How To Test The TPS (1991-1995 3.3L Grand Caravan And Grand Voyager)

The TPS Code Won't Go Away

In some cases, the fuel injection computer refuses to believe that the TPS is good and continues to set a TPS diagnostic trouble code. This TPS trouble code in turn keeps lighting up the check engine light.

If this is happening to you, here are a couple of suggestions that might inspire your next diagnostic move:

1. 1

   The throttle plate's idle-stop screw's factory adjustment has been altered to rev up the engine (see photo above).
   
   This is usually done to increase the engine's RPM at idle to mask a rough idle problem. This increases the TP sensor's signal to the fuel injection computer. The fuel injection computer doesn't like it and light ups the check engine light (CEL).

2. 2

   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 pedal 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.

1. 3

   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 intermittent problems 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.

2. 4

   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.

More 3.3L V6 Dodge Grand Caravan And Plymouth Grand Voyager Tutorials

You can find a complete list of tutorials in this index: Chrysler 3.3L Index Of Articles.

• How To Test The MAP Sensor (2001-2004 3.3L V6 Chrysler And Dodge Mini-Van).
• How To Test The Alternator (2001-2007 3.3L Chrysler).
• How To Test Engine Compression (1991-2007 3.3L V6 Chrysler, Dodge, Plymouth Mini-Van).
• How To Test The Coil Pack 3.3L, 3.8L Chrysler, Dodge, Plymouth (at: easyautodiagnostics.com).