Central Control Module (CCM)

Diagnostic Chart:

CIRCUIT DESCRIPTION

CKTs 1294, 1295, and the Variable Effort Steering (VES) solenoid actuator are used to conduct the pulse width modulation for the variable effort system. The CCM has the ability to detect a problem in the VES circuits.

DTC WILL SET WHEN

With ignition in "RUN," the VES function is "OFF," and CKT 1295 is not grounded by the CCM.

The CCM checks for a fault once each ignition cycle, and will set a DTC if the fault exists. DTC 27 will set if voltage at terminal "C13" is greater than 3 volts (153 A/D counts).

ACTION TAKEN

DTC 27 will set. If CKTs 1294, 1295, or the Power Steering (P/S) pump and Electronic Variable Orifice (EVO) actuator is shorted to battery, the CCM will completely disable the VES system. If a fault is detected, the power steering will return to normal.

DTC WILL CLEAR WHEN

DTC 27 will clear if the fault goes away for 2 or more seconds.

DTC CHART TEST DESCRIPTION

Number(s) below refer to circled number(s) on the diagnostic chart.

1. This test checks for a shorted VES solenoid actuator.

2. This test checks for a short to B+ in CKT 1295.

3. This test checks for a short to B+ in CKT 1294.

DIAGNOSTIC AIDS

If the DTC is a history DTC, the problem may be intermittent. Try performing the test shown while "wiggling" wiring and connectors; this can often cause the fault to appear. Check for intermittent shorts to in the wiring from the CCM to the power steering pump and EVO actuator.

A Tech 1 can be used to monitor the CCM VES output.