1999 Vanden Plas

I believe my ASC system is malfunctioning and engages at random times intermittently thus resulting in a loss of acceleration. So I push the 'asc' button to turn it off but, I have to do this every time I start the car.

Is there a way to disable the asc system permanently via pulling a fuse (I didn't see one) or taking the button out and rewiring it (if so how)?

 

A suggestion: I would try and find out why it's happening.
This could be something as simple as a wheel sensor that can be replaced. Or, it could be an indicator of a more serious problem in the rear end assembly.

Closing your eyes and hoping it goes away may sound good, but in the long run, you will probably end up paying for it.

Just my advice.

 

I should clarify that it only happens when first accelerating in drive (then only once) after sitting overnight i.e its very intermittent. After that it's OK, but it never trips any codes. I've cleaned the wheel sensors and rebuilt both the ABS module and throttle body so I'm at loss why it happens.

I know there is a problem somewhere but, I don't have the money/time to have a professional with a dealer level scan tool figure it out. So the "easy" way of messing with button will suffice. Regardless thanks for the input.

 

Maybe a marginal battery.

 

Hi PoorJagOwner,

Just to be sure we understand, when you say the "ASC system engages at random times intermittently thus resulting in a loss of acceleration," do you mean that you feel the brakes operating at one or more wheels, or do you mean that a warning lamp illuminates on the instrument cluster?

Does the Restricted Performance warning appear on the IC?

Problems with the ABS/ASC system are commonly caused by dirty or faulty wheel speed sensors, bad solder joints on the circuit board in the ABS module (not only on the two large pins for the pump, but on solder connections for other components on the circuit board as well), corrosion on electrical connectors or ground points, or an intermittent break in a wheel speed sensor wiring harness.

The codes flagged for the ABS/ASC system mostly have a C-prefix (Chassis), so it might be worth the money to at least have a good independent mechanic with the proper scanning system to scan the codes to narrow down your diagnosis. I am attaching the ABS Diagnostic Trouble Codes Summaries manual.

You can test the wheel speed sensors and their wiring at the main connector at the ABS module. Most of the good sensors I've measured fall into the range of 1200 - 1600 ohms (1.2K - 1.6K).

While reading the resistance of each wheel speed sensor and its wiring, flex and manipulate the wiring from the sensor to the electrical connector for its pigtail harness to see if the resistance jumps to infinity, indicating a break at the point of flexure. It is usually possible to repair the harness by cutting open the outer insulation, splicing and soldering the broken wire, and sealing it up with heat-shrink tubing, liquid tape and/or electrician's tape. I am attaching a sheet from Gus at jagrepair.com that shows the terminals of the ABS module connector at which you can measure each sensor and its wiring harness:

It would also be worth cleaning all the electrical connectors and ground points associated with the ABS/ASC system. You can find their locations in the Electrical Guide, which I am also attaching.

Please keep us informed.

Cheers,

Don

 

I'll try that out soon, thanks for the resources.