Dtc P0103, Maf Input Too High.......

ZenProtege

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Mazda Protege Titanium 03.5
Dtc P0103, Maf Input Too High.......Problem Solved

Problem solved! I explain more on the cause a few post down

My car has been acting funny lately under full boost from 4k and up. It stumbles and misfires irradically as I pull to redline. The problem is best decribed as being very similar to FC(almost like several mini fuel cuts instead of one hard one), and it is usually followed by intermittent normal fuel cuts 50% of the time after the stumbling/choking out hesitation begins. When the problem occurs, my car becomes extremely sluggish and acceleration is extremely irradict. Up until yesterday, I had never gotten a CEL to help pinpoint the problem despite the fact it's been happening for 2-3 months now. I had a suspicion it was a problem with the MAF or somthing in the secondary ignition circuit. After reading more info , I've found that DTC can be triggered as a result of several things. Has anybody else gotten this DTC, and if so, what was your problem? I'm not easily inclined to buy a new maf and bolt it up there too see if it solves the problem, so I have to make sure nothing else is causing the problem before I replace the unit.

What I've checked out/cleaned so far:

Coils are fine
Plugs are fine
Wires are fine
Maf and IAT have been cleaned with electric cleaner
EGR has been removed and cleaned
TB has been cleaned
Car has relatively new copper plugs as well
All couplings have been checked and re-checked for a good seal .
New Airfilter 4 months ago
Seafoamed every month
Reset PCM
Retightened all connections in aftermarket exhaust

Car pulls 22-24 " of HG at idle, so engine vac is good

Boost holds steady. (I'm at stock boost)

my MAF IS RELOCATED!

MODS listed below

I think my problem is being caused by something other than the MAF....
Does anybody know of a definate way to check the MAF?
 
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yea, I mentioned that I had a CEL... that's how I got the DTC p0103. It turned itself off after a few drive cycles. I wasn't too surprised that happened.....That particular code can result from many different things going wrong. I've been trying to diagnose this problem long before having the CEL. All the code did for me was reaffirm what I thought the problem may be caused by

I have a suspicion that maybe a vac line is leaking only under full boost, or that a damaged plug wire is only giving trouble under a full load. Since I don't know how to properly check the short plugs that attach directly to the coils w/ the sping in them,there is still a very small chance this is somehow spark related in my mind. I'm also curios if there is a fault in the wiring for the maf, maybe a poor ground or connector in the harness is making bad contact and throwing it off. From my own experience, either a maf is functional or broken. I've never had to replace a worn out maf that still worked.
 
another maf. read the shop manual, it will tell you what steps to take to trouble shoot.
 
i AM HAVING THE EXACT SAME PROBLEM HOLY CRAP. i JUST POSTED THIS NOT 2 WEEKS AGO. I will be following this thread. I have the relocated maf also. Mine only does it when its around 80 degrees or so. Not when its cold. I have the relocated maf also. I think there is a way to get rid of the maf all together. I don't remember what it was but it was on this forum.
 
Blitzd said:
I think there is a way to get rid of the maf all together. I don't remember what it was but it was on this forum.

Standalone EMS?
 
I don't have a shop manual. If anybody can scan a copy of that guide or has a link to that it would be very much appreciated!
 
The MAF too high code could be because you are hitting fuel cut too much. Fuel cut is when the MAF sends the ECU a certain voltage, I think it's around 4.7-5v depending on the load and all. So maybe with it being on the pressure side, it's seeing that voltage more often and the ECU is like WTF! How much boost? If the boost was too high, then that would trigger too much MAF voltage more often, especially since it's on the pressure side. I could be all wrong on this as well, I'm no MSP expert.

The manual is at http://protege5.ugly.net/
 
bigg tim is exactly correct...im betting its a combo of around 10psi boost and being on the pressure side...
 
PCM monitors input voltage from MAF sensor after ignition key is turned on. If input voltage at PCM terminal 88 is above 4.90 V, PCM determines that MAF circuit has a malfunction.

Possible cause: MAF sensor malfunction, Connect or terminal malfunction, or short to power circuit in wiring between MAF sensor terminal C and PCM terminal 88.

