| Author | Message | ||
     Bil Pletz (Bilp) New Member Username: Bilp Post Number: 2 Registered: 03-2004 |
I have a '97 Disco with an unusual ABS problem I haven't seen here, and the symptoms bring questioning looks from LR techs. Can't get into Portland dealer for three weeks, and I've sold the truck. So I'd like to get this fixed before the deal sours (want to get an '01 Disco). Any help would be greatly appreciated. Tried to find the blue plug (to jumper to read the code from the ABS light) under the driver's seat to pull the codes. My '97 only has four seat relays and four fuses. No blue plug, and the ABS Computer is under the passenger side dash. Pulled fascia plate under passenger side dash to get to ABS computer and relays. Also was hoping that the blue plug might be under there. No luck there either. Dealer said wiring harness changed in '97 so maybe that's the problem. Wiring diagram I have for the '97 doesn't show the test plug (see attached diagram). Here are the symptoms: ABS has code in memory - no blink when turning on ignition switch ABS light goes out at 5-7 mph. During this time ABS works (I tested it on the ice). After driving for awhile the ABS pump will turn on for about 5 seconds, and if you're on the brakes you can feel the pulsations. After that (15 - 30 seconds later) one of the relays under the dash on the passenger's side will cycle once. It will cycle (once) again several times at 15 - 30 second intervals. After several minutes of this, and sometimes another cycle of the ABS pump, the ABS light comes on. Here's the odd part - When this starts to occur is somewhat dependant upon the temperature - the warmer it is outside the quicker this occurs. When in the 20's it may take 45 minutes. When it's in the 70's it may take as little at 10 minutes. The longer I'm stopped with the engine running, the quicker it occurs, so I'm figuring it's dependant upon engine compartment temperature. Here's what I've done: Changed the ABS control unit (computer), replaced the ABS relay, replaced brake pedal switch. All four wheel sensors are seated, and electrical check indicates they're all working. All wiring checked and appears OK. I pulled the ABS relay, and the ABS light remains on being fed from the ABS computer (See attached wiring diagram). Two wires go to the ECU from the ABS computer (1.7VDC with ignition on, engine not running and 2.1VDC with engine running). This can be read across terminals 2 and 17 at the OBDII connector. Using a good OBDII tool (Autoxray EZ Link) no ABS codes can be read. Anybody got any ideas? I'm leaning toward a bad ABS booster unit (on the right inner wheel housing) under the hood. Can the ABS codes be read by any other OBDII units without having to have the dealer pull the code? Any other locations that the blue plug may be, or another method to pull the code? Thanks for your help. |
