What to check first?

Jeney · Post by **Jeney** » 10 May 2017, 18:36

I'm getting a DTC of ECM:120D.

Possible sources listed are:
Air leakage in the intake system
Contaminated throttle body
Blocked intake system
Damaged MAF

I just fixed my MAF a few months ago (thanks to Volvo forums!) so that's in the clear. ETA: Maybe it is my MAF? Can you tell by looking at it? Is there a test to check if it's working?

My question is: where do I begin? I don't know how to do any of this, but I'd rather learn the most likely solution first.

It was running okay until it wasn't. Stalls immediately after turning on. Prior to this, I thought it might be my transmission because it hesitated at times. (It's not. My transmission guy is who pulled the codes for me.)

I'm beyond broke, so I'm hoping it's a cheap/free fix. And I'm hoping to fix it, like, yesterday.

Help?

bikerbob951 · Post by **bikerbob951** » 11 May 2017, 14:18

I'd start by unplugging your MAF and starting the car, does it behave differently? Also might want to try an ECU reset, I've read that sometimes that's necessary when messing with the MAF. If not that, have you removed the air intake filter box and inspected for blockage? I'm not terribly familar with these cars yet, but if it stalls immediately after starting and seems to make no effort to run, I'd say something electrical is stopping the engine from running. If it were a blockage or a leak, it would probably stumble and choke and then die.

Jeney · Post by **Jeney** » 11 May 2017, 23:02

bikerbob951 wrote: ↑11 May 2017, 14:18 I'd start by unplugging your MAF and starting the car, does it behave differently? Also might want to try an ECU reset, I've read that sometimes that's necessary when messing with the MAF. If not that, have you removed the air intake filter box and inspected for blockage? I'm not terribly familar with these cars yet, but if it stalls immediately after starting and seems to make no effort to run, I'd say something electrical is stopping the engine from running. If it were a blockage or a leak, it would probably stumble and choke and then die.

Oh, it does stumble and die. It tries! Later, it stayed on for a bit but it was suuuuuuuper rough. Then died.

I did check the air filter. I was really hoping that was it! Clean as a whistle. I tried replacing the MAF sensor (last time I just cleaned it) but it didn't help. Wish I'd known about the unplugging thing before I spent all that money I don't have on the sensor!

What about a smoke test? Would that help find the problem?

I just looked up what an ECU reset was. I wish I could go try that right now! I hope it's as simple as that.

Post by **abscate** » 13 May 2017, 05:43

That's an air mass error , same as P0114. I think it relates the air temperature component in the MAF.

Make sure the connector is clean and firmly seated.

Did you get an exact OEM REPLACEMENT when you changed it? After markets have a poor success rate.

Jeney · Post by **Jeney** » 13 May 2017, 15:14

Honestly, I got the cheapest one because it's all I had the money in my account for.

I want to try to reset the ECU, but, and this is embarrassing, I am kinda scared to. Once I finally located the battery, I wasn't sure what to do next. Unscrew the things that connect to the battery (negative first, right?) and touch them together for ten minutes? Then turn key to the second position before reconnecting?

Jeney · Post by **Jeney** » 13 May 2017, 15:27

Ok. My car runs fine when MAF is unplugged. So I checked the connector (the part that plugs in to the sensor) and it looks to be missing a prong. Could this be the problem?

Jeney · Post by **Jeney** » 13 May 2017, 15:35

The auto part sites say there are no MAF sensor connectors that work with my car.

ETA: There are only supposed to be that many prongs. Now I know that!

Post by **abscate** » 13 May 2017, 16:33

Post up,the part number for your MAF, original equipment.

If your scour the internet, you can find the wiring diagram for your year/car. MVS has a legal agreement without Volvo nit to host them here.

Buying cheap parts for these cars is tempting but not a good strategy. I know that's tough love but we have a lot of experience herewith where you cheap out, and MAFs aren't one of them

Jeney · Post by **Jeney** » 15 May 2017, 18:52

I took the advice I found here and bought a Bosch MAF, which will be ready for pick up on Wednesday. Sunday, I thought, what the heck, I'll peruse Pick n Pull to see what I find. A Bosch MAF! I bought it (with the warranty. Mama didn't raise no fool) and installed it, and my car ran perfectly! (MPGs wayyyy up. Almost suspiciously so.)

Today, one day later, I'm driving home from work and it starts doing the same thing when I stop at a light - stuttering, acting like it's about to stall.

What are the chances that I bought a used MAF with exactly one day of life left? Or is it just not the MAF at all? Or the MAF and something else?

Any advice appreciated (as always) as I need this car to live. Game over for me if I can't fix it!

Jeney · Post by **Jeney** » 15 May 2017, 21:56

Just noticed that I have zero oil in my car. Dipstick bone dry after second insertion. Sludge when I first removed it. I had it changed about six months ago. All my reading points towards clogged pcv. Totes can't fix that myself. Could that be at least a partial cause of my idle/stalling problems? It ran fine until the engine got hot.