B663

Code B663/B664:

Cruise Circuit:

CIRCUIT DESCRIPTION:

Code B663 will set and disengage the cruise control if the actual speed is 30 mph higher or lower than the set speed. This code is used to set upper and lower limits for operation of the cruise control system, and can be set under normal conditions if the operator accelerates, using the gas pedal, and goes 30 mph over the set speed. If the operator experiences cruise drop out with this code set but did not accelerate 30 mph over the set speed, a mechanical problem is indicated.

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

1. BCM override value BS05 displays commanded servo position. The commanded range is normally from 0 to 99%. If the servo will not go to full stroke, the vacuum supply, servo, or vacuum brake release circuit is leaking.

2. Checks to see if vacuum leak is due to brake release valve and circuit or servo and source vacuum.

3. Checks to see if vacuum leak is due to vacuum source or servo.

4. Checks to see if fault is due to intermittent or slow vacuum leak.

5. Checks to see if fault is servo or brake vacuum release circuit.

NOTE ON INTERMITTENTS:

If code B663 is setting intermittently make sure owner is not overrunning set speed by more than 30 mph. Check vacuum source and brake release vacuum lines for proper connections or slow leaks.

CODE B664 CIRCUIT DESCRIPTION:

This code will set and disengage the cruise control if vehicle acceleration exceeds a preset rate calibrated in the BCM. This could occur on slippery pavement or for some mechanical problems such as transmission slippage. Under these conditions, this code is normal. It should be cleared and the owner should be advised of this.