I know, it threw me a curve as well.

 

Ok well I decided to take a closer look and trace the wires coming from the front wheel sensors. I should have paid better attention to the earlier post directing me to look underneath the battery tray, because under a rubber cover I found this:



I guess this is the ABS pump for the 4 wheel ABS? If so, does anyone know how I can get diagnostics from this system to help track down why the abs light is constantly on?

Thanks,
Ben

 

Ok, after some digging in my 97 OEM Service Manual I have learned a little bit about this system.
1) It does use two different control actuators, the RWAL beside the Master Cylinder and then the front ABS Pump under the battery.
2) The CAB (Controller Antilock Brake) unit for the 4WABS is beside the front wheel actuator unit. The RWAL only CAB is under the glove box insert
3) There is some diagnostic test procedures in the Dodge Chassis Diagnostic Manual (which I do not have). Does anyone have a copy even if it is close to but not the same year?

You can try to reset the unit by either removing the fuse, negative battery cable, or the 14 pin connector.

Now this is my observation and not from the OEM manual: Many failures of ABS are from faulty front wheel sensor inputs. You may want to check the wiring for problems by each front wheel, if you see any damage then replace the sensor. It appears that you have to remove the front rotor to access the bolts that attach the sensor to the backing plate. If the VSS (Vehicle Speed Sensor, on the rear axle) was the problem it would also trigger the "Check Engine" lamp and your cruise control plus OD would not work.

 

Woo Hoo, I'm absolved!

 

Thanks for the info. My cruise etc works fine, so I can assume that the rear speed sensor is ok, I've also had the battery off a couple of times since having the van so it's not just an old error that is still being shown.
I tried to 'scope the output of the front wheel sensors, but found it a little tricky to get access to the connectors (especially the right wheel sensor one which is down the front of the air-con unit) to actually get a decent connection to my probe. So, I will investigate further next time I have the wheels off.

Thanks,
Ben

 

Hello again, I'm still having ABS issues, and not sure what to check now so hopefully someone can help!

Here's the story so far:

When i bought the van, the ABS bulb was missing, and when I replaced this the ABS light was permanently on (Brake warning light operation was still normal, i.e. off unless the parking brake was activated).

I replaced the speed sensor in the differential, and the ABS light at last went off so I thought it was all good at this point. However, slowing down at junctions etc caused the ABS to activate just before the van stopped.
After some research I found this indicates a problem with either a split/dirty tone ring, or a faulty ABS sensor.

I removed the ABS fuse at this point so that I could actually stop the van properly until I had time to diagnose further. Now the Brake and ABS lights were constantly lit (as expected).

All tone rings looked fine, and after putting an oscilloscope on all 3 ABS sensors I found that the driver side front sensor was not putting out a good signal. I've just fitted a replacement sensor, and 'scoped all 3 sensors with good sinewave output now. ABS fuse has gone back in.

I've removed the battery and left for about 30 mins, but still as soon as I turn on the ignition the Brake and ABS lights stay on permanently!

I've check the parking brake switch and all is good, so I don't know what is wrong now! Do I need to get any codes reset, or should removing the battery clear everything?

Thanks for any help!

Ben

 

At the risk of asking a dumb question, did you put the fuse back it and/or make sure it wasn't blown?

 

Yes I can confirm that the fuse is ok, and was replaced!

Ben

 

Try this: On the OBD-II connector under the dash that looks like this:

Jump pins 9 and 13 for a very brief moment with the key on but engine off and count the flashes of the ABS lamp. Each code should start with one long flash followed by short flashes. Example code 9 would be one long flash with eight short flashes. The lamp will go into a loop so once you get the code or codes the cycle will keep repeating.

Post the codes here. I hope this works for the 4 wheel ABS system, I know it works for the RWAL only system.

 

I'm not sure that I have a connector that looks like that, and if I do I must be looking in the wrong place!
I seem to remember reading that '95 was the year that they changed from ODBI to ODBII, is it possible that there is a different type of connector on my van?

Thanks,
Ben