Code 44, Front-Rear Differential Lock Control Deviation

During front-rear lock regulation phase, the monitoring circuit of ABS/AWD control unit detected excessive variations between desired value and actual value.

Possible causes include: a poorly bled lock control circuit, external hydraulic leaks, a lock cylinder that does not retain preset pressure (internal leak through load relief bore), an incorrect signal from a front or rear wheel speed sensor, faulty longitudinal lock plates or insufficient hydraulic pressure build-up at plates. The tests that follow will help determine cause.

1. Check hydraulic system for external leaks. Tighten fittings or replace components as necessary.
2. Repeat bleeding procedure for lock control circuit. See LOCK CYLINDERS & PRESSURE LINES  under BLEEDING. Check speed sensor signals by performing tests for Code 21, 22, 23 and 24.
3. Measure thickness of plates with lock measuring cylinder. See LONGITUDINAL & TRANSVERSE LOCKS  under ADJUSTMENTS.
4. Check pressure at locking moment (friction value in lock). See LONGITUDINAL & TRANSVERSE LOCK LOCKING POINTS  under DIAGNOSIS & TESTING.