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ABS problem '300m scan results

5K views 4 replies 3 participants last post by  ImperialCrown 
#1 ·
Using an Innova 3160 scan tool, the tool tells me there are no powertrain DTC's or freeze-frame data presently stored in the car's computer. Going to the ABS part of the enhanced DTC menu tells me there are 5 stored codes, all of them being id'd as "Cxxxx":

01 Lf Wheel Speed/Signal failure
02 Lr Wheel Speed/Signal failure
03 Rr Wheel Speed/Signal failure
04 Hydraulic pump circuit failure
05 Valve Power Feed Failure

Given the above, it seems odd that there is no code for Right-front wheel signal failure given the problem with the other 3 wheels.

And just an aside, when I try to look at the Transmission DTC's, the tool tells me "unable to establish link with vehicle computer". (the tool gives a menu of different car makers and I chose Chrysler/jeep).

I pulled and checked 2 fuses in the engine compartment that are labelled as ABS-related, and both fuses check ok with a meter. The ABS unit is near the windshield fluid reservoir - yes? And it has at least 2 connectors (1 with lots of wires, the other with just 2 wires - yes?) and the connector with 2 wires is for power - yes? I've pulled out and pushed back the 2-wire connector and that didn't change anything. If that is for 12-volt power I'll pull it and see if I get power there. Otherwise I guess I'll have to try to disconnect and re-connect the cable with lots of wires.

I've noticed that the ABS and Trac control lights usually stay lit after I start the engine, but once in a while they will go out before I start driving the car but will come on again after driving a short distance (I think when I hit 23 km/hr when I usually hear the click from the ABS test, which I'm not hearing since this started).

The tool can (I think) erase the ABS code - is that something I should try? Or should I look at wiring problems first? Maybe there is an un-reparable problem with the ABS unit?
 
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#2 ·
Most online reviews are favorable for this scan tool, but there are also some disappointments of it not reading certain modules on certain vehicles. I have had problems with some 'generic' scan tools where trying another scan tool will get me the information I need. A 'universal' scan tool would be nice but very expensive.
If you can borrow another scan tool, I would try it.
I don't know why you don't have a RF wheel speed sensor fault, but putting that aside, the loss of 'valve power feed' will likely cause a multitude of other faults. You probably only have one single problem with the ABS and this is the one. It would be highly unusual for all those other items to fail at one time.
The Chassis diagnostic procedures book will give you an orderly and detailed troubleshooting plan of attack for getting to the root cause. See p. 11. A simple schematic, connector pinouts and wire colors are in the back of the book:
http://oskin.ru/pub/chrysler-dodge/manuals/Service Manuals/2002_LH_300M_Concorde_Intrepid/02lhec.pdf
 
#3 ·
I've come across a comment in another (non-automotive) forum where someone with a MercBenz had an ABS light come on, didn't think it was an emergency condition, but after a few hours of driving the car died because the problem was really the alternator. Any ideas if my ABS system is being bothered by an alternator or voltage-regulation issue? (I haven't looked into the ABS situation yet, btw).

In a 300m, how does the instrument panel alert the driver to a bad alternator / bad voltage issue? Is if via the Check-Engine light? Or is there a dedicated light for that somewhere on the panel?
 
#4 ·
The battery light would go on if it wasn't charging but there's nothing for over-voltage.

My battery just died on my car, so I did a test of my charging system... with a fully-charged battery, voltage was 14.4,14.5 at idle, with lights on and off (no difference). Revving showed it go up to as high as 14.6. Anything too much higher than these may be suspect.
 
#5 ·
See p. 27 and 29 in the ABS diagnostics book link I provided above for system 'Undervoltage' and 'Overvoltage' fault codes. I would think that if you were having charging system issues, you would have more symptoms than just an ABS light on.
 
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