98 Pontiac Trans Sport/Montana C1242 issue. Help!

[Bush072086]

Hey everyone! I have just recently purchased a 98 Trans Sport for my wife, and I have fixed all the issues it had minus the ABS/TRAC issue. I pulled the code at work with my scanner and I have a C1242 code (ESB slipping). Now I have never owned a GM product before so hopefully someone can clue me in on this problem. When I bought the van it had rear sir shocks that were blown. I have since replaced them with cheaper normal shocks. The ride height seems normal to me but someone at work suggested it could be the lack of the air shocks. When I first turn the car on the lights are off. Sometimes when I hit the brake for the first time the lights come on immidiately, and other times I can drive it about 2 blocks and then it comes on??? Any suggestions on where to start? Thanks.

 

[ianmcdca]

This is not a problem with the shocks. It`s a problem with your ABS system. I`m not sure how to fix it but heres something for you to read through. Hope it helps.

Sounds like the ABS unit itself....not sure.


Circuit Description
The system relay is energized when the ignition is ON. The system relay supplies voltage to the solenoid valves and the pump motor. This voltage is referred to as the system voltage.
The EBCM controls each solenoid valve by grounding the solenoid.
The EBCM controls the pump motor by grounding the control circuit. The pump serves 2 purposes:


•Transfers brake fluid from the brake calipers to the master cylinder reservoir during pressure decrease events.
•Transfers brake fluid from the master cylinder reservoir to the brake calipers during pressure increase events.
Conditions for Running the DTC
C1242


•The system voltage is greater than 8.0 volts.
•The system relay is ON.
•The pump motor is commanded OFF.
C1243


•The pump motor is ON for at least 0.3 seconds.
•The system relay is ON.
Conditions for Setting the DTC
C1242
The voltage across the pump motor is between 1.7 - 10.2 volts for 2 seconds.

C1243
The pump motor is stalled or turning slowly.

Action Taken When the DTC Sets
If equipped, the following actions occur:


•The EBCM disables the ABS/TCS for the duration of the ignition cycle.
•The DRP does not function optimally.
•The ABS indicator turns ON.
•The Traction Off indicator turns ON.
•The message center displays the Service Traction System message.
Conditions for Clearing the DTC


•The condition for the DTC is no longer present and you used the scan tool Clear DTC function.
•The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.
Diagnostic Aids
The pump motor is integral to the BPMV. The pump motor is not serviceable.

Test Description
The number below refers to the step number on the diagnostic table.


5.Tests the ability of the EBCM to control the pump motor. If the test lamp illuminates, the pump motor circuit within the EBCM is good.