Brian Gray

96 XJ 4.0, just installed my 3rd TPS unit in a year. I'm at a loss as to what would be causing them to fail...

XJlimitedx99

Mopar or Chinesium sensors?

Do you have hood vents or anything else that would cause them to get wet?

Brian Gray

Only Mopar parts. No hood vents

Cummins93

In what way are they failing?

Brian Gray

First time, idle was very erratic, check engine light came on.
Replaced it, ran fine for several months then, every once in a while after putting it in park it would idle up. I woukd bump the throttle and it would return to normal idle. Drove it for months like that. It did it again yesterday and I couldn't get the idle back down( about 1200-1500 rpm). So I just shut it off. After a few hour's, started it to go home and idle was erratic again and throttle had alot of lag. Got out of the parking lot, engine light came on again and would not shift past second. Cide was for the TPS. Replaced it again and now runs fine.

fb97xj1

Remove and clean the throttle body (try not to tear the gasket) along with the IAC. Inspect the TPS connector for signs of corrosion, pinched wiring and any breaks in the insulation, between the connector and the plastic wire loom. Make sure the wiring is not rubbing against the ground strap stud back there. It may not be an issue here, but cleaning the engine grounds never hurts.

What was the exact code?

Brian Gray

Can't remember the exact code. I did replace the IAC and clean the throttle body the first time I replaced the TPS. Connector looked fine when plugging in the new one yesterday. May have to look closer at connectors and chase down the grounds.

Cummins93

With an obd2 monitor with live data observe your idle tps% then depress the throttle slowly to WOT and observe the %increase. What is the max percent at WOT?

Also with a volt meter on the sensor output, should be orange/dark blue trace from connector A pin 23, measure the full sweep manually to see if the voltage increases smoothly. This is a key on engine off maneuver.