Engine/Transmission (1998.5 - 2002) Need Help - Truck stats out in limp mode

[DennyDay]

My 01 automatic (box stock) starts out in the AM in limp mode. When it warms up it is fine and runs very well. Also if it sits at work all day same thing happens.



Anybody got any suggestions?



As an aside, Cummins just replace the lift pump and I replaced the APPS, both for sa slightly different problem.



Any help would be appreciated.



Denny

 

[ToolManTimTaylor]

How do youknow its in limp? Cycle the key on / off three times WITHOUT starting the engine leaving the key in the ON position on the final cycle and write down the codes (If any ) that appear in the odometer display and report back. What are your pressures (Fuel Boost egt) ? Is it starting out in seccond gear making it FEEL like a limp / low power mode?

 

[DennyDay]

Problem

Tim - - - The code on the odometer reads P PCU. (mileage 79,000) I don't know the fuel pressure but there has been a new lift pump installed in the last two weeks at Cummins, and I purchased and installed an APPS. I have a Jannetty pump as a pusher down on the frame. I'm wondering if a sensor is acting up because it runs so good after it warms up. As far a second gear start out, I don't think so, because ther is no rise in EGT or boost, I've got it scheduled in the transmission shop for a routine change of fluid, filter and adjustment.

Unfortunately I'm also beginning to think about the injector pump (Hate that thought) but I need the truck for work related travel. The rest of the problem is that I don't know of a trustworthy dealer here in Ohio, that has a diesel tech.



If you have any ideas or have had this problem, sure would be glad to hear about it.



Denny

 

[ToolManTimTaylor]

P Pcu? Did the code cycle thru ALL the modes then return back to milage display? It should have read something like this below if no codes were in the P C U



"P-PCU" "P-DONE" = No codes between Pcu Start And Pcu Finish





"P-ECU" "P-DONE" = No Codes between Ecu Start And Ecu Finish

 

[DennyDay]

Codes

Tim - - Waited the readout out and it said P PCU then P 1693. Does this help?



Denny

 

[ToolManTimTaylor]

Yes a 1693 is a "companion" code to something else that is set within the ECM (Being it went P-PCU allready) so a "Hard code may still exist and may require the use of a scantool (Autozone FREE READS!!). I was looking for a 216 (INJECTION PUMP TIMING FAILURE) , 217 (A limp code usually from overheat) , Even a Cam sensor 341.



Has the Tach been erratic lately?? (Erratic being a 1000 rpm swing or not at all)

 

[DennyDay]

Onward

Tim - No the tach hasn't been eratic, last night I did the following: Pulled the IAT sensor to clean and it was spotless, but I put dielectric on the contacts, also pulled MAP and did same. Pulled plug on injector pump and greased also. Then test ran truck and it was fine. This AM started out and had the same problem as I started with, but no where as bad, it would accelerate slowly, and this time felt like trans stayed in second gear. I'm going to change the IAT sensor and see what happens, and the transmission is set to be serviced Thursday. If I've offered any clues, please let me know.



Thanks,

Denny

 

[Lsfarm]

Try this

In the morning if it feels like it is in 2nd gear come to a stop and manually put it in first, if it launches like it should then it is starting in 2nd when cold, and needs the Governor Solenoid and Governor sensor changed. Do this test before you take it in for the trans ATF change. It is very little extra labor to change the sensor and solenoid while the pan is down. The parts are around $180 from the dealer.



If when you put into 1st manually it locks up [two gears at once] DON'T floor it to try to get it to move!! The Trans may self destruct. Try just shutting it off and starting again then try it in drive.



Don't let the trans shop tell you you need a new trans because of this!! It usually is just the sensor and solenoid.



If it runs the same, then you have something going on with cold engine fueling causing the poor performance.



If you are in Northwest OH, send me a PM, maybe I can drive it or help.



Greg L

 

[DennyDay]

Limp Mode

Greg - Sounds like a solution, when I shift to neutral it responds normally, will try manually shifting to first.



Thanks,

Denny

 

[pro99]

Gov sensor?

It may not take off in first gear even if you manually put in manual first and it still can be the valve body..... Done too many like this... .

 

[DennyDay]

Might Be!

Greg and Tim



When I left work this PM it had cooled down enough to act like it has in morning. I manually pulled the transmission into first and altho sluggish it did immediatly down shift and took off. This may be the answer. I'm scheduled in the transmission shop Thursday AM for an oil and filter change. Called shop today so they could have parts on hand. Will let you know outcome.



Thanks for your help and suggestions - - - TDR at its best ! ! !



Denny

 

[DennyDay]

Peace in the valley tonight!

Tim, Greg and pro68



Truck runs like a new one - - changed out both transmission the sensor and solenoid when the trans was serviced, and now we are right where we need to be. I'm going to change out the MAP and AIT sensoes next week as a time to do it project.



As a result I have also identified a top independent transmission shop in Canton, Ohio.



Any body needs a trans shop please PM me.



Again, thanks for your help and ideas.



Denny