Question on Throttle Body Sensor - 1999 S70

JohnG1965 · Post by **JohnG1965** » 15 Apr 2026, 10:29

Hello all,

My daughter's car. She recently had the heater core fail. Mechanic replaced (only because she panicked and had it towed there. i could have done it). Any way, after repair she starts driving home and it starts sputtering and bucking.

She brings it back and he suspects throttle body problem. Cleans it, no luck. Replaces it, no luck.

He also told me the vehicle is not recognizing his OBD scanner. That's new because I know I've used mine on it in the past.

I know he's not scamming me because he did all that and just towed it to my house at no charge. I ordered a new throttle body position sensor to try that for cheap.

Any ideas? It's in my driveway now with the battery disconnected to see if that resets and computer issues.

Thanks in advance.

JohnG1965 · Post by **JohnG1965** » 15 Apr 2026, 14:15

Update - I just checked the throttle body and the flap was stuck open. I cleaned it best I could. I started the car (or tried to multiple times). No start and strong smell of gas. I checked the throttle body again and was was stuck open.

The mechanic told me he replaced the throttle body and the car acted the same way. He did not mention that it was stuck open, but the guy i spoke to is tow truck driver and another guy did the work.

I believe he did install a new one and put the old one back on..He showed me the package where he was returning it and didn't charge me for the work.

Post by **abscate** » 15 Apr 2026, 18:56

The 1999 throttle body is electronic and needs software to match the ETM or ECU software . It is not just a hardware swap.

See the ETM Room forum below

Quick test…put hood up , have your assistant turn the key to position II, but don’t start engine.

The throttle body should click and whine for about 6-8 seconds then click and stop whining. Ifor doesn’t do this, the software isn’t right.

Post by **scot850** » 16 Apr 2026, 00:00

What model of S70 do you have? Non-turbo (Base/SE), Low Pressure Turbo (LPT/GLT) or High Pressure Turbo (HPT/T5)

There are a few things that could have gone wrong, possibly the repair guy could have caused it (Overzealous use of throttle body cleaner, or using carb cleaner can damage the throttle body position sensors. It may have crapped the bucket as they will do at some point due to age and the position sensors wearing out.

Unlikely to help, but maybe try disconnecting the battery and touching the 2 leads to drain the electrical system. Then try reconnecting the battery and see if the throttle body can reset itself.

If you can find a throttle body from a car with the same engine (as listed in the 3 options above), you can usually just swap them in and they will work. If you connect it to the car and switch the ignition on, you should get the whirring sound for a few seconds and the throttle plate should move to find it's home position.

Or Abscate I believe says there are refurbished units on EBay that care not too expensive.

Lastly have someone like Xemodex repair the ETM.

Neil.

JohnG1965 · Post by **JohnG1965** » 16 Apr 2026, 04:40

Thank you both for the responses. It is a base SE model.

My lovely assistant will not be available until Friday after work. I should have the new position sensor delivered by then.

Since I still have the original throttle body installed, would a new sensor still require a software update?

Post by **abscate** » 16 Apr 2026, 06:09

JohnG1965 wrote: 16 Apr 2026, 04:40 Thank you both for the responses. It is a base SE model.

My lovely assistant will not be available until Friday after work. I should have the new position sensor delivered by then.

Since I still have the original throttle body installed, would a new sensor still require a software update?

Soy confuso - the 1999 models dont have a position sensor like the -1998, all the sensing is done internally to the Electronic Throttle Body

Can you post up a picture or part number of the thing being replaced?

JohnG1965 · Post by **JohnG1965** » 16 Apr 2026, 06:37

: Screenshot 2026-04-16 083257.png (24.52 KiB) Viewed 281 times

I ordered from Parts Geek. According to their website, there are half dozen different brands for this.

Post by **abscate** » 16 Apr 2026, 06:46

I think that is the 1998 version and wont work on a 1999 unless you have some FrankenVolvo going on.

If you dont have a mechanical cable running over top of your engine to the rear of the block (left side of car, facing forward, but pretty much middle of engine bay) that sensor wont fit anywhere.

Diagrams attached

JohnG1965 · Post by **JohnG1965** » 16 Apr 2026, 06:50

OK, I'm at work now (clearly), so I can't check right away. Any other ideas on what might be forcing the flapper to open and stick when trying to start the car?

Post by **abscate** » 16 Apr 2026, 06:57

The 1999 is complicated, there is a processor in the throttle body which speaks Italian, and the ECU speaks German. A swedish interpreter in between has to tell each one what it wants.

The usual failure of the ETM is the contact stripes inside wear out, they start giving errors, and when 'enough errors' accumulate the ECU gives up and puts the ETS light on and puts you into 'limp mode' - about 15-20 mph to roll home.

If the blade isnt passing the self test above its probably going to need replacement

There are some fixes on IFixit if you want to go gorilla and open it up - I dont do this as I have six ladies driving in urban traffic and Im usually in Singapore when they break