B673

Chart:

Schematic:

DESCRIPTION
The cruise control vacuum solenoid receives pulsed voltage signals from the Body Control Module (BCM) to control the amount of time the solenoid is energized. During the time the output is HI, the solenoid is energized and vacuum is applied to the servo.


Code B673 will set if the cruise is on, the brake pedal is not depressed, and the Electronic Control Module (ECM) output is HI when it should be LO, or LO when it should be HI. Under either of these conditions, the BCM will disable the cruise control until the BCM sees the proper output signals. These determinations are made internal to the BCM and may or may not affect the HI or LO reading displayed on BCM output BO01.

An output display of LO means CKT 402 should be de-energized (solenoid off) and an output display of HI means CKT 402 should be energized (solenoid on).

TEST DESCRIPTION
The numbers below refer to circled numbers on the diagnostic chart:
1. BCM output 13002 cycles the vacuum solenoid. The HI and LO refer to the commanded state of the voltage at the BCM.
2. Checks to see if the fault is due to the servo or circuit.
3. Checks to see if fault is due to open ground circuit or control circuit including servo solenoid.
4. Checks to see if fault is shorted servo or control circuit. If the vacuum solenoid is shorted (below 25 OHMS) BCM replacement will also be necessary.


NOTE ON INTERMITTENTS
If an intermittent Code B673 is being set, manipulate the related wiring while in the output function B002 and listen for the solenoid to cycle, (or stop cycling). This will have to be done slowly as this function cycles the solenoid on and off every 3 seconds. Make sure the intermittent condition can be induced during the on (or HI) output interval.