Code B673, Cruise Vacuum Solenoid Circuit Problem: Notes

The cruise control vent solenoid receives pulsed voltage signals from BCM to control the amount of time solenoid is energized. While time output is HI, solenoid is energized and vacuum is not vented from in servo. Code B673 will set if cruise is ON, brake is not depressed and BCM output is HI. Under either of these conditions, BCM will disable cruise control until BCM sees proper output signals. These determinations are made internal to BCM and may or may not affect HI or LO reading displayed during service mode. An output display of LO indicates circuit No. 403 should be de-energized (vent solenoid off) and an output display of HI indicates circuit No. 402 should be energized (vent solenoid on).

Circuit No. 402 will be HI when solenoid is energized as BCM is providing voltage to vent solenoid which has its own full time ground. Circuit No. 402 will be LO when the solenoid is de-energized as the BCM removes voltage feed to solenoid.

NOTE: Test numbers refer to numbers on diagnostic chart.

Test Number 1) BO02 cycles vacuum solenoid.

Test Number 2) Checks to see if fault is due to servo or circuit.

Test Number 3) Checks to see if fault is due to open ground circuit or control circuit, including servo solenoid.

Test Number 4) Checks to see if fault is shorted servo or control circuit. If vacuum solenoid is shorted (less than 25 ohms) BCM replacement will also be necessary.