diesel truck, limp mode question
do our diesel trucks have a limp mode? I have a 2005 dodge diesel we were rolling along fine the other day around a bypass in Louisville, KY. I notice a 18 wheeler with its flasher lights blin...
Forum Discussion
The are many things that can cause the '05 to go to limp mode.
Engine:
Overboost: If I remember correctly it will limit rail pressure to 20kpsi, and something else.
If an injector harness shorts to ground, the computer will drop those 3 cylinders (the front 3 or the rear 3, whichever half of the engine had the problem).
There are many more.
Transmission:
Over temperature, 265* or something, the torque converter will lock and default to 2nd gear.
Loss of overdrive relay will get you stuck in 3rd, but you can swap out the heater mirror relay to prove the relay itself is at fault.
Loss of speed sensor will default you to 2nd, since the truck doesn't know how fast it is going.
A lot of the time, a key cycle will get you rolling again if you are in the middle of nowhere. But checking code(s) are ideal.
Engine:
Overboost: If I remember correctly it will limit rail pressure to 20kpsi, and something else.
If an injector harness shorts to ground, the computer will drop those 3 cylinders (the front 3 or the rear 3, whichever half of the engine had the problem).
There are many more.
Transmission:
Over temperature, 265* or something, the torque converter will lock and default to 2nd gear.
Loss of overdrive relay will get you stuck in 3rd, but you can swap out the heater mirror relay to prove the relay itself is at fault.
Loss of speed sensor will default you to 2nd, since the truck doesn't know how fast it is going.
A lot of the time, a key cycle will get you rolling again if you are in the middle of nowhere. But checking code(s) are ideal.
