Sudden ETM or MAF Failure?

sbs70 · Post by **sbs70** » 23 Jun 2026, 05:20

I have a 1999 Volvo S70 with 166k miles on it. I’ve had it for around 2 years now, and I’ve had overall pretty good luck with it.

Ever since I bought the car, I did notice a bit of hesitation when pressing the gas, specifically at highway speeds or going uphill, but it happened every time I hit the gas, and I had no other symptoms and no codes, so honestly, I didn’t think much of it.

Yesterday, I made a 45 minute drive. The car ran perfectly fine during that whole drive. The car sat parked for around an hour. I got in the car to start it again and return home, and the second I started it, the check engine light came on, and the idle sounded horrible. It was bouncing rapidly and consistently between 800-1000 rpm. I shut it off and got it towed home, I didn’t want to risk further damage or putting myself in danger.

Got home and scanned the codes, I got P1031 and P1026 for confirmed codes, and P1017 and P1021 as pending codes. The ETS light has not come on yet, even after running it briefly a few times to attempt to diagnose it. Sometimes when I start it, the idle surges between 800-1000. Sometimes, it evens out at around 1000.

I’m at a loss because I’m having a hard time finding any reliable information. I keep hearing that because of the codes and symptoms, it’s definitely the ETS, but I keep hearing that the MAF can also cause these symptoms and codes. I find it odd that the check engine light is on, registering these codes, but the ETS light hasn’t come on yet. (And yes the bulb for the ETS light works

) I do know, however, that it is possible for throttle body to fail and ETS light doesn’t come on. I’m also shocked at how rapidly the failure was. No stalling, no extreme hesitation or noticeable idle hunting before.

I checked for vacuum leaks, didn’t find any. Tried the test of unplugging the MAF, which made no difference at all in how it ran. The throttle body was clean. I ordered a new MAF just to see if that would change anything. If that’s not the problem, I’ve heard that MAF fails shortly after ETS anyways, so it’s good to replace them both around the same time. If the throttle body is the issue, I plan on sending it out to Xemodex to have it rebuilt, so I don’t have to have the software reloaded. (Closest Volvo dealer is over 2 hours away

)

Has anyone else had anything similar with their S70? Any experience with failed ETM or MAF? Just looking for any info I can get in the meantime.

Post by **abscate** » 23 Jun 2026, 06:03

You have cloned my exact experience with Karla Kat, a 1999 s70 awd turbo model with ETM

Do the switch on test - in a quiet place , have someone turn the key on to see if the ETM does the self test….click….whine….5-8 seconds……clunk.

The definitive test fir ETM failure is done with Vida but I would say a symptom based diagnosis is probably 90% reliable

sbs70 · Post by **sbs70** » 23 Jun 2026, 06:07

This is exactly the kind of info I’m looking for! I’ll have to try this later today when someone else can turn the key. Thank you!

Post by **abscate** » 23 Jun 2026, 06:09

sbs70 wrote: 23 Jun 2026, 06:07 This is exactly the kind of info I’m looking for! I’ll have to try this later today when someone else can turn the key. Thank you!

If you are comfortable sharing your zip code or postal code we can see if anyone is close.

If your car is non turbo, ETM replacement is easy bolt on bolt off.

Turbo is a bit tricker.

My thread on this , ongoing repair right now! I had the same non-definitive ETM diagnosis, but notice I fixed a huge vacuum leak too!

viewtopic.php?t=108195

sbs70 · Post by **sbs70** » 23 Jun 2026, 06:12

That’s okay, I have someone who can help me with it in a few hours.

This is one of those times I’m thankful that it’s a non-turbo. I was looking at it yesterday and it looks very simple to replace.

Post by **abscate** » 23 Jun 2026, 06:14

Search on eBay for the newest version of the contact less ETM. Part number is in the ETM room forum here

You want to buy one from a non-turbo car - it will be less than half the price of a Xmodex rebuild

There is a gotcha on these. The wire for the ETM runs behind the starter mount so you have to remove the starter to get the plug put.

I cut my ETM wire as it was dead, but if you want it rebuilt You can’t do this, so add in that labor to remove.

You have to be careful on eBay buying this as sellers load every part number into the text to snare your search. If it says it works with all Volvos 1999-2001, it won’t.