Code P0120 - Throttle Position Sensor

Dmck · Post by **Dmck** » 07 Aug 2018, 08:11

Hi all,

So after battling my car back from the grave (blown head gasket from broken water pump propeller) all I have left as a check engine code is for the throttle body position sensor

I already went to junkyard and switched out the throttle position sensor with another one. It could be possible I used a bad one again...

Other than it being the sensor itself, what other issues could be causing this code to fire?

It would be great to not have the check engine lights glow burning a hole in my brain.

Post by **erikv11** » 07 Aug 2018, 13:14

How is the TPS connector on the wiring harness, and the little pigtail back to the main harness? Maybe a wire got pinched etc.

How about the fuel relay under the radiator cowl, is it connected well and its connector not falling apart? I have read of problems with this relay affecting the TPS, but I've never checked out the wiring diagram to try to understand why.

Dmck · Post by **Dmck** » 07 Aug 2018, 13:29

I'll look into it. I fooled around with the wire a tiny bit this morning and reseated it into the TPS

When I first start ignition the check engine light isn't on. It takes a second to click on.

If I start the engine and then rev it or take out of park, it turns on right at that moment of either of those actions.

If it were wiring I would think it would be an automatic check light and not delayed, but not sure.

I'm going to take off the intercooler tube tonight and fiddle

Post by **misha** » 07 Aug 2018, 15:17

Dmck wrote: 07 Aug 2018, 13:29 ...If it were wiring I would think it would be an automatic check light and not delayed, but not sure...

No...the ecu will need to go through about 3 check cycles before it sets check engine light ON.

marcello916 · Post by **marcello916** » 30 Oct 2025, 11:53

Dmck wrote: 07 Aug 2018, 13:29 I'll look into it. I fooled around with the wire a tiny bit this morning and reseated it into the TPS

When I first start ignition the check engine light isn't on. It takes a second to click on.

If I start the engine and then rev it or take out of park, it turns on right at that moment of either of those actions.

If it were wiring I would think it would be an automatic check light and not delayed, but not sure.

I'm going to take off the intercooler tube tonight and fiddle

did you ever figure out the issue? i have the same problem right now and the check engine lights is annoying me