1994 Volvo 850 Turbo TPS symptoms

Skatehouse · Post by **Skatehouse** » 27 Aug 2007, 09:00

Hello Matthews users, glad to be here!

Could anyone tell me the sypmtoms of a a faulty Throttle Position Sensor?
Is it normally suppossed to have a clicking sound?

Thanks!

Skatehouse · Post by **Skatehouse** » 27 Aug 2007, 10:50

Sorry, didn't mean to post 2X

Post by **billofdurham** » 27 Aug 2007, 11:36

Welome to Matthew's Volvo Site.

I have deleted your duplicate post.

The TPS should click just as it opens.

If you think there is a problem with it have you read the fault codes, if any?

Suggest you download the 850 manual pinned at the top of this forum to see how to read the codes, if you don't already know. .Pdf file 'Tests with codes turbo' has a full how-to. Although it is headed for '95 models it applies equally to yours.

Bill.

Skatehouse · Post by **Skatehouse** » 27 Aug 2007, 11:40

Posted code PO120.
I pulled the switch, no clicking at all.
Ordered a new one just now. I will post results.
So this switch will make my car shut down?
I've been having problems with my car shutting off randomly in very precarious situations. Any insight?

Skatehouse · Post by **Skatehouse** » 27 Aug 2007, 14:28

Cleared out codes-
Installed NEW TPS switch-
Still no go...no spark at the coil.
Voltage going in, none coming out.
Read codes...same thing
P0120 (TPS faulty)

any ideas?

Post by **Ozark Lee** » 27 Aug 2007, 15:11

Voltage going in, none coming out.

Sounds like the coil quit on you. The Ohmmeter tests are to disconnect one of the primary coil wires and then measure between the two primary leads. The resistance should be 0.3 to 0.7 ohms. Then measure between coil terminal 15 and the high tension socket. That should be 8,000 to 9,000 Ohms. All of this is done with the key off.

If that checks out move back to the power stage. With the key in position II you should read battery voltage on pin 3. If that checks out turn the key back to off and use the ohmmeter to measure between pin 1 and ground, you should read 0 ohms. I doubt you have a frequency meter but we can make observations at the next stage. Measure the voltage between pin 4 and ground on DC volts. Crank the car over and the voltage should jump at an 8 to 10 times per second rate.

A failure of any of those tests indicates a faulty power stage or a faulty crankshaft position sensor. Does the tach. bounce when you crank the car over?

...Lee

Skatehouse · Post by **Skatehouse** » 27 Aug 2007, 19:28

Mr Ozark, thank you for your wonderful technical help. I was really at my witts end. I was about to call it quits and take the car in when I noticed a little red wire (12ga) that was hanging loose by the battery (+). It had corroded itself off the terminal. All the intermittent, on/off B/S was from the wire jiggling itself loose. Just enough to "run" at times and then not.
I reattached the wire and Vrrromp! There it is! I Feel SO STUPID! But then again, why is my car throwing the same P0120 code? Maybe it will clear out? Anyhow, thanks for your wonderful input.

phoenix_iii · Post by **phoenix_iii** » 28 Aug 2007, 07:07

Skatehouse wrote:Mr Ozark, thank you for your wonderful technical help. I was really at my witts end. I was about to call it quits and take the car in when I noticed a little red wire (12ga) that was hanging loose by the battery (+). It had corroded itself off the terminal. All the intermittent, on/off B/S was from the wire jiggling itself loose. Just enough to "run" at times and then not.
I reattached the wire and Vrrromp! There it is! I Feel SO STUPID! But then again, why is my car throwing the same P0120 code? Maybe it will clear out? Anyhow, thanks for your wonderful input.

You need to clear the codes out manually. [Do not believe there is an auto clear after 60 starts/no detects like old bmw]