C1247

CIRCUIT DESCRIPTION
Diagnostic Trouble Code (DTC) C1247 detects a stripped nut or gear assembly during initialization. During the homing sequence, the piston should reach the top of the bore. Then the ABS motor stalls. If the ABS motor does not stall, the ABS motor must be spinning with little or no resistance. This indicates a nut/screw or gear malfunction.

CONDITIONS FOR SETTING THE DTC
^ Diagnostic Trouble Code (DTC) C1247 can only set during initialization.
^ A malfunction exists if the feedback current is less than the command current for a specified period of time.

ACTION TAKEN WHEN THE DTC SETS
^ A malfunction Diagnostic Trouble Codes (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 if the conditions exist in a mechanical part of the system:
^ Sticking
^ Binding
^ Slipping

Use the enhanced diagnostic function of the Scan Tool in order to measure the frequency of the malfunction. Diagnostic Trouble Code (DTC) C1247 may set after modulator disassembly if the modulator pistons are positioned at the bottom of the modulator piston bore. If DTC C1247 only occurs once and DTC C1256 also occurs, refer to DTC C1256. If intermittent and enhanced diagnostics shows this DTC occurs during ABS, refer to DTC C1256.
Depending on the frequency of the malfunction, a physical inspection of the mechanical parts suspected of causing the malfunction may be necessary.
Clear the DTCs after completing the diagnosis. Test drive the vehicle for three drive cycles in order to verify that the DTC does not reset. Use the following procedure in order to complete one drive cycle:
1. Start the vehicle.
2. Drive the vehicle over 16 km/h (10 mph).
3. Stop the vehicle.
4. Turn the ignition to the OFF position.

TEST DESCRIPTION
3. This test checks for motor movement by comparing the motor feedback current to the motor command current during apply.
4. This test checks for motor movement by comparing the motor feedback current to the motor command current during release.
5. This test checks for piston movement.
6. This test checks for excessive resistance in the left front motor high circuit.
7. This test checks for excessive resistance in the left front motor low circuit.
8. This test checks for the proper left front motor resistance value.
11. This test checks for proper operation of the motor pack.
12. This test checks for proper operation of the hydraulic modulator.
14. This test determines if the malfunction is caused by the Electronic Brake Control Module (EBCM).

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DTC C1247 LEFT FRONT ABS MOTOR FREE SPINS