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I have a 1999, C4, manual trans. Lately the car has been surging when cold. You can hear the engine surge (minor hunting) when its idling (maybe 50-100 rpm's.) The car tends to bog after taking off and then the surging (increase and decrease in engine speed without moving the accelerator) becomes more noticeable at speed. The ABS and PSM warning lights usually come on after that, usually within 3 minutes. My independent pulled codes P0102 and 5525. I replaced the MAF (plus air filter and cleaned the airbox) with a new unit a few days ago with no change. After the car warms up 5-10 minutes, the surging stops and the car runs perfectly. The warning lights go away after re-start and symptoms stay away as long as the engine is not cold. Do I need to reset the ECU at this point (by removing power) or will the symptoms gradually go away (if it was the MAF) or do I have other issues.

Any help is much appreciated.

Jerry

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  • Admin

:welcome:

P0102 Mass Air Flow Sensor – Below Limit

– Open circuit

– Short circuit to ground

– Mass air flow sensor

ABS Fault code 5525

Incorrect data exchange from DME

- clear and see if it returns

For the surge problems try cleaning the throttle body and MAF (use only approved MAF cleaner). Covered here many times before.

If the problem persists then you likely have a bad MAF.

For the ABS problem - check your brake lights - do they come on? if not, then you have a bad brake light switch.

If they do come on then I would reset the fault and see if it comes back.

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:welcome:

P0102 Mass Air Flow Sensor – Below Limit

– Open circuit

– Short circuit to ground

– Mass air flow sensor

ABS Fault code 5525

Incorrect data exchange from DME

- clear and see if it returns

For the surge problems try cleaning the throttle body and MAF (use only approved MAF cleaner). Covered here many times before.

If the problem persists then you likely have a bad MAF.

For the ABS problem - check your brake lights - do they come on? if not, then you have a bad brake light switch.

If they do come on then I would reset the fault and see if it comes back.

Ok, since I've already replaced the MAF, I'll clean the throttle body and see what that does. The brake lights work fine and from what I've read the ABS/PSM warning lights are somehow connected to the MAF issue. I had also read here that the MAF had little to do with idle/low rpm issues as it only came into play at higher rpm's.

Thanks, Jerry

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  • Admin

If you already replaced the MAF - then it is not connected (that is what the fault says). Check the cable and connector.

The MAF would not cause surging at idle - you can disconnect it at idle and the idle will not change.

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I have not had codes read since replacing the MAF. I simply replaced it after my tech said codes P0102 and 5525. I was hoping that the surge and hesitation would go away when the engine was cold (after replacing MAF), it did not. I just cleaned the throttle plate area and will now have to see how it behaves this evening or tomorrow morning. I thought that maybe I'd need to remove the battery power after replacing MAF (to clear ECU), I thought that I'd read that here somewhere but wasn't sure. If the surging when cold only is not the MAF then it must be something else, we'll see if the throttle body cleaning helped. I did get some residue but nothing compared to my SVO mustang but that's a different set-up with turbo charging and all.

Thanks for all the help! Will let you know what happens when the engine's cold again.

Jerry

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I have not had codes read since replacing the MAF. I simply replaced it after my tech said codes P0102 and 5525. I was hoping that the surge and hesitation would go away when the engine was cold (after replacing MAF), it did not. I just cleaned the throttle plate area and will now have to see how it behaves this evening or tomorrow morning. I thought that maybe I'd need to remove the battery power after replacing MAF (to clear ECU), I thought that I'd read that here somewhere but wasn't sure. If the surging when cold only is not the MAF then it must be something else, we'll see if the throttle body cleaning helped. I did get some residue but nothing compared to my SVO mustang but that's a different set-up with turbo charging and all.

Thanks for all the help! Will let you know what happens when the engine's cold again.

Jerry

So if I understand correctly....you replaced the MAF, but did not clear the codes. You should clear the codes...if you do this via a battery reset, you will have to let the ECU re-learn. I would clear them, run the car and then read the codes again.

