TEST 4: TPS Code Won't Go Away
So you've tested the TPS per the instructions in this tutorial and according to the test results, the TPS is good... yet the check engine light is still on. Well, here are a couple of suggestions that might inspire your next diagnostic move:
- The throttle plate's idle-stop screw's factory adjustment has been altered so that the engine could be idled up and mask a miss/misfire and/or rough idle. This increases the TP sensor's signal to the PCM. The PCM doesn't like it and lights up the check engine light (CEL).
- The throttle cable is binding and causing the throttle plate to not fully close.
- This can be verified by simply having someone inside the vehicle pushing the accelerator cable to the floor and releasing it, with the engine OFF, while you visually check that the throttle plate and cable are not getting stuck somewhere in their travel.
- The TPS is failing intermittently. Which means that it works fine most of the time, but every now and then it doesn't:
- I have found that the best way to test these intermittents is to road-test the vehicle with the multimeter hooked up to the TP signal Wire with a long wire so that I can comfortably observe the signal going up and down as I or someone else drives.
- The TP sensor's connector is BAD, usually the locking tab is broken and the connector has worked itself loose, causing an intermittent false connection.
Where To Buy The TPS And Save
The throttle position sensor (TPS) isn't an expensive part... especially if you shop for and buy it online.
The following links will help you comparison shop for the throttle position sensor (TPS):
Not sure if the TPS sensor above fits your particular GM vehicle? Don't worry, once you get to the site they'll make sure it fits and if it doesn't, they'll find you the right one.
If this info really saved the day, buy me a beer!