2001 Grand Prix PROBLEMS - hesitation

Hey guys, I am new to the forum, so go easy on me ;-) I have an 01 Grand Prix GT, auto trans. and 116K miles. The ABS light is constantly on even after changing the front wheel bearing (the one the dealer said was bad) thinking it was the speed sensor. Are the wheel speed sensors located in the bearings or is the sensor located outside the bearing? If so where could i find it? The GP has also started a weird hesitation. It seems to happen more as I accelerate, but even happens unexpectedly on a level surface with the cruise set. Does not do it in park or neutral (that I've noticed), and after going through the gears manually while driving it seems to do it in second gear after coming out of first. I have started to fear a tranny problem. I hope not though. I hope that there is possibly a simple fix for this. I have already dropped $200 for a mechanic to just clean the MAF and tell me it was fixed, discovering that after driving out the garage it was still doing it. They couldn't find any codes or other issues. Has anyone ever seen or heard of this before?

On the hub bearing question, the wheel speed sensor is part of the hub bearing and cannot be replaced separately. As far as the ABS light, it could be the other hub bearing (although hubs usually cause both the Trac-off and ABs lights to illuminate) or a problem with the ABS system itself. I would have the car scanned with an ABS capable scanner and see what comes up.

On the hesitation/MAF issue, try disconnecting it and drive it that way. If it runs better with the MAF unplugged, then it's bad and you need a new one.

That's funny, I didn't think about that. The mechanic said it ran fine with the MAF disconnected. DUH. How far from the air filter housing is the MAF located? Is it easily accessible from the top of the engine?

Here's a link to the tips and maintenance sub-forum that shows the location of various sensors, including the MAF sensor. The picture shows the engine with the plastic cover removed so you can see the components.

http://www.automotiveforums.com/vbulletin/showthread.php?t=746374

Wow, thanks!

Unplugged the MAF and it runs great. I am planning on replacing it soon. Also: how are the Cardone brand sensors? remanufactured or new? I am liking the 70.00 core charge.

I'm not a big fan of Cardone electronics. They do a great job on mechanical parts (brake calipers, axle shafts, etc...) but their electronics (MAF's and ECM/PCM's are not very dependable.

Rich, you forgot to mention ZZP.

www.zzperformance.com has AC delco MAF sensors on sale for 115.00. When my MAF went out, I just bought a new ZZP stage 1 throttle body for 199.99. It came with a new MAF TPS and IAC. Not a bad deal considering the dealership wanted 350.00 for a new MAF.

On the hub bearing question, the wheel speed sensor is part of the hub bearing and cannot be replaced separately. As far as the ABS light, it could be the other hub bearing (although hubs usually cause both the Trac-off and ABs lights to illuminate) or a problem with the ABS system itself. I would have the car scanned with an ABS capable scanner and see what comes up.
I can't readily get to an ABS scanner at the moment Rich, but I am not adverse to changing out my bearing one by one due to the fact that I approaching 120,000 miles and the dealer told me it was a bad sensor when I had brought the car to them about two years ago. I am sure more have gone bad besides the one they indicated 2 years ago. Doesn't that WSS wire have a history of being crimped? I would like to check the volatage accross my current bearings to see if they are bad. Do you happen to know what voltage that they need to be?

That being said take a look at these part(s) links. I agree with you 100% about the WSS being inside the wheel bearing assembly. That's what I always thought. If they can't be changes separately, why are there an option to buy the wheel bearing or just the WSS?

http://www.partsamerica.com/ProductDetail.aspx?MfrCode=BCA&MfrPartNumber=513179&PartType=184&PTSet=A

http://www.partsamerica.com/ProductDetail.aspx?MfrCode=BOR&MfrPartNumber=S8367&PartType=1061&PTSet=A

That being said take a look at these part(s) links. I agree with you 100% about the WSS being inside the wheel bearing assembly. That's what I always thought. If they can't be changes separately, why are there an option to buy the wheel bearing or just the WSS?

http://www.partsamerica.com/ProductDetail.aspx?MfrCode=BCA&MfrPartNumber=513179&PartType=184&PTSet=A

http://www.partsamerica.com/ProductDetail.aspx?MfrCode=BOR&MfrPartNumber=S8367&PartType=1061&PTSet=A


Different part. That is the vehicle speed sensor (VSS) in one of your links. The hub ABS wheel sensors are integrated into the hub and not separately replaceable.