Straight out of the manual. There's a troubleshooting process but none of them you'd be able to do, unless you know what to do with freeze frame data and can acess the MAF pid. It says check connections, at the maf sensor, like check for bent terminal on the maf sensor connector, or make sure it is connected to the PCM properly, and inspect the maf signal circuit for short to power circuit. GL
 
I have the same problem. It actually just happened to me yesterday. It started when I was getting on the highway and then it stumbled and the CEL came on. This happens to me when it rains excessively and I think moisture creates the issue. All I do to cure this problem for me is disconnect the battery then reconnect and it should be good to go. I have a FMIC with the MAF relocated. This only happens to me when it poors for days and again I do beleive this is from moisture.
 
smo0f said:
PCM monitors input voltage from MAF sensor after ignition key is turned on. If input voltage at PCM terminal 88 is above 4.90 V, PCM determines that MAF circuit has a malfunction.

Possible cause: MAF sensor malfunction, Connect or terminal malfunction, or short to power circuit in wiring between MAF sensor terminal C and PCM terminal 88.

Straight out of the manual. There's a troubleshooting process but none of them you'd be able to do, unless you know what to do with freeze frame data and can acess the MAF pid. It says check connections, at the maf sensor, like check for bent terminal on the maf sensor connector, or make sure it is connected to the PCM properly, and inspect the maf signal circuit for short to power circuit. GL


I have access to a scanner and have already made a movie. My maf kept voltage as it should...but, it could have spiked up between one of the RPM increments it wasn't logging on. The scanner for some reason is having trouble exporting a data to the computer, so that makes it tricky to review as well. I'm going to check the signal wire at the PCM next...thanks for the terminal info smoof.
I'm working with a good friend and seasoned mechanic on the problem now. I have access to a host of different tools, and he would be able to clarify any tricky diagnostic procedures like you mentioned. He has 15 years experience as a master tech for ford, and another 10 years of building tranny's and another 13 years as a shop owner as well as being ASE mastercertified all fields with some kind of speciatly certification in electrical. It's nice to have him on my side, but it's kinda irritating bc whether or not he knows whats wrong with my car, he'll make sure I figure it out before giving me any hints so I'll learn on my own.
I made a short movie of my car stumbling...I hope that will help you see the problem a little better and further clarify what I'm describing....I'm having trouble putting it up here bc of it's size...I need to find somewhere that will host it...
 
The data won't export from the scanner to the computer for some reason :( ...I'm waiting on google to approve my video that a shows a few good clips of what I'm describing. I'll have that posted as soon as it goes through. It'll also show how an apexi n1 exhaust and turbo specialties BOV sound during 3rd and 4th gear pulls
 
Can you just read off the scanner things like CTS, TPS, MAFv, long and short term fuel trims, vehicle speed and calculated load?
 
THANK GOD!

I have finally solved this unbelievably irrating problem. My MAF wasn't the problem. Well, no malfuncioning sensors or engine parts were causing this. Turns out my boost guage having a short in it was the culprit. Upon puchasing a used dual guage pod with boost and volts guages from a forum member, I was always tripped out that the LED's on the guages didn't work even though they were properly connected. Turns out one of the guages had a short in it that was unfortunately causing power to flow into the ground circuit. As I was testing the MAF's circuit, I noticed a .3-.4 volt reading on it's ground wire upon doing a voltage drop test. After a good bit of trouble shooting and looking over wiring schematics, I found the MAF was powered from the main engine relay, which was powered from the ignition circuit, which was tapped into to the power wire that fed my TT, and my guages were fed fed off the TT's power wire. So through that grape vine of wiring, the boost guage managed to **** with the output of my MAF for months by grounding out current from that circuit. I realized the problem all at once when I saw how the circuits were tied together. I have had 2 other DTC's that were unexplainable up until now as well, I've come to find they were also powered on by the main relay. It was amazing, As soon as I 'took care of the guages' (lol) I went for a drive and hit redline for the first time since this thread....ohhhh...it felt good. I never would have guessed those seemingly innocent guages were the problem all along. My biggest mistake on troubleshooting this issue was not checking the wiring close enough. I made the assumption that since it was a new car, drivability issues would be caused by malfunctioning parts (ie, bad maf), instead of basic faults like a bad ground circuit.
 
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