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Yep, yet another abs sensor question. Brand new to the forum so please take it easy on me. I've searched for a couple days and can't find anything new to try so now I'm asking.
I have a 2007 MDX 147,xxx miles with the the usual dash lights on from a bad wheel speed sensor. I just had the right front sensor installed and on the way home the same lights came on. I took it back to my mechanic, he scanned it and he said the left rear sensor is bad. I order a new one and replaced it myself. Of course the old one broke while I was trying to take it out so I drilled the rest of the sensor out. I installed the new one and the lights came right back on. I took it back to my mechanic, he scanned it again and said I must have gotten a bad sensor. I ordered a new one and let him install it. Same codes.
He told me I needed a new Reluctor for that axle. He said where I drilled the old sensor out my drill bit hit the axle where the sensor reads and caused a shiny spot which in turn is causing a false reading. I'm skeptical at this point.
My questions are, can the rear axles be interchanged to test this, and would the bit mark cause such a reading?
Now, I was very careful when I drilled it to not drill anything I wasn't supposed to. I may have touched it but that would have been it.
Please suggest anything I can do at this point. I'm completely lost. Thanks in advance.
 

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You need to have someone do a Scope check of the sensors. Look at all 4 of them for comparison of amplitude and missing pulses. Takes about 20 minutes on a lift.

This is a sample of a good signal on my Snap-On scope:



If you need to know who in your area is good with electronics, ask at your local parts stores. They usually know the local shops.
 

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On some cars (MDX? can't tell from 03-06 shop manual), the tone ring is pressed on axle shaft. It can corrode and come off leading to sensor codes.

Also on BMW I once had, the tone ring got dirty enough that cleaning w/ a rag stuffed in the sensor opening, turning the wheel, provided enough cleaning to remove the code.

good luck

good luck
 

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I would change the mechanic to begin with. Didn't he measure the sensor values to make sure they were in range before he gave you your vehicle back?

In the same way, measuring the sensor values will detect if the sensor is dead or not.

Can you switch the sensors to check if the sensor is dead..? You know that the first sensor works correctly, right..? Did the mechanic gave you a printout of the wheel sensor value ranges..?

AC

Yep, yet another abs sensor question. Brand new to the forum so please take it easy on me. I've searched for a couple days and can't find anything new to try so now I'm asking.
I have a 2007 MDX 147,xxx miles with the the usual dash lights on from a bad wheel speed sensor. I just had the right front sensor installed and on the way home the same lights came on. I took it back to my mechanic, he scanned it and he said the left rear sensor is bad. I order a new one and replaced it myself. Of course the old one broke while I was trying to take it out so I drilled the rest of the sensor out. I installed the new one and the lights came right back on. I took it back to my mechanic, he scanned it again and said I must have gotten a bad sensor. I ordered a new one and let him install it. Same codes.
He told me I needed a new Reluctor for that axle. He said where I drilled the old sensor out my drill bit hit the axle where the sensor reads and caused a shiny spot which in turn is causing a false reading. I'm skeptical at this point.
My questions are, can the rear axles be interchanged to test this, and would the bit mark cause such a reading?
Now, I was very careful when I drilled it to not drill anything I wasn't supposed to. I may have touched it but that would have been it.
Please suggest anything I can do at this point. I'm completely lost. Thanks in advance.
 

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Discussion Starter #7
Bluepill, he did do some kind of test and said the left rear is giving a good reading then a few seconds later drops off then right back up. Does that tell you anything? He has a really nice snap on reader thingy. He plugs a Bluetooth thingy under the dash then does the reading on a tablet similar to an iPad anywhere within 700'.

TexasHonda, I'm going to try to clean this one and I will post my results. Thanks

AC_MDX, I'm pretty limited on mechanics in my area, he's always been good in the past. I just think he has met his match on this vehicle. With that being said, if he doesn't come up with something soon a new mechanic will be found. Lol
I'll check today to see if the sensors can be switched. No, I don't know if the first sensor worked or not. It gave him the code for it being bad so I just replaced it. Lastly, he didn't give me a printout but did tell me the numbers. I don't remember what the numbers were but if it will tell anybody anything I will take it and have him run them again.
I really appreciate all the I out. Keep the ideas coming. Thank you guys!!!!!!
 

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I don't think the sensors are meant to be interchangeable, that doesn't mean they can be switched though. I just come up with separate part numbers and each description distinctively has it's own position. Maybe the brackets and wire length is what I'm guessing to be different. However visually, the front sensors do look different than the rear ones.
 

