Engine/Transmission (1998.5 - 2002) Ecm Replaced

[propuller]

My truck was running bad & the engine light came on so i took the truck to the dealer & they pulled the codes & said i needed a new ecm & it was covered under warranty. well i got my truck back today & it runs good except when i put it gear the engine starts to surge & the tach jumps up & down. This will stop if i tap the throttle or if i put it back in neutral & tap the throttle. If i do nothing the engine continues to surge & gets worse. Sometimes if the truck is in part & i stab the throttle quick it will rev very quickly then as the rpms come down it will start the surging. The fuel pressure is fine & the truck runs great at wide open throttle. I pulled the codes & they are p1693 dtc detected in the companion module & p0622 alternator field not switching properly. the shop also replaced the alternator under warranty. does anybody have any idea what this could be like maybe the ecu program,throttle position sensor. sorry so long but im trying to be thorough. thanks for any help... . kurt. :{

 

[Agades]

what codes did you have ?????

my dealer screwed up my ecm and star center wont ok a new one

so I had to send mine off to cummins at my own expense

 

[stephen bolger]

What did cummins do to your ecm. My truck does the same thing from dad one. Chrysler will not fix it because it will not repeat when they have the truck. :-{} :-{}

 

[Big White Beast]

Book says.........

That code is an open or short on the generator field. I would assume they mean the alternator and that the output is intermittent.



If they changed it they may have not tightened everything down and the ECM is getting intermittent power or surges.



If this is what killed the last ECM there may be a problem in the wiring from the alternator out that they didn't catch. (Oh what a surprise that would be)



Garrett



EDIT: Not sure how responsive the OEM voltmeter is. Grab a known fast responding meter and check the power coming out. Wiggle wires and see if you get a change.

 

[FCrawford]

I can't remember the codes I had but I had a problem that seemed liked the acceleralator was hanging up and it turned out the Injection pump had a timing problem which the dealer was able to duplicate and replace the pump. Other people on the board had similar problems. Don't know if my problem relates to yours at all as I never had any alternator problems?

 

[Marco]

propuller,

Your problem sounds like they've provided your new ECM with the wrong software. Sounds like you have an auto transmission and they've flashed the ECM with a software for a stick.

Thus the surging in gear.

The software for the stick is different. It allows less torque at idle speed. Read it allows less fuel for idle speeds.



The generator field is controlled by the PCM not the ECM.

It's a common problem with the PCM's. I've repaired several of them because they had troubles with the generator field.



Frequently the problems with the PCM/Genrator field are caused by sticking air heather relays.



Marco

 

[DPKetchum]

How many miles have you put on new ecm?It does go through a learn mode. Cold starts/restarts etc. The gas ones usually settle down in a couple of days or 50 miles or less.

 

[LSMITH]

Marco is right on the surging, it is a manual transmission program. It may get better but I doubt it. The injectors and TC are two strikes with a manual program.

 

[propuller]

Thanks for all the help guys im going to write down any info so i can take it to the dealer & hopefully get this fixed. I put about 5 miles on the truck since the new ecm & the surging continues in gear. If i dont hold the brake the truck would take off. Also there is a flat spot in the throttle right off idle. Its like i can push down on the go pedal a little & nothing happens then all of a sudden the rpms jump up & the truck takes off. Other than this the truck seems to run fine. Again thanks for all the info & any other ides you guys have will be checked out... kurt.