is lifted off its seat when the ignition switch is turned to ON.

CONDITIONS FOR SETTING THE DTC
^ Diagnostic Trouble Code (DTC) C1278 can set only when the solenoid is commanded off while the Electronic Brake Control Relay is enabled.
^ A malfunction exists if the Electronic Brake Control Module (EBCM) detects the right front brake solenoid valve control circuit voltage is not within specifications.

ACTION TAKEN WHEN THE DTC SETS
^ A malfunction Diagnostic Trouble Code (DTC) stores.
^ The ABS disables.
^ The ABS warning indicator turns ON.

CONDITIONS FOR CLEARING THE DTC
^ The condition responsible for setting the Diagnostic Trouble Code (DTC) no longer exists and the Scan Tool Clear DTCs function is used.
^ 100 drive cycles pass with no DTCs detected. A drive cycle consists of starting the vehicle, driving the vehicle over 16 km/h (10 mph), stopping and then turning the ignition OFF.

DIAGNOSTIC AIDS
The following conditions may cause an intermittent malfunction:
^ A poor connection
^ Rubbed-through wire insulation
^ A broken wire inside the insulation

Use the enhanced diagnostic function of the Scan Tool in order to measure the frequency of the malfunction.
Thoroughly inspect any circuitry that may cause the intermittent complaint for the following conditions:
^ Backed out terminals
^ Improper mating
^ Broken locks
^ Improperly formed or damaged terminals
^ Poor terminal-to-wiring connections
^ Physical damage to the wiring harness

TEST DESCRIPTION
2. This test checks for a short to ground in the right front solenoid valve circuit.
3. This test checks for an open in the control circuit of the solenoid.
4. This test checks for a short to ground in the control circuit of the solenoid.
5. This test checks for an open in the battery feed circuit to the solenoid.
6. This test checks for an open in the right front solenoid valve.
7. This test determines if the malfunction is caused by the Electronic Brake Control Module (EBCM).

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Part 2 Of 2:

DTC C1278 RF SOLENOID CIRCUIT OPEN OR SHORTED TO GROUND