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Bluepill, he did do some kind of test and said the left rear is giving a good reading then a few seconds later drops off then right back up. Does that tell you anything? He has a really nice snap on reader thingy.
If the signal from the sensor is good sometimes and bad at other times, it's a good confirmation of a bad sensor.

Did you get a genuine Acura sensor? If you bought off-brand it's always a crap shoot. Inside the sensor is about 20 feet of ultra-fine wire that is wound around a core many times. The assembly procedure is very delicate, and certainly subject to failures if made in that Big Asian Country that sends us so much junk.
 

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Discussion Starter #10
Alpine003, I didn't get a chance yesterday to check the sensor to see if it will interchange or not. I'm hoping you're right and they will switch out even temporarily. I'll post as soon as I check.
Bluepill, it was an advanced auto special, not genuine Acura parts for sure. Maybe if they don't interchange that may they way I go next. I really appreciate everyone help. Hopefully I pin down the culprit soon.
 

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Ok guys, here's finally an update and another question.
I installed a new axle-drive shaft and nothing changed. My question is does the speed sensor read the (what I think is aluminum) ring next to where the sensor sits or does it read the (what I think is a magnet) ring on the inside of the wheel hub assembly? I noticed the magnet has some pretty deep marks from the drill bit and thought it was odd to put that there if it doesn't serve a purpose.
 

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ABS sensors usually read the splined ring on the hub assembly. Never did it on the MDX so can't say with 100% accuracy whether this applies to it as well.

 

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Here are a few pictures I pulled off the net. The darkest ring on the third picture is what I'm thinking is what the sensor reads. Im pretty sure it's a thin magnet. It doesn't have the splines like every other hub assembly has. I'm completely stumped on this one.
 

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Here are a few pictures I pulled off the net. The darkest ring on the third picture is what I'm thinking is what the sensor reads. Im pretty sure it's a thin magnet. It doesn't have the splines like every other hub assembly has. I'm completely stumped on this one.
Hmmm... Yeah maybe it's of the magnetic type like you said then. Acura maybe using a Hall effect type setup.

Did you try replacing any of the sensors yet?
 

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Discussion Starter #15
Hmmm... Yeah maybe it's of the magnetic type like you said then. Acura maybe using a Hall effect type setup.

Did you try replacing any of the sensors yet?
Yes, I've replaced the speed/abs sensor on that side twice, then the axle thinking the sensor read the ring near the end. I cleaned that ring with soap and water and made sure it didn't have any chips, dents, dings, etc.
I think I'll swap the driver side hub assembly with the passenger side and see if anything changes.
 

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Ok guys, I finally have an update. I replaced the wheel hub assembly yesterday and took her for a test drive. About 100 feet into the drive all the dash lights went off and didn't come back on. Yee Haw!
Here is an overview just in case anybody else ever has this problem So, apparently the original sensor did go bad. I had to drill it out. While drilling I hit the magnetic ring with by drill bit and took a small section out of it. I didn't know that I had did that at the time so I took it to a half wit mechanic and he determined the sensor was bad. I ordered a new sensor, he installed it and the code didn't change. He told me the "ring" on the axle was bad because when I drilled the sensor out I barely hit that ring and put a shiny spot on it. That was what was causing the code. I ordered a new axle and decided to install it myself. I pulled the alleged bad axle out and immediately saw the magnet on the wheel hub assembly had my little mishap on it. Now, I'm far from being a mechanic, I don't even qualify to be a parts changer but I knew that ring wouldn't be there if it didn't serve a purpose. I took it to the guy that had been working on it for me to get his opinion. He pretty much told be I was crazy and he had been working on cars most of his life. He knew what he was talking about. He decided to follow me to my house and prove to me that he was right. He came and installed the new axle, put the old hub assembly right back in and BAM!!!! No change. He said the ABS module was bad. At this point I was getting really fed up. I said, I'll make you a deal. You order anything you want to put on it. I don't care what or how much it costs. IF it fixed mw vehicle I'll give your money back and pay for your labor. Now, if you order something and it doesn't fix anything you just donated whatever you put on it. All of a sudden, his attitude changes and he starts saying he will start calling around and try to find out a little more about it before he changes anything else.
I had already decided I was done with this guy. So, I went straight home and ordered a new wheel hub assembly and installed it yesterday in about 30 minutes. Drove down my driveway and the Acura gods smiled down on me and now I am code free for about 60 miles now. I think I will drive by his garage and let him know what the problem was in front of everybody.
 

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I wouldn't have guessed that the tone ring was that sensitive to the drill spot that caused the problem. How bad was the drilling damage- got any pics of the damage?
 

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Thanks for the update. Based on your pic, I can definitely see how it would not function properly. Live and learn but at least you got it working now.
 
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