Signs of a failing ETM and its relation to the MAF sensor

[Jacko3245]

i think the ETM might be going out on my 2001 V70 2.4T. heres the rundown. The Check engine light is on (was on before though),, no oil pressure light on (only when warm except for about 2 days before the knocking and would go on and off several times while i drove. called a volvo dealer they said it was ok and not to worry) the vehicle has about 181,135 miles on it and hasnt been serviced since 130,000ish miles. the knocking sound was there the whole way home. i live 3 miles from work and it took me 20 minutes to get home going 20 MPH (wouldnt let me go faster. the fastest i could go was about 30MPH but the knocking was really loud at 30 MPH) A mechanic came to look a few days later and it still knocked. then the same a few days after that. i purchased the vehicle used and it then sat 4 months then we jumped it, got a new battery and started it weekly but didnt drive it for 2 more months. i started driving it 6 months to the day since we had gotten it. where i live, traffic is crazy so to get out of my neighborhood i have to hit the gas pretty good. it takes a second to go. ive done some research. could it really be the ETM?

[moco292]

I recently bought a 1999 V70 non Turbo Wagon from a friend whose mechanic said she would only need to replace the ETM and the car would run fine i replaced it with an exact number and color matching label used one. Well yes it fixed it to a degree, it actually accelerates now as before stepping on the gas pedal produced no acceleration at all it would only idle it's way along. The problem now which my mechanic and i are looking into is it accelerates poorly, roughly bucking until it gets up to some speed and then as long as i don't depress the pedal too quickly it is driveable until i need more power for a hill etc. Check engine light is on. He seems to think this car has some kind of gas pedal sending unit which operates the ETM, Any hints or clues would be helpful. I posted to this thread since it seemed closely related. Thanks

[matthew1]

Step one: read the codes.

[precopster]

Same year and model doesn't mean it has the same firmware fitted.

If it has throttle codes it could be vwrong firmware. The codes unfortunately don't give that info away. They will just be throttle codes.

If you still have the old ETM you can have someone with VIDA read the old unit and tell you if new unit's firmware matches.

[abscate]

I recently bought a 1999 V70 non Turbo Wagon from a friend whose mechanic said she would only need to replace the ETM and the car would run fine i replaced it with an exact number and color matching label used one. Well yes it fixed it to a degree, it actually accelerates now as before stepping on the gas pedal produced no acceleration at all it would only idle it's way along. The problem now which my mechanic and i are looking into is it accelerates poorly, roughly bucking until it gets up to some speed and then as long as i don't depress the pedal too quickly it is driveable until i need more power for a hill etc. Check engine light is on. He seems to think this car has some kind of gas pedal sending unit which operates the ETM, Any hints or clues would be helpful. I posted to this thread since it seemed closely related. Thanks

Moco - it sounds like the mechanic doesn't have any experience with the Electronic throttle System on Volvo and should not be giving advice on it. You have to understand all the system components and software to work on these or else you will fail. They are expensive to fix, but once fixed, last 100,000 miles without service. Mine went 137,000 before replacement.

Rough running could be lots of things - loose hoses, bad coils, plugs - all stuff which has to be ruled out before you dive into ETM issues.

You can't just replace it with the same part number - software in the car and ETM have to match, too.

[precopster]

He replaced the ETM without matching the firmware. The same yellow label with the same part number takes around 30 different firmware versions.

29 of them will provide pedal response and run your car really badly.

WITH IGNITION IN POSII AND ENGINE OFF THE ETM NEEDS TO SHUT OFF AFTER 8 SECS AND BE SILENT. IF NOT YOU HAVE WRONG FIRMWARE.

[Mojobaby27]

Is it possible to just replace the resistance strip from another car at the junkyard and maybe get yourself another couple years?

[abscate]

People have been successful doing this but it is delicate work with a soldering iron from what I have read.

FCP Euro is now carrying these rebuilt for under 400, with a 100 software fix you can be back up for 500 or so.

[abscate]

Missed this one but adding for completeness.

The software fix doesn't do anything to hardware - it just lets the ECU accumulate 10 errors before tripping the ETS light instead of 5. The throttle body on white and yellow label ETMS is the same too. (Im making up the 10 and 5 numbers above, I don't know the actual error count flags)

Yes, thats right, Volvo implemented a software fix that just turned off your ETS light during warranty without fixing the problem. Plenty of other places to rant about that - lets not start another.