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Clean the idle valve as well. It is easy and you should find a thread if you do search.

There is no idle valve on a MY99 C4 - all C4's had egas.

Thanks Loren, I didn't know that about the C4's

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I have not had codes read since replacing the MAF. I simply replaced it after my tech said codes P0102 and 5525. I was hoping that the surge and hesitation would go away when the engine was cold (after replacing MAF), it did not. I just cleaned the throttle plate area and will now have to see how it behaves this evening or tomorrow morning. I thought that maybe I'd need to remove the battery power after replacing MAF (to clear ECU), I thought that I'd read that here somewhere but wasn't sure. If the surging when cold only is not the MAF then it must be something else, we'll see if the throttle body cleaning helped. I did get some residue but nothing compared to my SVO mustang but that's a different set-up with turbo charging and all.

Thanks for all the help! Will let you know what happens when the engine's cold again.

Jerry

So if I understand correctly....you replaced the MAF, but did not clear the codes. You should clear the codes...if you do this via a battery reset, you will have to let the ECU re-learn. I would clear them, run the car and then read the codes again.

I don't have any way of reading codes yet, need to invest in an OBDII reader. Are the relatively cheap ones worth buying? Amazon sent me an offer for an Equus 3030 Innova for $59.99 today. I did have the codes cleared by a shop before installing the new MAF and I did not drive it again until the MAF was installed. First time I drove it (engine cold) the ABS/PSM warning lights came on as I described in the first post. The car is due for its 75K service in about 500 miles so I'll have the dealership check the codes and see what they say if the cold driving symptoms remain after this throttle body cleaning.

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I don't have any way of reading codes yet, need to invest in an OBDII reader. Are the relatively cheap ones worth buying? Amazon sent me an offer for an Equus 3030 Innova for $59.99 today. I did have the codes cleared by a shop before installing the new MAF and I did not drive it again until the MAF was installed. First time I drove it (engine cold) the ABS/PSM warning lights came on as I described in the first post. The car is due for its 75K service in about 500 miles so I'll have the dealership check the codes and see what they say if the cold driving symptoms remain after this throttle body cleaning.

Well I suggest the durametric...more $, but way more capable. Without a real code reader you are at the mercy of the shop. Apparently the MAF may not have been bad (hope you kept the old one) or at least was not the only issue. You sure you got the complete set of codes (did you see them?) You could have already paid for the durametric...GL.

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Well I started the car this morning and the idle seemed to be better but still hunting a bit after the air pump turned off and the idle dropped. I would say the hunting is minimal, less than before. The bad news is that it was 70 degrees here this morning and perhaps that's why it ran pretty good. It was only slightly sluggish taking off and the ABS/PSM lights did not come on. Perhaps the throttle body cleaning did the trick, will have to wait for a cooler morning to be sure. Perhaps the ECU still has some learning to do with the new MAF? I will have the dealer check codes and tell them about the surging when it goes in for its 75K maintenance. Thanks for all your help, this was my first issue so I really appreciate it.

Jerry

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  • 4 months later...

I thought that I'd end this thread with the answer to what finally solved my problems. Perhaps this will help people with similar issues. The electronics in the Throttle Body turned out to be the culprit. I had changed out the MAF with no change and the dealer remapped the ECU with no change. The throttle body was cleaned thoroughly and that also rendered no change. I took it in to my independent who drove it from cold one morning and he noticed a lot of noise (loud clicking sounds) coming from the throttle body. The codes retrieved at that time were P0102, P1503 and P1506. P1503 and P1506 were not present when this issue began. I ordered a new throttle body upon the recommendation of my independent, it took about 15 minutes to install and voila. No more surging, no hesitating, no ABS/PSM lights etc. Throttle response also seems much smoother now. Hope this helps someone and thanks for all the input.

Jerry

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