had my99 impreza in the dealers for a abs light which comes on after about a mile and stays on, they put it on some machine and they came up with nothing! the person who normally looks after the tech side is on holiday for 2 weeks so cant do anything till after then anyone got any good ideas of which could cause a fault in the abs that thier diagnostic tools cant detect

 

If the ABS light comes on the ABS ECU should have a fault stored I would presume. Presumption and Subaru dealers don't always mix. Apparently the Select Monitor can interrogate the ABS ECU.

 

their diagnostic equipment is saying there is nothing wrong with the car, there is no fault codes stored

 

If they took it out and drove it and the ABS light is on the ABS should report a fault code, SURELY? This is basic ABS diagnostic facilities, and certainly the Bosch ABS systems do this. Not sure who makes the Subaru one.

[Edited by john banks - 12/27/2002 7:27:15 PM]

 

check the wheel sensors and the wires that run from them to the car... check to see if they arent worn through etc..

David

 

have already put different sensors on the car

 

sounds like a bad sensor or a reluctor missing a tooth, did you recently do any brake work??

jeremy

 

If the light came on, there will be a fault code stored (unless you have an intermittant ground short fault on your light circuit between the light and the ECU terminal). When the light comes on again, drive at a speed of about 20 MPH in a safe place and stamp on the brake pedal. If the pedal pulsates then your ABS is fine and the fault is on the light circuit. If the pedal does not pulsate, then the ABS ECU has disabled the system because it has indeed detected a fault. Flash codes (fault codes represented by flashing of the ABS warning light) can be extracted by shorting together the relevant terminals of the DLC3 (diagnostic plug under the dash). Your dealer should have tried this after the scan tool blanked. The reason a scan tool returns no code is often because previous technicians have extracted flash codes by shorting these terminals together (terminal TC and CG) with a split pin or something equally as subtle. This spreads the terminals and prevents communication with the scan tool.