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milomilo 07-21-2019 05:20 PM

Check Engine Light
Headed out of town yesterday when the 2004 Dodge Cummins 5.9 Check engine light comes on and it goes into limp mode. 10 seconds later it goes back into normal throttle. Light stays on engine runs perfectly. Stop and turn off engine, wait 30 seconds and restart, Light still on. Drive home running fine.

Started the truck this morning, no light and runs fine. Download codes at O'Reilys Auto.

P2121 and P2122.


It showed up 6 times on the reader. All codes were deleted.

Wondering if it is a bad connector or bad sensor.

Ironman 07-21-2019 05:30 PM

I would check the plugs first, if it continues, you have a TPS issue.
A little water in the plugs can go along way.

MetalWolf 07-21-2019 09:28 PM

Ran across this a few weeks ago on a buddy's 05 Dodge Cummins
the plug was dirty and I cleaned it seemed to go away after cleaning it...
then early this morning it came back plug was still clean and seated good sensor went bad so we replaced it and then went and picked up my bike from the dealer... and had no problems over to the dealer and back home.

So it could be just plug needs to be cleaned or the sensor is going bad.

flametamer 07-22-2019 06:56 AM

It seems to be a know issue. Check this page for info. He seems to have it figured out.


milomilo 07-22-2019 08:49 AM


Originally Posted by flametamer (Post 739067)
It seems to be a know issue. Check this page for info. He seems to have it figured out.


Thanks. I have already watched that video on calibration.

milomilo 07-22-2019 08:10 PM

Ordered the new TPS with a new wire harness today. $32 off Amazon. New one from Dodge is $580. Hope the Chinese one holds up.:)

flametamer 07-23-2019 06:38 AM


Originally Posted by milomilo (Post 739090)
Hope the Chinese one holds up.:)

If not I would go with his for $165 way before I would buy stock.


milomilo 07-23-2019 08:34 AM

He does have a lot of info on his page. Was interesting reading. Thanks.

Gadgeteer 07-24-2019 02:52 AM

I fixed our microwave oven a few years ago by disconnecting and re-connecting as many of the spade connectors as I could find. Failed 2 weeks, later. Unhooked spade connectors, again, and re-crimped all. Oven has been flawless since then.

Every few years our forced air furnace has stopped working. Same procedure of the few spade connectors is the remedy.

Suspect galvanic corrosion to be the culprit in both cases.

First thing I do, following failure of electrical/ic devices is to fiddle with all connectors. Most of the time it works.

milomilo 07-28-2019 01:31 PM

Bad News/Good News. Bad is the sensor I ordered did not come with slotted mounting holes therefore cannot adjust the idle voltage. It is boxed up and ready to return. Good is the new one I ordered today has the slotted holes and is $10 cheaper.:)

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