First it's a ABS/PSM warning, then replace harness, now it's the CEL! WTF!!
 

Researched here recently on the common ABS/PSM warning and decided to go first with replacing the wiring harness. Now, today I am on the freeway and cruising with no error codes after 250 miles of driving since the new harness was installed Friday. I come up to a Roush supercharged late model Mustang and get him to have a little fun. From about 75mph we both punch it, I am in 4th and shift into 5th and at about 4500 in 5th (yes, after I pulled on him) the car acts like it just shut off fuel, and then a couple seconds later everything is restored to normal. Car is still driving fine and cruising and no error codes... yet. About 5-10 seconds later the ABS/PSM warning comes back on. Hmmm.... so I cruise another 10 miles to my office and after I get off the freeway I test the car and do a little WOT run in 1st and 2nd and everything seems normal. I turn off the car and work for a few hours. Then I get back in the car to leave later and after about a 1/2 mile of normal low speed driving in town the Check Engine light comes on. WTF! ABS/PSM and CEL are all now on! The car is still running normal and I don't feel anything different than before.

My first thought is the MAF. Thoughts? Did that harness even have anything to do with my issues? Was that an unnecessary replacement? Should I have replaced the MAF instead? Hell I dunno what the hell is going on here..... I am lost. SOS.

HArness?? first time I ever heard of a problemn like that.... usually its the maf...
u running a V flow? did the temps drop recently?
disconnect the maf by unplugging the harness to it.... start the car... warm it up.... the cels will come on.... dont worry..... then get on it same way as before.... if it doesnt sputter then then its ur maf.... if it does then its a massive intake leak.... also, can u check ur afrs? usually when MAFS go bad the afrs on boost go thru the roof/.....

Well several people said they have same codes as me (right front ABS sensor) and then replacing that harness did the trick. So we tried that first.

Yes, I have the V-flow, and I know the previous owner blew a couple MAFs he said before.

I just drove it home 40 miles and all gauges reading normal.

I am pretty new to these cars so where is the best place to find instructions/pics of how to unplug and replace the MAF?

I do not know how nor do I think I have the capability to check AFRs.

thanks Mark

maf, lose the v-flow....

well there is ur answer... but I have seen it work with other software....

95% of the time its the MAF

+1, Statman knows, Markski too.

So... you guys think it might be the MAF? LOL

Okay, thanks everyone for the quick replies. I think this is something even I can attempt to do myself with my little to zero mechanical skills. Will be good for me. Plus the MAF is pretty cheap too. I will eventually replace this intake and maybe the MAF when I go with a turbo upgrade which I am still trying to decide on. I guess for now I just wanna band aid it.

thanks

It is a very simple process to replace the MAF. Trust me, if I could do it anybody can. It takes 5 minutes top.

If I just replace the MAF do I still need to have the error codes deleted? They won't just go away on their own will they (assuming I fixed the issue) ?

They won't completely go away until you get rid of the V-flow. That is what is blowing your MAF.

A failing or failed PSM control unit can also cause intermittent codes or continuous ones relating to ABS/PSM, even after you clear them. If MAF sensor isn't the problem have someone check it.

Disconnect the battery for 5 minutes will clear the codes (don't forget your radio code). The MAF is easy to replace (not sure how cheap they are these days), but it will blow again if you boost with your current set-up.

Before replacing the harness, did you get the CEL with the ABS/PSM lights? From what I read from other past threads, it seems that the MAF problem has ABS/PSM and CEL lights. From the few of us that replied to your last thread, we didn't get the CEL, just ABS/PSM, which we had actual ABS/PSM issue, not the MAF. Good luck with this, I know it sucks.

For those of you that had MAF issues, and you got the ABS/PSM lights,
Did the ABS Failure and PSM Failure, take car into nearest dealer immediately messages appear on display?

Or did just the little round ABS and PSM light illuminate?

Its' the MAF almost for sure.

How much boost are you running? Overboosting will give you that rev limiter feel.

Also make sure you have the V-Flow upgrade installed. Basically, it's just an aluminum housing that retrofits the waffle from the stock airbox into the V'Flow. If you can see a waffle in the air path into the engine (right behind the filter) you're good.