[jdwatson]

Hello group. Newbie here and pretty green when it comes to really working on cars. I have a 2006 9-3 2.0T combi.

Recently went into a temporary "limp home" mode and pulled 2 codes P1681 and P0223. From other threads, most everything is pointing to a bad TPS but others are saying it could be the ecu and that the TPS could be false fault.

I cleaned the throttle body and replaced a bad o-ring on a mass air flow sensor (the one before the throttle body). I reset the codes and so far (about 2 days) the check engine light has not come back on and it drives great. Not convinced I really did anything of real significance though (TB was actually pretty clean already).

Before I dropped $400 on a new throttle body assembly I wanted to test the specs on the TPS to make sure it was actually bad. I have a multimeter just don't know what pin combination to test or what it should read. Can anyone provide info how how to test the TPS. Any help would be appreciated.

 

[Vision i.T Services]

"how to test the TPS"

Carefully... short a wire and you'll blow the module.

You need wiring piercing probes for a start (or a bent paperclip), as the connector needs to remain connected in order to get a proper reading (you could just ohm each one out though, at a push)

There are two sensors in the TB. They must total 5V (4.96v usually). As one sensor voltage drops, the other must increase to fill the gap. So if one reads 3V, the other must read 2V for example. There are 3 wires - a ground (which should read no more than 0.1v, a reference wire which should be 5v all the time and a signal wire which fluctuates with the throttle.

There's a 4% tolerance at idle, 8% at WOT. If it goes outside those values, even for a nano-second, it'll throw a code. Trouble is, cheap digital multimeters usually aren't fast enough to detect the drop... analogue ones would.

While connected to the signal wire, press the throttle very gently all the way to wide open. You should see a steady increase in voltage on the meter. If it jumps or hangs, there's a problem. Likewise if you get a negative voltage, there's a short to ground somewhere in your wiring or at worst, the CIM is knackered.

 

[jdwatson]

Thanks. That seems a little above my ability with pretty severe problems if I screw it up.

Thanks anyway.