Limp mode no trans light

[Cdriscoll773]

Hello,

I am trying to troubleshoot my M1123 that is in limp mode. I tried to pull codes with the jumper wire. The trans light doesn’t come on at all. I tested for power on all of the wires going towards the relay and breaker when the vehicle is in the run position. There was no power on either wire to the breaker. The only wire that had power in the bunch was 291. Can anyone please confirm if this sounds like a relay switch? Or something else?

 

[NDT]

Sounds like some wires are disconnected in the battery box. Check all your connections.

 

[Milcommoguy]

Hello,

I am trying to troubleshoot my M1123 that is in limp mode. I tried to pull codes with the jumper wire. The trans light doesn’t come on at all. I tested for power on all of the wires going towards the relay and breaker when the vehicle is in the run position. There was no power on either wire to the breaker. The only wire that had power in the bunch was 291. Can anyone please confirm if this sounds like a relay switch? Or something else?

Get the schematic diagram and follow along. Be careful and DON'T make the connection if wire are loose to the positive 24 Volt battery / source.

It is a 12 Volt TCM system... with a slave controlled (24 Volt) relay coil feed off the RUN circuit with contacts making the 12 Volt switched feed to TCM. Sounds like you have it figured out... But to clarify and help others...cuz it comes up all the time. (and I know of a few OOPS customers)

The drawings / manual for the first time Steel Soldier >

https://gear-report.com/wp-content/uploads/2017/03/Supplement_7_4L80E-Transmission_Troubleshooting.pdf

My two cents worth for everyone FREE, CAMO