ABS lamp do I need a Bosch Hammer to reset

[ehcsrop]

Hi

Edited June 18, 2011 by ehcsrop

[berny]

Hi all

I am an ex main dealer Porsche tech (don't hang me for that), I mainly worked on 997, 996, Cayenne, Boxster, not much older stuff. I have been looking at a C4 964 for a mate. His ABS lamp, caution lamp and (excuse my ignorance) looks like a 4wd lamp? They were flashing on over bumps etc. I stripped out the front ABS sensors and cleaned them up, tested the sensors they are putting out ac volts. I checked continuity of the wiring looms for the front sensors up to the inside of the wings. I cleaned up the earth connections at the sensor and on the inner wings. I checked the ABS brain plug for seating along with the ABS relays all 3. The brake fluid level is OK. I refitted everything and now the lights are on constantly? I was doing an oil change too so had the front of the car jacked way up high and running the engine to warm it up prior to emptying the oil tank. If I have unplugged the sensors with the engine running would that cause the warning lamp to remain on? On this system do the faults have to be cleared with a Bosch Hammer etc or does the fault memory automatically self clear (volatile or non-volatile)? I tried disconnecting the earth from the battery for a few minutes already.

Any help greatly appreciated. I may be able to help you guys with the newer stuff !!

Many thanks

Hi If you drive the car it should put the light out if all is ok!

[ehcsrop]

Hi all

I am an ex main dealer Porsche tech (don't hang me for that), I mainly worked on 997, 996, Cayenne, Boxster, not much older stuff. I have been looking at a C4 964 for a mate. His ABS lamp, caution lamp and (excuse my ignorance) looks like a 4wd lamp? They were flashing on over bumps etc. I stripped out the front ABS sensors and cleaned them up, tested the sensors they are putting out ac volts. I checked continuity of the wiring looms for the front sensors up to the inside of the wings. I cleaned up the earth connections at the sensor and on the inner wings. I checked the ABS brain plug for seating along with the ABS relays all 3. The brake fluid level is OK. I refitted everything and now the lights are on constantly? I was doing an oil change too so had the front of the car jacked way up high and running the engine to warm it up prior to emptying the oil tank. If I have unplugged the sensors with the engine running would that cause the warning lamp to remain on? On this system do the faults have to be cleared with a Bosch Hammer etc or does the fault memory automatically self clear (volatile or non-volatile)? I tried disconnecting the earth from the battery for a few minutes already.

Any help greatly appreciated. I may be able to help you guys with the newer stuff !!

Many thanks

Hi If you drive the car it should put the light out if all is ok!

What faults would cause the lamps to stay on right from start up?

[ralendrum]

This problem sounds very similar to the one I had ( Stray Voltage). My explanation may not have been the greatest but my problems started when I "Tuned Up" my engine. I had the ABS, PDAS (four wheel drive looking) and CEL light all on. When I drove the car I would get the red lights flashing on and off when hitting bumps and eventually the CEL would flash. When the CEL flashed the engine would die and then come right back on. I went through all of the ABS and braking checks. I have the Durametric program and had all kinds of codes about controller being bad, relays being bad. I eventually read somewhere that the ignition system could cause the same problems.

I started playing around with the coil/ignitor plugs and found that one of the ignition circuits was the cause. To make a long story short I narrowed it down to the lower spark plugs. I removed the wires and checked resistance, all good. I removed the plugs again and checked gap, still all good. I plugged everything back in and started the car. It runs like a top. I have since taken it on many drives and have never had a light come back on nor a miss from the engine. I am guessing that one plug wire must not have seated and was arcing to ground. This scrambles the computers (ABS and ECU) to give me the problems. I know it sounds too simple but I would look into the ignition end of things.

Bob