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sprinkles08, Chrysler/Dodge/Jeep master tech
Category: Dodge
Satisfied Customers: 22675
Experience:  ASE Master and Advanced Certified, Chrysler/Dodge/Jeep Master Certified, Trans and Hybrid Specialist
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2005 Dodge Caravan: ABS as a rear wheel speed sensor

Customer Question

I have a 2005 Dodge Caravan that the ABS light is on. We have taken it into a mechanic and at first they diagnosed it as a rear wheel speed sensor. As they got looking at it, they concluded that that was not the issue and now they believe it is the "Anti Lock Brake Controller". I'm not sure I buy into it and the question I have is....Would the wheel speed sensor on the left rear wheel work on the right side if they swapped those out? I guess what they did was they swapped the left to the right and the right to the left and then cleared the computer and then the ABS light came back on again with it indicating that it was the right wheel sensor. Just curious what your thoughts may be?
Submitted: 7 years ago.
Category: Dodge
Expert:  sprinkles08 replied 7 years ago.

Hello and welcome to JustAnswer!


Is it always the right sensor that sets the code? Or does the fault code set for the opposite side when the sensors are swapped around?

Customer: replied 7 years ago.

You know I don't recall the mechanic indicating that it triggered the fault sensor for the left side. All that he told me was that they swapped them out and the right side wheel speed sensor triggered the light to come back on. They diagnosed the connectivity for the wires and beleive the fault is on the Anti Lock Brake controller where the wires from the right rear wheel and the brake controller. The van only has 35,000 miles on it. Also I will note that on last friday we were involved with a minor accidient where I had to slam on the breaks and that is what started the whole thing with the ABS light going on.


Hopefully that helps.

Expert:  sprinkles08 replied 7 years ago.

It would be highly beneficial to know if the fault code goes with the sensor. If the code always sets for the right side then you know it can't be the sensor. If swapping the sensor from one side to the other changes the fault code, then you know the sensor is bad.


It's hard to say what is going on without seeing it and what actual code is setting. If it's setting a sensor circuit code, that means the circuit from the processor in the ABS module to the sensor is open. This could be the module, sensor, or wiring in between. If it's setting a speed sensor failure code then you know the electrical circuit is ok and something else is going on.


If it's a circuit code it can only be the module, wiring, or sensor. If swapping the sensor doesn't change the code, then it's wiring or the module. They need to load test the wires to the sensor in this case, not just checking them for continuity with a voltmeter.


If it's a signal failure code then it could really still be any of these things, but the wheel bearing is a possibility too. The tone wheel that the sensor runs off of is inside the bearing, if the bearing is loose then it will change the air gap between the sensor and tone wheel and affect it's signal.




If swapping the sensor to the other side of the van changes the code, the sensor is bad.


If swapping the sensor doesn't change the code then rule out the sensor. It could be the wheel bearing, wiring or module. If the bearing is tight it should be ok.


If it comes to this point I would recommend load testing the wiring with a headlamp or fog lamp bulb. They should be familiar with this procedure and may have already done it. If the wiring checks out and so does the sensor and wheel bearing, then the module is going to need to be replaced.

Customer: replied 7 years ago.

Ok, that all makes sense to me. I do have a couple more questions.


1. The traction control was also automatically set to off and when I push that button, it does not turn back on. So in doing that, I'm assuming that is tied in with the ABS braking controller?


2. We are planning on taking a long road trip this weekend. Would you recommend driving the vehicle or getting it fixed immediately?

Expert:  sprinkles08 replied 7 years ago.
Yes, traction control is just a function of the ABS system. It uses the same sensors along with the ABS pump and hydraulic control unit. Any time the ABS light comes on it will disable ABS and traction control functions and both warning lights will come on.

