B672

Code B672 - Cruise Vent Solenoid Circuit Problem:

Wiring Diagram for Code B672 - Cruise Vent Solenoid Circuit Problem:

CIRCUIT DESCRIPTION:

The cruise control vent solenoid receives a rapidly switched voltage 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 not vented (or it is trapped) in the servo.

Code B672 will set if the cruise is on, the brake is not depressed and the BCM output is "HI" when it should be "LO" or "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 at, not what it is actually at. An output display of "LO" means CKT 403 should be de-energized (vent solenoid off and an output display of "HI" means CKT 403 should be energized (vent solenoid "ON").

CKT 403 will be "HI" when the solenoid is energized as the BCM is providing voltage to the vent solenoid which has its own full time ground. CKT 403 will be "LO" when the solenoid is de-energized as the BCM takes away the voltage feed to the solenoid.

TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. BCM output BO01 cycles the vent solenoid. The "HI" and "LO" refer to the state of the voltage at the BCM.

2. Checks to see if fault is due to 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.

NOTE ON INTERMITTENTS:

If an intermittent code B672 is being set, manipulate the related wiring while in the output function BO01 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 3.0 seconds. Don't be fooled into thinking the spot has been found as it could be the end of the 3.0 second interval. Make sure the intermittent condition can be induced a few times.