Will a MAF sensor failure disable a vehicle? (FORD, sighhh)

motionclone

Well-known member
Lifetime Member

Equipment
L345DT with Lp mower, forks and grapple thumb, Bobcat 337 Midi Ex
May 4, 2018
1,398
992
113
Maine
2020 F350 with 7.3 gas, 25k miles. Broke down on side of the road and had to be towed to stealership. Loss of all power like the fuel or spark got shut off. Engine dead, would crank but not restart.
Service said it was a dirty MAF sensor, replaced and all is good for now.

BUT just 20 miles prior to this supposed MAF failure, the truck was at same shop to have the AC compressor replaced because they say it failed, no cold air.

So i have some suspicions that something they did accidently while replacing the ac compressor , caused some other failure that led to me being broken on side of the road.

I just cant believe that only 1 day and 20 miles out of the shop i have an unrelated failure that leads to being stranded. and a dirty MAF shutting the engine down while driving? And no engine light prior either.

Apparently it was the same tech that did both the ac compressor and the MAF sensor.

And this tech is sloppy. He left his scan tool on the front passenger seat (so i returned to the service guy) and the day after work was done i found the cardboard box that a new MAF sensor came in under the hood laying on the engine..lol
 

Daren Todd

Well-known member
Lifetime Member

Equipment
Massey Ferguson 1825E, Kubota Z121S, Box blade, Rotary Cutter
May 18, 2014
9,116
4,635
113
Vilonia, Arkansas
I will say this. If they didn't replace the condenser when they replaced your ac compressor, then your gonna probably experience another compressor failure within the next year or so.

I had a similar issue with my F150. AC went out at low miles. Dealership replaced the AC compressor only. Within 2 years the AC was out again on the truck.
 

johnjk

Well-known member
Lifetime Member

Equipment
B3200 w/loader, Woods RC5 brush hog, 4' box blade, tooth bar, B1700 MMM,
Apr 13, 2017
1,291
904
113
West Mansfield, OH
MAF, that is inline from the air filter to the throttle body correct? I would validate you have your air filter in place if they were that sloppy and it is clean. I usually clean my MAF with sensor cleaner every six months And no problems. Not sure how it could fail during AC service but then again they could have cracked the connector if they didn’t remove the cable had they needed to remove the intake hose. This may have caused the cable to fall off and you Joe have a “failed “ sensor which is on your dime, not a broken one on theirs. Maybe time for a new shop? On the question of disabling a vehicle, yes I’ve had a bad one cause a car not to run. It uses that data to adjust the air fuel mix in so if it is dead, todays cars can’t figure out what to do.
 

fried1765

Well-known member

Equipment
Kubota L48 TLB, Ford 1920 FEL, Ford 8N, SCAG Liberty Z, Gravely Pro.
Nov 14, 2019
6,720
4,247
113
Eastham, Ma
2020 F350 with 7.3 gas, 25k miles. Broke down on side of the road and had to be towed to stealership. Loss of all power like the fuel or spark got shut off. Engine dead, would crank but not restart.
Service said it was a dirty MAF sensor, replaced and all is good for now.

BUT just 20 miles prior to this supposed MAF failure, the truck was at same shop to have the AC compressor replaced because they say it failed, no cold air.

So i have some suspicions that something they did accidently while replacing the ac compressor , caused some other failure that led to me being broken on side of the road.

I just cant believe that only 1 day and 20 miles out of the shop i have an unrelated failure that leads to being stranded. and a dirty MAF shutting the engine down while driving? And no engine light prior either.

Apparently it was the same tech that did both the ac compressor and the MAF sensor.

And this tech is sloppy. He left his scan tool on the front passenger seat (so i returned to the service guy) and the day after work was done i found the cardboard box that a new MAF sensor came in under the hood laying on the engine..lol
From my 39 total years of flying:
When/if we (pilots) found any tool left behind on an aircraft by a mechanic, we KEPT the tool.
It was simply a safety issue for us.
Mechanics needed to learn that leaving their tools around indiscriminately, could cause fatalities.

I would have made that scan tool on the front seat, .....disappear,......permanently!
 

Fordtech86

Well-known member
Lifetime Member

Equipment
L3200
Aug 7, 2018
4,833
5,671
113
Pineville,LA
Yes the MAF can shut it down like you described. What typically happens is there is debris (bugs, dirt,etc) that is around the air filter housing lid, the lid and tube to intake was probably removed to get access to remove the belt. If that stuff isn’t cleaned off (ideally before even removing it), when it goes back together it gets moved around then can get pulled into the MAF sensor. Warranty doesn’t pay for removing bugs from sensor, likely why it was replaced 😉
 
  • Like
Reactions: 1 user

The Evil Twin

Well-known member

Equipment
L2501, LA526,
Jul 19, 2022
2,402
2,323
113
Virginia
While it will "eventually" cause a no-start or stall situation, a dirty MAF usually shows signs first. Rough idle or surging is common. Followed by a MIL and code. Then, you run into a no start. They don't just all of a sudden get dirty and fail. If they do, then your complete intake plumbing is dusted and needs to be removed and cleaned because you had a major air leak or ran without a filter.
Much like @Fordtech86 said- probably something they did while doing the AC. My guess: All too often a tech will stuff a rag in the intake after removing part of it to do work. Great idea to prevent things from falling in. Only you have to remember to retrieve them when putting things back together.
It will be worth your time to pull the intake apart to make sure the inside is not dusted.
 

