Lift Pump not working

[Raven1466]

Need some help on diagnosing a lift pump that isn't turning on, 2010 Cummins ISX CM2250. I've read that there should be a inline fuse, but cannot find it on the connector. I did find a relay close to the ECM and was wondering if the lift pump is connected to this relay before I try and swap it out? I checked the battery box and didn't see any fuses in there also. Thanks in advance.

2011 Kenworth T-660

[Rawze]

are you sure that 2010 engine is a CM2250?
What is the engine ESN#? (the engine sreial number)?

Knowing which model engine you have speaks volumes about how the lift pump works and what relay your looking at.

[Raven1466]

ESN 79428482, I'm pretty sure it's a CM2250. I appreciate your EGR tune up videos, I'm working on that now and have replaced most of the sensors already. I just got this truck so I'm new and learning as I go, thanks for all you do.

[Rawze]

(04-27-2021 )Raven1466 Wrote:  ESN 79428482, I'm pretty sure it's a CM2250. I appreciate your EGR tune up videos, I'm working on that now and have replaced most of the sensors already. I just got this truck so I'm new and learning as I go, thanks for all you do.

yeah, its a CM2250 according to that ser#. - Year 2010, it could have gone either way.... That is why I asked.

All you have to do is make a quickserv.com account and you can get the ecm wiring diagram. That should tell you about any relay or fuses in the wiring harness. - Quickserv is free.

wiring diagram...
https://quickserve.cummins.com/qs3/porta...h/4022234/

[dhirocz]

You said it's a 2011 T660 but a 2010 ISX. Two different engines. I've seen an early 2011 with a cm871 but never a 2010 with a cm2250. You sure you didn't have a valve cover switched out on it or something in the past? Does the s/n on the block (passenger rear behind the oil cooler on a flat pad) match the one on the valve cover?

...rawze got it first. A 2010 with a cm2250 would be kind of a unicorn, wouldn't it? I had a friend of mine with a cm871 in an 11 T660. That's odd.

[Rawze]

(04-25-2021 )Raven1466 Wrote:  Need some help on diagnosing a lift pump that isn't turning on, 2010 Cummins ISX CM2250.
...

2011 Kenworth T-660

Is the truck de-mandated (deleted)?... if so, besides just a wiring issue, it could also be a bad delete file. It is not unusual for bad delete programming to be unstable and do things like not allowing the ecm to fully shut down after the key switch is off... or for ghost problems including the lift pump to stop working due to file corruption, etc.

[RollinCoal]

Use a "computer safe" test light (computer safe has a little pc board and LED lights) unplug the lift pump use the diagram above have the test light in the hot side and turn key on, it should light up for 30 sec.
then swap clip the light on hot side of alt and test the ground
If it all works and lights up replace the pump, those pumps are pretty good but I have had to replace a few, usally on higher mileage trucks

[Raven1466]

(04-27-2021 )dhirocz Wrote:  You said it's a 2011 T660 but a 2010 ISX. Two different engines. I've seen an early 2011 with a cm871 but never a 2010 with a cm2250. You sure you didn't have a valve cover switched out on it or something in the past? Does the s/n on the block (passenger rear behind the oil cooler on a flat pad) match the one on the valve cover?

...rawze got it first. A 2010 with a cm2250 would be kind of a unicorn, wouldn't it? I had a friend of mine with a cm871 in an 11 T660. That's odd.

The truck is a 2011 with a engine model year 2010 ISX CM2250. It has DPF and DEF and is not deleted, I'm in California.

[SquareOne]

If you knew someone with a PowerProbe (or equivalent), you could isolate the pump by unplugging and sending power directly to it in order to check if its still working.