B673

Code B673 - Cruise - Vacuum Solenoid Circuit:

Wiring Diagram for Codes B663, B667, B671, B672 & B673:

CODE B673 - CRUISE VACUUM SOLENOID CIRCUIT PROBLEM

Circuit Description:

The cruise control vacuum solenoid receives a rapidly switched signal from the 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 supplied to the servo.

Code B673 will set if the cruise is on, the brake is not depressed and the BCM output is HI when it should be LO and LO when it should be HI. Under this condition the BCM will disable the cruise control until the BCM sees the proper output signal. These determinations are made on the circuitry internal to the BCM and may not affect the HI or LO displayed during Service Mode, as they only indicate what the BCM wants the output signal to differ from what it actually is. An output display of LO means CKT 402 should be de-energized (vacuum solenoid off) and an output display of HI means CKT 402 should be energized (vacuum solenoid on).

CKT 402 will be HI when the solenoid is energized as the BCM is providing voltage to the vacuum solenoid which has its own full time ground. CKT 402 will be LO when the solenoid is de-energized as the BCM takes away the voltage feed to the solenoid


Test Description:

1. BCM output BO02 cycles the vacuum solenoid. The HI and LO refer to the 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 BO02 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. Don't be fooled into thinking the spot has been found as it could be the end of the 3 second interval. Make sure the intermittent condition can be induced a few times.