As far as driving it that would have to be a decision you would make. This won't affect base braking at all, you will still have normal brakes. You won't have any ABS functions though, so if you hit the brakes hard enough to lock them the ABS wouldn't come on like you are used to.
Customer: replied 7 years ago.
Are you aware of any other side effects that this could cause. Issues with speedometer or any other funky stuff?
Expert:  sprinkles08 replied 7 years ago.
No, this won't cause any other problems other than rendering the ABS inoperable. The speedometer gets it's signal over the PCI communication bus, the signal originates at the output speed sensor on the trans, then through the trans controller and then broadcast over the bus.
Customer: replied 7 years ago.

This is more of a curiousity question. We purchased the van brand new, again it only has 35000 miles on it. This is the first time that the ABS light has come on and I'm wondering if by slamming on the brakes during the accidient would cause these items to go bad or is it just "coincedence"?


Also are the left and right wheel speed sensors interchangeable? I vaguely remember a conversation with the parts guy at our local dealership stating that one costs more than the other and now I can't remember if that was for a left vs. right or if that was comparing two other sensors.

Expert:  sprinkles08 replied 7 years ago.
It's hard to say if slamming on the brakes is what caused it. It shouldn't have caused it, but I wouldn't say that it didn't cause it for sure.

I believe the left and right sensors are the same part number but I'm not positive. The only difference may be the length of the wiring if there was a difference. The actual sensor itself and the electrical connector are the same, and swapping them is definitely a feasible testing option. I've done this myself on occasion, swapping the sensor side to side and then watching the signals on a scan tool.
Customer: replied 7 years ago.

So if I was a mechanic and at first I told you it was the wheel speed sensor, then you ok the repair. While performing that repair, I discover or conclude that it really isn't the wheel speed sensor and perform the diagnostic steps I mentioned earlier. Then I indicate the I beleive it is the "Anti Lock Brake Controller" that needs to be replaced. What would your immediate response be?


And lets say you are satisfied with the answer or you buy into my reasoning and we go ahead and replace the controller and it still doesn't correct the problem. What would you expect the next step to be?

Expert:  sprinkles08 replied 7 years ago.

I can say for sure that I wouldn't be happy to find that I needed a module when I was first told it was the sensor. These sensors do fail pretty often, so they may have just read the fault code and didn't go through a lengthy diagnostic.


It shouldn't get to the point that the controller is replaced and that not fix it. It's too simple to diagnose correctly. Swap the sensors, and if that doesn't change it then the wiring needs to be load tested. Just checking continuity with a voltmeter isn't enough, too much money is at stake! If the wiring does load test fine then it would then be time for a module.

Customer: replied 7 years ago.

Thank you for answering my questions. You have been very helpful and I appreciate it. I think I'm done asking questions regarding this unless I can keep the ticket open and get the codes the mechanic pulled to give you or another mechanic more accurate information? I wouldn't be able to do that until tomorrow.


One real quick off the cuff question. lets say you have a 1995 nissan altima. 135,000, engine runs good, body is in decent shape, a little rust by the rear driver side door and the tranny goes out. Would you spend $2,000 for a new tranny or ditch the car and put the money towards something newer?

Expert:  sprinkles08 replied 7 years ago.

The question never closes, you can come back and reply at any time in the future if you need more help with the ABS problem. Hitting the Accept button doesn't cut off communication and I woudln't leave you hanging. I'm a full time tech and work during the day, but if you reply while I'm offline I'll get back to you as quick as I can.


I'm not a Nissan expert and I'm not real familiar with the longevity and such of the Altima so that makes it a tough call. I tend to keep vehicles forever (my car has 253,000 miles on it), but I don't have to pay for labor for repairs either! $2,000 seems like a bit to spend on the repair, but then again it's cheaper than a new car payment too, and if the rest of the car is in good shape and has been taken care of I would bet it has plenty of life left in it. A used trans would be another way to go, which is normally quite a bit cheaper than a new or remanufactured one. If you do go with a used one I would recommend making sure you get something with a warranty.