Powertrain control module?

[Black03Limited]

Well, took the liberty to a shop to install a new connector for the rear speed sensor. No luck. Still getting the ABS and brake warning lights and speedo is still acting funky. The mechanic said he thinks it may be the module that controls the ABS?? I am assuming its the Powertrain control module? Or is it the Body control module?

This is after a new connector, and a new sensor and changing the rear differential fluid out.

I do not understand. The mechanic says he does not believe the tone ring is bad either because when he spins the wheels, he seems to be getting a constant reading from the rear sensor. I dont understand what else it could be? Of course this is just my luck. It cant be anything 'normal' or easy.

What do you guys think? I am at my wits end and now find out i could need a new control module that could cost up to 1000 dollars?? I cant drop that kind of cash without being 200% sure its going to do the trick.

 

[tjkj2002]

You know there are 2 more ABS sensors,1 on each front wheel,that could be the ABS problem.

 

[Black03Limited]

Yeah, the mechanic said that there are the two in the front and the one in the back, but he is only pulling a code for the one in the back still. And even if it were one of those sensors, the speedo is still not working. So is it even possible the PCM or BCM could be not communicating correctly with the rear speed sensor?

Or would it be worth my while to go ahead and replace the two front sensors before i try anything else? Would the two front ABS sensors cause speedometer problems if they didnt work correctly?

 

[tjkj2002]

Yeah, the mechanic said that there are the two in the front and the one in the back, but he is only pulling a code for the one in the back still. And even if it were one of those sensors, the speedo is still not working. So is it even possible the PCM or BCM could be not communicating correctly with the rear speed sensor?

Or would it be worth my while to go ahead and replace the two front sensors before i try anything else?

I'd be getting a new mechanic,there's still a short somewhere in the rear wiring or the sensor is not placed correctly,possibly the tone ring in the diff is bad.For the rear sensor the Yellow wire is the 12 volt supplied voltage wire,if there is a problem with the voltage going to the sensor then the BCM is bad,if there is not the problem is elsewhere.

 

[Black03Limited]

What do you mean by the sensor not being 'placed' correctly? I was wondering about if there was still something wrong with the wiring back there. But since he replaced the rear connector, i dont know how there could still be anything wrong with that sensor back there.

I figured he would have checked all the continuity on all the wires. I wonder if he has checked the connector wires?

And one more question, not sure if you know, but what exactly would cause the tone ring to be bad? Would there be broken teeth on it? Should i have them check that?

Sorry about all these questions. Please bear with me i know its probably getting kind of annoying seeing these threads from me, but i just want this to be over without spending a fortune. Thanks so much.

 

[tjkj2002]

What do you mean by the sensor not being 'placed' correctly? I was wondering about if there was still something wrong with the wiring back there. But since he replaced the rear connector, i dont know how there could still be anything wrong with that sensor back there.

I figured he would have checked all the continuity on all the wires. I wonder if he has checked the connector wires?

And one more question, not sure if you know, but what exactly would cause the tone ring to be bad? Would there be broken teeth on it? Should i have them check that?

Sorry about all these questions. Please bear with me i know its probably getting kind of annoying seeing these threads from me, but i just want this to be over without spending a fortune. Thanks so much.

It could be easy to have a damaged tone ring,pull the rear diff cover cover and look at the tone ring for any missing teeth.

 

[Black03Limited]

I think i will ask them to do that. But first, i think i will ask them to take a multimeter and check continuity from the speed sensor connector to whereever the harness connects to the computer. I would rather rule out the wire connection and even the less likely tone ring before i ordered a new BCM for it.

Thanks tjkj.

 

[Black03Limited]

Well, last week i had the mechanic check the continuity of the speed sensor wires and pull the the cover off of the rear differential to check the tone ring.

I stopped in today and asked what he had found, and he said the wires were fine and getting voltage. He even had someone wiggle the wires while he had the multimeter hooked up to it to see if that would make a difference, but it didn't. He also said the tone ring was fine and the inside of the differential looked great. So he filled it back up with synthetic 75w-90 and some limited slip additive. He said the ABS and brake lights were still on.

So i told him thanks for checking, payed him for the 2 hours of labor, the connector, the oil and additive (264 dollars total) and took the key to the jeep.

Upon unlocking the door and starting up the jeep, after the dinging stopped, sure enough, the ABS light and brake warning light came on. No engine light, though. So i just shrugged, started to drive and less than a minute down the road, looked at the dash and all the lights had gone out! The speedometer and odometer were working as well! I could not believe it! About 20 miles or so were put on the jeep since picking it up and the lights have not come back on. I have had no other issues, either.

I dont know what exactly it was, or what exactly fixed it, but i am not going to question it. This was very weird to say the least.

Anyway, problem resolved. Thanks for all your help with this annoying issue!

 

[JeepJeepster]

Electrical issues(shorts) come and go.. Keep an out for it to come back..

 

[Black03Limited]

dont say that! because i have no idea what else it could possibly be! Thats why im going to stay positive and act like its not going to return