Overdrive stopped working
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Registered User
Joined: Apr 2011
Posts: 1
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Overdrive stopped working
Hoping someone can offer advice .. I have a 2003 3/4 ton 4WD..5.9l Cummins, auto. trans.. All of a sudden the transmission has quit shifting into overdrive.
Took it to a shop..they get the following codes ..
P0700 - trans. fault present
P0123 - TPS voltage high
P1596 - speed control switch always high
Scan dtat shows the tps voltage staying at same voltage no matter where throttle is positioned.
Shop technician says cruise control seems to not be working either, although I never use it.
They claim that when they 'wiggle' the connectors at the PCM and A/T(whatever that is) the tranny then shifted properly. Stopped vehicle...road test again...back to no overdrive.
They want to replace the PCM?..is that the computer?...$1200!!
Lately I've also noticed that after starting the truck...headlights surge for a minute or two..amp guage reads under 14..till engine kicks to high idle..then volt meter goes from roughly 12...up to 16...headlights stop surging. Is that normnal after the draw from engine warm and starting? Could that have to do with the non-overdrive issue? Anythoughts at all would be greatly appreciated.
Took it to a shop..they get the following codes ..
P0700 - trans. fault present
P0123 - TPS voltage high
P1596 - speed control switch always high
Scan dtat shows the tps voltage staying at same voltage no matter where throttle is positioned.
Shop technician says cruise control seems to not be working either, although I never use it.
They claim that when they 'wiggle' the connectors at the PCM and A/T(whatever that is) the tranny then shifted properly. Stopped vehicle...road test again...back to no overdrive.
They want to replace the PCM?..is that the computer?...$1200!!
Lately I've also noticed that after starting the truck...headlights surge for a minute or two..amp guage reads under 14..till engine kicks to high idle..then volt meter goes from roughly 12...up to 16...headlights stop surging. Is that normnal after the draw from engine warm and starting? Could that have to do with the non-overdrive issue? Anythoughts at all would be greatly appreciated.
Professional
Joined: Nov 2009
Posts: 129
Likes: 0
From: ontario, California
Sounds like the pcm is going bad. It will start shutting all the gauges off and running kinda rough after awhile. Id personally say its the pcm. Its happend to me You can send it in and have it rebuilt compared to spending the 1200 for a new one. But yea. Good luck.
