Cruise Control - Intermittent Disengagement
No: 86/18/97/NASRef: WSM Section 57
Issue: 1
Date: 07/11/97
Cruise Control Disengagement
AFFECTED VEHICLE RANGE:
DISCOVERY (LJ) VA721658 to VA727163
VA555226 to VA558893
SITUATION:
INTERMITTENT CRUISE CONTROL DISENGAGEMENT
Vehicles between the above VINs may experience intermittent cruise control disengagement as the result of an overly sensitive switch. The switch may be energized by some daily driving conditions, such as a rough road surface.
RESOLUTION:
REPLACE OVER-SENSITIVE SWITCH
NOTE:
Vehicles in your inventory which are within the above VIN range should be inspected and the switch replaced if it fails the test procedure outlined below.
Retailed vehicles within the above VIN range should be inspected at the next service opportunity to verify switch function. Some vehicles have been inspected at the port of entry. Port inspected vehicles have been corrected if required. They can be identified by the white paint dot on the brake pedal bracket. (Paint markings other than a white dot do not relate to this inspection.)
When a customer experiences intermittent cruise control disengagement, conduct the tests outlined in the "Repair Procedure" section of this TIB. If it is determined that the switch is the cause of the disengagement, replace the switch using the procedure in the Workshop Manual.
PARTS INFORMATION:
AMR 2010 Switch
WARRANTY CLAIMS:
86.65.89/27 Time 0.15 hrs.
Inspect switch for correct operation but no replacement required
86.65.89/26 Time 0.60 hrs.
Inspect switch for correct operation and replace
Normal warranty policy and procedures apply
REPAIR PROCEDURE:
SWITCH INSPECTION PROCEDURE
When the brake light system is energized, the cruise control system will turn off. If the switch is overly sensitive, the brake circuit may be momentarily energized during some driving conditions.
Testing the brake light circuit by applying hand pressure to the brake pedal is a simple and repeatable test of switch operation which can be performed in the shop. The test will verify correct cruise control operation without the need to test drive the vehicle.
NOTE:
To perform the most effective verification of switch operation, do not depress the brake pedal when starting the engine.
1. Verify that the transmission is in "PARK" and start the engine.
2. With the assistance of a helper, verify the functional effectiveness of switch activation as follows:
^ Without touching the brake pedal, verify that brake lights are not illuminated.
^ Use your hand to depress the brake pedal to the end of the pedal free-play (about 1 mm).
^ Verify that the brake lights are not illuminated when the free-play has been removed from pedal motion.
3. With the assistance of a helper, verify the functional effectiveness of switch de-activation as follows:
^ Use your hand to slowly apply pedal pressure until the brake lights illuminate.
^ Without making any effort to pull the brake pedal upward, gently and slowly release the brake pedal until it stops at the rest position.
^ Verify that the brake lights are extinguished with the pedal at the rest position.
4. If the brake lights were illuminated under any of the following conditions, disconnect the multi-pin connector (Figure 2) and replace the switch:
^ Upon initial start up without the pedal being depressed
^ When free-play is removed
^ When the pedal is released to the rest position
5. When inspection or switch replacement is completed, identify vehicle as inspected by placing a white paint dot on the pedal bracket (located at the base of the dash kick panel directly in front of the brake pedal assembly). Apply the paint between the two hex-head bolts. (Figure 3)