Ahh I see. That's what I thought, but I was confused there for a minute. Does the VSS communicate with the ABS system at all? I am guessing the VSS helps tell your speedometer how fast you are going. Correct? Thanks for clarifing that for me BNaylor.

I have the same problem as Jat, I disconnected the MAF switch and it ran better. Then after like a day I started the car and it wouldn't stay running. I reconnected the MAF and the car ran but I could only get it up to like 30mph. Does this mean the MAF is shot? How hard and expensive is it to replace the part on my own.

My second problem is sometimes when I am going around a corner I hear a very noticable moan and the brakes get kind of jumpy. Before when this problem would happen the ABS light and Trac Off would come on together and the problem would go away. Any idea what this could be?

I have the same problem as Jat, I disconnected the MAF switch and it ran better. Then after like a day I started the car and it wouldn't stay running. I reconnected the MAF and the car ran but I could only get it up to like 30mph. Does this mean the MAF is shot? How hard and expensive is it to replace the part on my own.

My second problem is sometimes when I am going around a corner I hear a very noticable moan and the brakes get kind of jumpy. Before when this problem would happen the ABS light and Trac Off would come on together and the problem would go away. Any idea what this could be?

First off, I changed my MAF and my car runs perfect now. As far as your problem you may have somthing else going on there. My car ran fine with the MAF discoonnected. I may have been getting fewer mpg's but it ran.

As far as your ABS issues: it is either a sensor going bad, or the connecting wires are frayed and periodically loosing connection with the sensor. Mine did the "moan and errrrr" noise before the light stayed on permanently. I needa scanner to figure out which sensor is bad.

Was the catalytic converter and was covered by special warranty by Pontiac. :tongue:

New Check Engine Light. I have code P0141 which the guy at Advance said it's catalytic converter sensor. I recently had the Catalytic converter replaced under the special GM warranty. Was something done wrong or is this a separate issue?

New Check Engine Light. I have code P0141 which the guy at Advance said it's catalytic converter sensor. I recently had the Catalytic converter replaced under the special GM warranty. Was something done wrong or is this a separate issue?

It is a 02 sensor heater circuit malfunction. Referring to the post CAT converter 02 sensor. Check the electrical connector to the post CAT 02 sensor located in the u bend section right after the CAT.

Clevername,

How did you find out it was the catalytic converter, and what did you have to do to get the dealership to fix it under the special warranty? Did you have to get a back pressure test from a shop, and then show the results to the dealer?

The extended catalytic converter warranty only covers 01-02 models for 7 years/120k miles, so many 01 owners may be out of luck by now.

If you think you're eligible, you can just take the car to the dealer and if it fails the backpressure test, you get a new converter no charge. If backpressure is ok, you'll have to pay for the test.

Actually, I called Pontiac customer service and was told that the warranty lasts for 10 years/120K miles (don't know, it may have been extended from the 7 years).

The car has been lacking power under load - going up hills, or trying to accelerate at high speeds. The engine revs, but the car doesn't want to take off. Service Engine light does not come on. I replaced a bad MAF a few months ago (bought it from ZZ) and thought maybe that was it again. Disconnected the MAF, and the car ran better for a few days, but the same problems came back.

I just ran across the issue with the cat converters. I may just have the dealer do a back pressure test like you suggested.

It may be extended to 10 years now. I'd believe them first as things change all the time.