BruceP

Well-known member

Equipment
G5200H
Aug 7, 2016
837
355
63
Richmond, Vermont, USA
2020 F350 with 7.3 gas, 25k miles. Broke down on side of the road and had to be towed to stealership. Loss of all power like the fuel or spark got shut off. Engine dead, would crank but not restart.
Service said it was a dirty MAF sensor, replaced and all is good for now.

BUT just 20 miles prior to this supposed MAF failure, the truck was at same shop to have the AC compressor replaced because they say it failed, no cold air.

So i have some suspicions that something they did accidently while replacing the ac compressor , caused some other failure that led to me being broken on side of the road.

I just cant believe that only 1 day and 20 miles out of the shop i have an unrelated failure that leads to being stranded. and a dirty MAF shutting the engine down while driving? And no engine light prior either.

Apparently it was the same tech that did both the ac compressor and the MAF sensor.

And this tech is sloppy. He left his scan tool on the front passenger seat (so i returned to the service guy) and the day after work was done i found the cardboard box that a new MAF sensor came in under the hood laying on the engine..lol
All cars have "redundant" systems to reduce 'single point of failure'. The MAF sensor is one of those.

Infact, the electrical plug to the MAF can be TOTALLY DISCONNECTED and the engine will start and run (in limp mode) so vehicle can be driven.

A dirty MAF can be cleaned and put back into service for many more years of service. There is no need to replace it.

As an outside-observer reading your story, I would suggest this 'dealership' is incompetent (guessing at what is wrong) or perhaps underhanded (trying to make more $$ )

Over the years, I have had PERSONAL experience not unlike yours with more than one 'dealership'.
I ended up locating a TRUSTED LOCAL SHOP who I have stuck with for 10+ years.
 

motionclone

Well-known member
Lifetime Member

Equipment
L345DT with Lp mower, forks and grapple thumb, Bobcat 337 Midi Ex
May 4, 2018
1,398
992
113
Maine
Thanks for all the input!

The AC is actually starting to act up again. Blows barely cold at idle. Shutting it off then back on makes it blow cold again. Its done this twice now. And the compressor repair was about 15 days ago..lol

All this work is being done at a ford dealership and under warranty.

I asked my service writer if the same tech did the compressor and the maf (and left stuff in my truck and under the hood) and he confirmed same tech so i told him to not let that guy near my truck again.

About the MAF, the writer said it was dirty and thats why it failed likely because i didnt change my filter enough. Except ive changed my filter at every other oil change. The theory that some debris entered when the tech did the compressor service seems very likely now.


Also an interesting note. When i broke down the truck was going 44mph on a maine winding back road and had no symtoms just died like key or fuel was shut off.

I had to be towed off the road, then a flatbed came and got me and took the truck to the ford dealership.

The service writer wrote that the truck came in with a service engine light as the complaint even though i made it clear that it died in the middle of the road and had to be towed in.

Probably time for another dealership but im guessing ill find more of the same.
 

Fordtech86

Well-known member
Lifetime Member

Equipment
L3200
Aug 7, 2018
4,833
5,671
113
Pineville,LA
Thanks for all the input!

The AC is actually starting to act up again. Blows barely cold at idle. Shutting it off then back on makes it blow cold again. Its done this twice now. And the compressor repair was about 15 days ago..lol

All this work is being done at a ford dealership and under warranty.

I asked my service writer if the same tech did the compressor and the maf (and left stuff in my truck and under the hood) and he confirmed same tech so i told him to not let that guy near my truck again.

About the MAF, the writer said it was dirty and thats why it failed likely because i didnt change my filter enough. Except ive changed my filter at every other oil change. The theory that some debris entered when the tech did the compressor service seems very likely now.


Also an interesting note. When i broke down the truck was going 44mph on a maine winding back road and had no symtoms just died like key or fuel was shut off.

I had to be towed off the road, then a flatbed came and got me and took the truck to the ford dealership.

The service writer wrote that the truck came in with a service engine light as the complaint even though i made it clear that it died in the middle of the road and had to be towed in.

Probably time for another dealership but im guessing ill find more of the same.
I know a guy in Louisiana that could help ya out 😂
 
  • Like
Reactions: 3 users

The Evil Twin

Well-known member

Equipment
L2501, LA526,
Jul 19, 2022
2,402
2,323
113
Virginia
About the MAF, the writer said it was dirty and thats why it failed likely because i didnt change my filter enough. Except ive changed my filter at every other oil change. The theory that some debris entered when the tech did the compressor service seems very likely now.
2020 F350 with 7.3 gas, 25k miles.
Unless you are often the last truck in a convoy traveling down the trails in the desert, you should not have had to change your air filter at all yet. Aside from this fact, a dirty filter traps more particulate than a clean one. So, it actually makes the leaving air cleaner than would a new one. At the expense of flow, of course. That guy was trying to blow smoke up your butt.