Po102 back agin after MAF replacement - 986 Forum - The Community for Porsche Boxster & Cayman Owners

AKnowles · 09-23-2013, 05:39 PM

Today, I filled up my car at the local Mobil station in the morning. This evening, I started up to drive home, got about half a block, and the CEL came on. Got home and checked it and it is a P0102 Hot Film MAF. I had this error previously so I purchased a new MAF (Bosch) from Pelican Parts. When I replaced the MAF, I did not remove the battery to reset the DME.

Should I clear the codes, reset the DME by pulling the battery, or should I look for other potential causes?

And could it possibly be bad gas or a carbon canister issue (i.e. potential overfill at the pump)?

soucorp · 09-23-2013, 05:56 PM

Quote:

Originally Posted by AKnowles

Today, I filled up my car at the local Mobil station in the morning. This evening, I started up to drive home, got about half a block, and the CEL came on. Got home and checked it and it is a P0102 Hot Film MAF. I had this error previously so I purchased a new MAF (Bosch) from Pelican Parts. When I replaced the MAF, I did not remove the battery to reset the DME.

Should I clear the codes, reset the DME by pulling the battery, or should I look for other potential causes?

And could it possibly be bad gas or a carbon canister issue (i.e. potential overfill at the pump)?

It says it right in the instructions:
* Please remember to reset the ECU after replacing the MAF or the car may continue working as if the old one was still installed. * (by unplugging the battery or reset tool). This is done by a OBDII scanner or unplug the battery, make sure you have the radio code.

Best

Johnny Danger · 09-23-2013, 05:58 PM

That code technically refers to a low voltage reading. However, in most cases, it's an indication that the sensor itself has failed. In more complicated situations, it can be an indication that voltage between the DME and the sensor is being interrupted - i.e. a bad wire(s). Try resetting the CEL by disengaging the negative battery cable for a few minutes. Some have suggested the following steps before starting:
- turn the ignition to "full accessory" for about a minute
- remove the key from the ignition for few seconds
- then start the vehicle

I can't vouch for that part, other than to say that I've followed those steps in the past.

AKnowles · 09-23-2013, 06:03 PM

I didn't have any instructions with my MAF. It was just wrapped in paper. But I did use my PST2 to clear the codes. I thought that reset would be enough. It has been error free for over a month. I'll try the JD special car handshake routine above and see if that resolves the issue.

Thanks for the feedback.

The Radium King · 09-23-2013, 06:07 PM

no funny oiled air filter that might be fouling it?

AKnowles · 09-23-2013, 06:09 PM

No. I used a paper filter. Replaced it about 7K back.

AKnowles · 09-23-2013, 07:21 PM

Well the car and I exchanged the secret JD handshake and no CEL on startup. Thanks JD. Will see what happens on my way to work tomorrow.

I really hope it is an easy fix as I just scheduled my car to get the windshield replaced. Mostly because my visor retention nuts have broken and to replace the plate that holds the nuts requires removing the window. The other reason was minor glass pitting from 15 years of use.

And FWIW, I do know I could have put in a nutsert, but decided I just didn't want to drill in to the cowl area. Just didn't seem right to me.

AKnowles · 09-24-2013, 04:45 PM

Well, on the way to work with an ambient temperature of about 70 life was good since the CEL did not reappear. On the way home, ambient temperature of about 100, I drove about 300 feet on a gravel parking lot and the CEL came back.

I checked the MAF hot film actual value and at idle it is 1.01. At 3K it is also 1.01. I thought it was supposed to be higher than that from what I'd researched. In any case, I'll buy some MAF cleaner this weekend, pull my air filter and check for debris, leaks, etc. and see if that clears the code. If not, I'll have a chat with Pelican parts sicne the MAF is barely over 5 weeks old. Maybe they'll have some useful information.

paulv · 09-25-2013, 03:43 AM

As JD mentioned earlier, there could be wiring issues -- an intermittent open circuit or short to ground. Also, according to wiring diagrams, there's an ECM relay that is powered from pin 27 of the DME to pin 2 of the relay; pin 5 of the relay goes to pin 2 of the MAF sensor.

Regards,
paul...

Johnny Danger · 09-25-2013, 04:53 AM

Quote:

Originally Posted by AKnowles

Well, on the way to work with an ambient temperature of about 70 life was good since the CEL did not reappear. On the way home, ambient temperature of about 100, I drove about 300 feet on a gravel parking lot and the CEL came back.

I checked the MAF hot film actual value and at idle it is 1.01. At 3K it is also 1.01. I thought it was supposed to be higher than that from what I'd researched. In any case, I'll buy some MAF cleaner this weekend, pull my air filter and check for debris, leaks, etc. and see if that clears the code. If not, I'll have a chat with Pelican parts sicne the MAF is barely over 5 weeks old. Maybe they'll have some useful information.

There's a real possibility that the sensor itself is defective. There have been several articles written over the years that have outlined quality control and reliability issues with Bosch - depending on which of their numerous facilities the part was manufactured in. After all, a MAF sensor is nothing more than a simple piece of plastic with a glorified paperclip and a small strip of film. It doesn't take much to make one, nor does it take much to make it wrong. See if they will exchange it for another one.

AKnowles · 09-25-2013, 10:32 AM

I have a query in with Pelican Parts to check on it now. FWIW, the ride in to work again was just fine with no CEL. I wonder what the evening ride home will be like.

AKnowles · 09-28-2013, 06:54 PM

Well, looks like my MAF is going back to Pelican Parts for an exchange. Spent quite a bit of time with it this weekend and no joy with any of it. There is no oil in the intake (bone dry and clean actually), no dirt, and even a squirt of MAF cleaner didn't help. So, now I'm limping along with no MAF connected since I put my old MAF back in place (after a cleaning too) and had my car revert to the no start when hot scenario. Ah well, at least this time I knew the cause so just popped the engine access in the parking lot and disconnected the MAF.

AKnowles · 10-03-2013, 12:05 PM

Just a follow up: I bought a replacement MAF via Pelican Parts while my previous MAF went back for a RMA/Refund. The new MAF is working fine and I have not experienced the P0102 error. Plus this MAF is registering variable voltage unlike it's predecessors.

Kudos to Pelican for their customer service and standing behind their products.

Johnny Danger · 10-03-2013, 06:03 PM

Quote:

Originally Posted by AKnowles

Just a follow up: I bought a replacement MAF via Pelican Parts while my previous MAF went back for a RMA/Refund. The new MAF is working fine and I have not experienced the P0102 error. Plus this MAF is registering variable voltage unlike it's predecessors.

Kudos to Pelican for their customer service and standing behind their products.

Good news. I suspected the sensor might be NG.