Engine/Transmission (1998.5 - 2002) Do I have A bad ECM?

[RickM]

Here's the scoop 99 3500 quad cab auto 118000 miles on it eng all stock . Have a DDR fuel pump mounted on the frame by the tank and fuel pres gauge . The truck hasn't given me any problems here's what happen drove it 100 miles one day no prob. drove the next day 100 miles came home let it idle down then it started to idle funny like on 3 cyl then died I restarted it ran funny checked the gauges no tach reading I could hear the fuel pump running deferent then it died now no start. bump the starter to get the fuel pump to run nothing. Now this is what I did so far new not rebuilt alt about month a go just because 14 years old and 100000 miles just wanted a new one put my backup fuel pump on installed new battery's it was time check all grounds still no start and fuel pump not running. Ok check the service man. for no start . Man reads check ECM for power here's my question have 12.6 volts at the battery's have 12.5 volts at the ECM have only 8.5 volts at the fuel pump. did note that the wait to start light was blinking when I would try to start now it don't come on at all. The gauges all look like there working the other idiot lights come on. Checked all fuse and relays . So did I miss anything before I get a ECM and no taking truck to the dealer not a option I have all ways fixed my owen trucks.

Thanks Rick

 

[rkressg]

Do you have any codes?
I seem to remember a P0602 being the dead ECM code.
I had mine rebuilt by a company in Tampa, not too expensive.

 

[RickM]

Funny thing I have no codes even tried two deferent code readers. That was before I changed the Batterys.


Rick

 

[Road Dog]

One of the stupid things in the design is the lift pump is powered directly from the ECM (no relay or fuse). It should really go through a relay and fuse. If the ECM pump circuit is hooped then a separate manual circuit is the cheapest route.

The engine should still run without a lift pump but it's hard on the VP-44. You can bypass the ECM to see if the engine is ok.

Blue Chip Diesel VP-44 Diagnostics

 

[Ozymandias]

Funny thing I have no codes even tried two deferent code readers. That was before I changed the Batterys.


Rick

That doesn't mean there are no codes at all.
Those cheap code reader only pull the open OBD Codes - not the safe Chrysler Codes. And also not all Codes switch the CEL on, only emissions related codes switch always the CEL.
A dead ECM so is not in the open OBD nor does it switch the CEL.