Throttle Position Sensor

grr · Post by **grr** » 02 Feb 2012, 09:56

1998 S70 T5 290k/miles.

Could not read the check engine light code at the local parts store, so I went to the Volvo dealer (US$126 HOUR !) though they read it at no charge. They did not say what the code was, but told me it was the throttle position sensor and that they wouldn't have time to repair it that afternoon (I had not asked them too). Does it take a long time?

I've never cleaned the PCV system and it has never exhibited any problems.

What is the throttle position sensor and where is it? Other than this sudden appearance of the check engine light the vehicle runs fine.

Thanks in advance,
Jerry

Post by **jblackburn** » 02 Feb 2012, 10:11

It does exactly what it sounds like - senses how much your foot is down on the gas. The car uses this information to determine air/fuel mixture and auto transmission shift patterns.

It's on the very front of the throttle body.

Post by **tjts1** » 02 Feb 2012, 11:31

Its amazing to me that Volvo dealers get away with such horrific customer service.

grr · Post by **grr** » 02 Feb 2012, 14:05

I can't see anything familiar on my S70, which is a 5-speed. Is the stick shift different or is the switch buried beneath the accelerator cable unit?

(Yes, they use lots of winter salt up here in Wisconsin)

Post by **tjts1** » 02 Feb 2012, 14:39

The TPS is mounted on the opposite side of the TB shaft. Its black plastic attached with 2 screws as in the pic posted by jblackburn. You'll probably need to remove the intercooler hoses to see it clearly. Since there is so much salt on the roads in your area, you might get away with simply disconnecting the plug and cleaning the oxidation on the contacts with some fine grit sand paper. Then reset the codes and see if the problem comes back.

grr · Post by **grr** » 02 Feb 2012, 17:34

Thanks guys...I'll order the part.
Jerry

Post by **bigdaddylee82** » 02 Feb 2012, 17:42

Try what tjts1 said before ordering a new one. Pull the current one off, get a can of CRC Contact Cleaner (or similar) a wire brush, and go to town on the contacts on the sensor and it's cable. When you put it back together use some dielectric grease. I'm 90%+ sure that'll fix it. If it doesn't, you'll want to clean the cable contacts and use dielectric grease on the new one anyway, so nothing to loose for trying.

- Lee

grr · Post by **grr** » 02 Feb 2012, 17:54

Oh...I didn't see his comment. That's good advice, especially in this climate.
Thanks,
Jerry