DTC 46

Fig. 362 Code 46: Rear ABS Channel Will Not Move:

Rear ABS Channel Will Not Move:

Circuit Description:
This DTC is designed to detect bound-up ESB's, stuck motor or a seized hydraulic modulator. Release is commanded during initialization, the ESB should release the motor, resulting in sensed current being less than commanded current (motor is spinning freely). If the motor is not moving, sensed current will be equal to stall current.

DTC Will Set When:
DTC 46 can be set during initialization. The EBCM commands the rear motor in the reverse and forward direction to ensure the motor moves properly. If the EBCM detects a condition in which it cannot move the motor in either direction, a malfunction exists.

Action Taken:
This malfunction indicates the channel can not be moved properly. A malfunction DTC is stored, ABS 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. Ensures motor circuits are in the proper connector cavity.
2. Checks the ability of the motor to move applying hydraulic pressure to the wheel cylinders. A frozen piston or gear would result in no apply of rear brakes and a wheel that freely spins.
3. Compares feedback current to command current during apply.
4. Checks to see if hydraulic modulator is functioning properly.
5. Checks if motor can apply properly under load.
6. Isolates the malfunction to either the EBCM or a short between CKTs 1284 and 1285.
7. Checks for a shorted motor.
8. Ensures the malfunction was not due to physical damage of the circuitry.

Diagnostic Aids:
An "intermittent" malfunction in this DTC may result from a mechanical part of the system that sticks or binds.

The frequency of the malfunction can be checked by using the enhanced diagnostic function of the Tech 1.

DTC 46 may set after modulator disassembly if the modulator pistons are positioned at the bottom of their bore.

Depending on the frequency of the malfunction, a physical inspection of the mechanical parts suspected may be necessary.

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.