RTH - Replaced Battery and truck now won't idle!

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SanDiegoCruiser

SanDiegoCruiser

10 Year
Joined
Sep 14, 2011
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63
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1,244
Location
San Diego
I just got around to replacing my battery with a new Diehard Platinum 31 series.

The tuck starts fine but I have to keep my foot on the gas and keep the rps over 1K. If I let it idle, it will die. No CEL. Any ideas what could be causing this?

I even put the original battery back just to make sure and it does the same exact thing.

Help!

SDCruiser
 
Now it is throwing code p1128

Throttle Control Motor Lock Malfunction

I start it now and it revs up to 2000 rpm.. I stop it and restart and it does not idle.. It dies and throw code p1128. If I try to start it, the rpm goes up to 2000 and stays there... The cycle just continues...
 
Trunk Monkey said:
Try unhooking the battery cable and letting the ECU reset.
Click to expand...

Tried that. It did not help at all :-(
 
I recently two weeks ago had my TPS and APPS sensors replaced. I wonder if this has anything to do with it?
 
It might be futile but try disconnecting the TMC connector (on the front right hand facing the engine of the throttle body) and reconnecting. While its disconnected check for any corrosion on both sides of the connector.

First layer of inspection for the TMC:
Turn the ignition switch ON.
When turning the accelerator pedal position sensor lever check the running sound of the Throttle Motor. There shouldn't be any "friction sound".

If you have an ohmmeter you can, per the FSM, check the resistance of the motor:

Terminal 1 (M+) and 2 (M-). Motor resistance: .3-100 ohm at 68 degrees F (20C).

Motor Clutch Resistance:

Terminal 3 (CL-) and 4 (CL+): 4.2-5.2ohm at 68F

If either of your measurements are out of range you'll need a new TMC.
 
Are you referring to disconnecting this plug?
image-2266900938.webp
 
Wow, that fixed it! Why would disconnecting that and reconnecting it make a difference! I really appreciate the help!
 
Not sure other than maybe a little dust or corrosion on the contact points of the terminals. If you have the special electrical contact cleaner and lube (kinda pricy but it works) I'd give both sides of the connector a little spritze/spray. But don't use regular spray lube...make sure you use the special electrical contact cleaner and lube! BTW: I use this same electrical cleaner-lube spray on all the connectors including the MAS connector...

Hopefully its a permanent fix for you.
 
Ok, thanks. I asked my mechanic what he thinks and he said unplugging it and plugging it back in causes the Apps or TPS to recalibrate?
 
I went to start my truck this am and it's back to its old stalling tricks. It won't idle. So I was able to drive it in limp mode over to my local mechanic who will look into it on Monday....
 
SanDiegoCruiser said:
I went to start my truck this am and it's back to its old stalling tricks. It won't idle. So I was able to drive it in limp mode over to my local mechanic who will look into it on Monday....
Click to expand...

What place do you use, if you don't mind me asking?
 
The Truck Shop on Miramar Rd. James takes good care of us 100 Series owners!
 
Yep, it was cleaned two weeks ago when the APPS and TPS was installed.
 
Yep, it was cleaned two weeks ago when the APPS and TPS was installe.
 
Looks like I have a bad throttle control motor. Special order part so it will take a couple of days to fix this issue. This puts me right up against the Mojave Rd Trip date.. Hopefully this fixes the problem since breaking down out in the Mojave Desert is no fun!
 
I experienced the same thing when I changed my battery. It gradually re-learned how to idle and over the course of a few short trips it fixed itself. Note that, at first, it was so bad I had to gas it at stop signs/lights to keep it running. I think the computer had to re-learn or re-calibrate.

I suspect that yours is doing something similar. You may want to drive it a bit before you spend $$ at the shop.
 
Did yours produce p1128 cel?
 
I don't recall if it threw the CEL and, if it did, I didn't check the code. Sorry for the lack of information. You may just want to try a couple of trips while you're waiting for the part.
 
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