P0102 Code

[bobt]

Just returned to AZ from two months in PA visiting parents and family. Truck sat in PA for 7 weeks with one start up about 1st of July. On morning of 20 July started truck to leave and had engine light and reduced power advisory. First mile and half is downhill to main road, so decided to go and head toward dealer (25 miles away) in case didn't clear. At bottom of hill, turned onto main road with slight upgrade. Found out reduced power really means no power. Turned around and barely made it back up hill to parents' place. Got out code reader for first time (this is not the time to be learning how to use code reader) and got P0102 which it said was "mass or volume air flow A circuit low". After using reader to clear codes, it finally went away, I thought. Turned everything around and hooked up Jeep Wrangler I was towing and headed out. Got about 5 miles and code hit again. Headed back to parent's place up the hill and just before I got to the top, the code cleared itself and the power came fully back. Let the truck idle a while at house, then drove it down hill and back up with no problems. Turned everything around again and headed out again with fingers crossed. Code never recurred. The humidity had been high for several days prior and it had rained heavily the two days prior to us leaving. My thinking is that the humidity from the rain had somehow affected a connection to the MAF sensor or the sensor itself and the heat from the engine running for a while finally dried out the problem area. Anyone have a better understanding of what might have caused this problem? Also, I would like to check out the sensor and the connections. Will someone explain to me where this sensor is located on my '09 Dmax? Any and all advice will be much appreciated.
Bob

[Kennedy]

The MAF sensor is in the air box. This could also be interrelated with the Boost sensor. If it was cold out I'd say it could have been frosting/icing in the port of the boost sensor, but that is unlikely.

Having a code reader and the knowledge/ability to use it = priceslless.

[bobt]

Thanks John for the response and answers. It was too warm that morning to be an icing or frosting issue.

You are right about the code reader and I intend to be more knowledgeable with regard to using it before the next time.

I also got a P0113, Intake Air Temperature Sensor 1 Circuit High, code one time during my attempts to clear the P0102 code. It cleared immediately and never recurred so I ignored it as being related to the P0102 and not the major problem.
Bob

[DmaxMaverick]

Thanks John for the response and answers. It was too warm that morning to be an icing or frosting issue.

You are right about the code reader and I intend to be more knowledgeable with regard to using it before the next time.

I also got a P0113, Intake Air Temperature Sensor 1 Circuit High, code one time during my attempts to clear the P0102 code. It cleared immediately and never recurred so I ignored it as being related to the P0102 and not the major problem.
Bob

The IAT sensor is part of the MAF sensor. A poor/intermittent MAF sensor connection, or a dirty MAF element (little wires inside the "horn") can cause the issue. If a disconnect, clean (the elements and connector contacts), reconnect, and code clear cures it, even for a while, it could just be a poor connector issue. This is most often the problem on earlier models.

[rapidoxidationman]

So did you take apart the air box and check for obstructions (spider webs)?

[bobt]

Thanks for all the inputs. No, I haven't checked the air box out yet. After getting it going on the 20th, didn't have any further problems on the 2100 mile trip back to AZ not the couple times driven in Tucson since. Will probably take a look at it this weekend to see if there is anything obvious. Also will check out the MAF sensor while in there.
Bob

[More Power]

I didn't see where you mentioned what type of air filter element you might be using. Some of the aftermarket oiled gauze/foam types can produce a problem with the MAF sensor (cases are rare and an oiled gauze element is usually not a problem). I've been running an oiled foam air filter element for several years without a problem.

Your local NAPA store should have a spray cleaner identified/labeled as a MAF sensor cleaner. You can can place a clean rag beneath the sensor in the ducting between the air filter box and the turbo, then carefully spray the sensor to clean it. Be sure to remove the rag before starting the engine.... ;)

All of the electrical connectors under the hood are the sealed/weathertight variety, and should be resistance to water entry, though a powerwasher could force water into the connector if sprayed directly onto it.

Jim

[bobt]

I'm running the original air filter. I have only 20,000 miles on the truck. I haven't looked at the filter yet, but the filter condition indicator is showing good. I'll pick up some of that spray cleaner so I can clean the MAF sensor.

Bob

[DmaxMaverick]

There's no normal reason you should have a dirty MAF sensor. It's on the "clean" side of the filter. If a critter (rodent,etc.) got in there and chewed a hole in the filter, the Filterminder would still indicate good. It only indicates restriction. A dirty or partially blocked filter can alter the airflow enough to cause MAF errors, even if the filter is not dirty enough to trip the Filterminder. It's hard to say, with so few miles in nearly 4 years. If you haven't replaced the filter, do so. Also, it doesn't hurt to shoot some cleaner in the MAF. If you prefer to remove it for cleaning, just remove the screws and wiggle it out. It's sealed in with an O-ring. I also suggest cleaning of the connector contacts, and use of dielectric grease on the seals (O-ring and connector gasket), and connector pins. Also check the intake plumbing for leaks or loose connections. A MAF error code commonly means the actual input value is not what's expected, and a leak can cause that.

[bobt]

Well, I opened up the air box today. Everything was spiffy clean: could practically eat out of it. Filter looks good. Intake side shows a little dust/dirt. Outlet side looks brand new. MAF connection is clean with no moisture/corrosion indications whatsoever. I'm thinking my problem was a transient moisture problem on the MAF sensor. The truck had been sitting for over three weeks. It had been raining the day before and it was very humid that morning. I started the truck and ran it for about one minute before shutting it down for about a half hour while I hooked up the Jeep and got ready to go. I think condensation formed on the sensor and that is what caused the code which went away once the moisture on the sensor evaporated from the truck running for awhile. Thanks to all for your input and advice.
Bob