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Edward
Edward, ASE Certified Technician
Category: Volvo
Satisfied Customers: 3023
Experience:  I've had 10 years of experience on the car line at 2 Volvo dealerships, Quality level Volvo tech.
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Volvo S60: I have a 2006 Volvo S60 2.5T AWD and the check engine

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I have a 2006 Volvo S60 2.5T AWD and the check engine light came on with a code for the MAF sensor so I replaced it and rest the codes and after a couple starts the check engine light comes back on. What else can cause the MAF sensor code to come up?

Edward :

Hello and thanks for your question. My name is XXXXX XXXXX I will do all I can to help.

Edward :

Let me first ask, do you know exactly which codes were stored?

Customer:

i think it was P0101

Edward :

that was it? just 1 code stored?

Customer:

it showed up twice

Customer:

one time there was a code about fuel rail

Edward :

alright, fuel rail pressure sensor maybe?

Customer:

meaning there is usually 2 codes both P0101 and sometimes there are 3 the other being the fuel rail code

Customer:

when looking at the fuel pressure on the scan tool is looks good and doesn't drop when running or stopped

Edward :

OK, This P0101 showed right back up after replacing the MAF though? and that was the only code stored at the last time you scanned it?

Customer:

yes.

Edward :

Alright, give me just a few minutes to look over a few things. thank you.

Edward :

I'm digging here, sorry to keep you waiting going through all data now. You may wanna check back in 5 to 10 minutes here. I wanna give you the best answer I can.

Customer:

ok

Edward :

I love the way they are real precise here in their possible causes.

Edward :











DTC Code:P0101
Description: Mass Or Volume Air Flow A Circuit Range/Performance
Probable Causes:

  1. Sensor or solenoid faulty

  2. Connector terminal contact is damaged or corroded

  3. Wire harness - Check harness for correct voltage, open, short to ground or short to voltage

  4. Update control unit software - Check for the latest control unit update

  5. Powertrain or Engine Control Module faulty

Edward :

that's what they have, I'm digging in the wiring diagram now, do you have a voltmeter

Edward :

ohm meter and a volt meter?

Customer:

yes

Edward :

alright, Here's a diagram of the MAF circuit, first thing to do is make sure the GREEN wire has battery voltage with Key ON.

Edward :

give it a second to load.

Customer:

ok right now there is a box with a broken page

Edward :

check it now.

Edward :

I see it when I click it.

Edward :

The VIOLET/WHITE wire at the MAF should have 5 volts reference voltage with key on engine off, when measure between that wire and chasis ground.

Edward :

And the GREEN wire should be battery voltage around 12 with key ON Engine Off.

Customer:

ok i see it now

Edward :

alright, MAF is at the top. you can blow it up with the + icon.

Edward :

image size

Edward :

when you monitor the MAF signal with your scanner. does it change with engine RPM? have you tried getting in that data stream/?

Customer:

yes it does

Edward :

So we can conclude that the wire from the MAF to the ECM is good then, and if you got a P0101 with 2 different MAF sensors, then we can also just about be certain it isn't the MAF itself.

Edward :

This sensor aftermarket ? or came from Volvo. (it would be a bosch sensor).

Customer:

i didn't get it from volvo but it is a bosch

Edward :

alright, going through what the causes of the fault code can be, I would verify correct voltage on GREEN and VIOLET/WHITE, and if they show 12 volts and 5 volts, I would smoke test the intake system, (sometimes these vacuum leaks on turbo's can be hard to find, that pipe that goes to the ETM under the intake has been known to melt from the inside out or crack and only leak under boost).

Edward :

If that pipe looks good and the voltage checks out, The only thing that is left is the ECM software bungled up and you need to update to the latest version, or the ECM itself which I highly doubt is defective.

Customer:

ok how do you do the smoke test

Edward :

One thing I like to do, is get somebody inside to stall test the engine, (FULL BRAKE and 1/2 throttle in D) to get some boost pressure in the hoses, then you can hear and feel around them and see if anything is leaking pressure.

Edward :

put the E brake on fully as well, and trust them. :)

Customer:

lol ok

Edward :

Smoke test takes a machine, similar to a fog machine at a concert. it pressurizes the intake system. alot of shops have them now. you take the fresh air hose off the MAF sensor and use an adaptor to pressurize all of the vacuum and turbo hoses with smoke liquid. then you just look for the smoke.

Customer:

oh ok

Edward :

best way to find vacuum leaks in my opinion. it takes a big leak on these to find it spraying carb cleaner around hoses and connections.

Edward :

Has it ever been updated to Volvo's latest and greatest software that you can recall? I swear I think they build some glitches in after 5 years or something. lol.

Customer:

yeah thats what i tried

Customer:

no

Edward :

Alright, that can "loosen" up the ECM a little so it doesn't look at everything so critical, expand the parameters a bit.

Customer:

yeah it has 161,000 miles

Customer:

ok i will check the voltages and for leaks. if everything looks ok i might have to bite the bullet and bring it to volvo

Edward :

I don't believe you have a wiring issue if you can monitor the MAF and the signal changes. and I don't think 2 sensors are bad. So I would say that either a software upgrade or you have a vacuum leak somewhere . I seriously doubt the ECM has an issue, it's a possibility, but I would be 99% sure it hasn't failed with just 1 code stored. I believe a smoke test for vacuum leak or software update fixes it.

Edward :

Yes, If you don't have an independent that can perform software downloads on volvo's then it will be a dealer only type operation. Some import independents have invested in VIDA system, but unless their Volvo specific they prob. don't do it.

Customer:

ok thank you

Edward :

Alright, thank you. have a good week.

Customer:

thanks you too

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