I keep getting the two TPS codes for some reason. My test lights light up when they're plugged in, meaning the ECU sees the TPS.

I took the resistance of the short-range TPS while the engine was cold, and it was too high (1.35K ohms instead of 1.2 or less). I think maybe the cold weather means the thermowax is putting the TPS out of range, but I wonder just how wide of a range does the thermowax have? I have a hard time finding that maybe a 15-degree difference in weather would effect something like the thermowax.

It couldn't possibly have enough heat/movement range to make that much of a difference, could it? Or maybe the fast idle cam needs to be adjusted?

Idle settings (on the S5 NA at least) do seem to effect the TPS (if you adjust the timing you'll have to adjust the idle, and if you adjust the idle you'll have to adjust the TPS), and at the moment I have a vacuum leak I can't find (I have my suspicions but haven't pinpointed it yet) so the idle screw is nearly at full out (highest setting, although it doesn't make much of a difference since the idle adjust doesn't work when there's a vacuum leak), and maybe that's the culprit? (actually I have already realized that's probably it sort of seems like a shame to erase what I already wrote )

Anything is better than having to pull the harness and repair it...

 

The TPS read high because the cold thermowax has opened the primary throttle a bit, exactly as it's supposed to. You only check the TPS with the engine (and hence the thermowax) hot, so that the thermowax doesn't affect the reading.

 

I know. What I want to know is if it would open it more on say a 60-degree day versus a 75 degree day, and by how much.

There's gotta be a point where it won't open any further.

 

It ain't weather related. It's WATER temperature related as to when the fast idle cam comes off the roller and no longer effects the throttle linkage.

But then again it is weather related IF your talking about letting the car sit overnight and then read the output of the TPS. In the summer the output of the TPS to the ECU might be in the range of say 1.5 volts with a cold/non started engine. On a winter day of 32F, the output might read 2.7vdc on a cold non started engine.

Both those examples are NORMAL and the car/engine/ECU were designed that way.

That's why the TPS should only be set with a HOT engine. With a HOT engine the fast idle cam has come off the roller..........unless someone has fiddle fucked around with the settings of the screws.

Normal output of the TPS is approx 1vdc with a HOT engine with the cam off the roller. IF the cam isn't off the roller with a HOT engine, then things need to be put right again. Done

 

Well, according to my DMM, both the pressure sensor and the TPS are fine, but for some reason the codes still won't go away.

According to the FSM that means I have a FUBAR'ed ECU, assuming that the pressure sensor getting the right voltage means the harness is ok (I would think it does).

I guess I'll pull the ECU end up into the engine bay and check them sometime soon (not to mention the split air solenoid valve, not that it matters seeing as how I have no split air hose). And I guess I need to check the ECU voltage as well...

Funny, I found my vacuum leak, and it's a hose that has caused vacuum leaks about 5 times before... I need to get clamps on it (besides that, the hose I bought was a bit too big...).

 

The roller on the throttle linkage comes off the fast idle cam at about 65degC/150degF coolant temp, so basically even before the engine has fully warmed up the thermowax is no longer having any effect, and does nothing until the engine is turned off and cools down. Ambient temp has no effect on this whatsoever.

The error code simply means the ECU is not seeing the expected signal. It could be a dirty or loose connector or a broken wire, both of which as likely or even more likely than an ECU problem. Just because the sensor is receiving the right voltage, doesn't mean the ECU is. You need to check the signal voltage at the ECU as per the FSM tests.