PDA

View Full Version : ABS module rebuild


supercruise
05-04-2007, 02:35 AM
Has anyone had a rebuild of their Bosch 5.3 ABS controller? Dealer wants $1400 to install a new ABS module in my 99 Cobra but I see there's a number of places that rebuild the units for $200 or less. The ABS light is constantly on and the dealer can't get any codes off it therefore the diagnosis of replacing the controller. There's an abundance of Bosch 5.3 rebuild services on eBay and the net which causes me to believe that it's a common problem. Anyone out there have any ABS experience or advice for me and my 99?

ausie
05-04-2007, 07:55 AM
Before you end up tearing it all apart for service or having an expensive repair bill, I would at least take some time to see if there is something other than the ABS module contributing to the problem.
Look in your manual if you have it and try to locate the fuses for the ABS system. If none are listed, it may be part of a GEM control module. If all of the fuses are in good shape, the next step would be to inspect the wires and sensors for damage. If you find any damage to the wire cables of the sensors that could be the cause for malfunction of the ABS.

Rear sensors on the IRS Cobra's are located on the output shafts of the Differential (the toothed gear looking extension on the output shaft is used by the sensor, so the sensor has to be mounted close to that). I believe the front sensors sit behind the rotor. Once you find all of the sensors, try to follow the electrical cables back to the ABS module. Or just inspect the connections on the ABS module itself. One area to be concerned with is where the headers come close to the electrical lines of the ABS sensors. If all looks good (i.e. no damaged cables, electrical conectors to the ABS system are not loose, then I would assume the module is bad. The next part would be to inspect the connection between the ABS and the wire harness. Try to locate the connector that connects the ABS system to the PCM or GEM unit.
I would at least follow the basic path first before replacing or refurbishing the ABS in case it is just a wire or connector issue which would cost less to repair than spending alot of money and find the same issue.
When inspecting the connectors, look for loose wires if they are exposed on the back side of the connector. IF the sealant is no longer sealing the wire, the pins can corrode causing poor connection. IF the wires are loose, it is possible the associated pin in the connector is not making good contact.

Another issue that will play havoc with the ABS system is a difference of tire diameters between the front and rear. How much difference will cause an issue is hard to tell. If the overall diameters of the rear are larger than the front, the rear tires will rotate in lower revs per mile than the smaller front tire. This becomes a problem when comming to a stop since the system will think that the rear end is locking up.