Throwing the following codes: PCU P1693, ECU P0237, P0112
My mechanic has checked the wiring, the connectors, the grounds and both sensors in question. He's 99% certain it's an ECU failure but if anyone has any insight to share, it would be welcome.
Apparently, this ECU is unique to the '01-'02 6 speed HO trucks and therefore hard to find.

Any help would be appreciated.
Randy.

 

0237 is boost pressure sensor, 0112 is intake air temp sensor.

do you have an exhaust brake on there? Either way, I've seen the sensors get dirty, and throw bad readings. I have also seen sensors short internally over time, and I've seen bad wires leading to the sensors. These bad wires can appear just fine, but be compromised inside the insulation. Any of these things can cause a limp mode. I'm familiar with ecu failures across many brands, and with the exception of the injector driver side of cat ecms, ive never seen one fail just one or two sensors out of several.

 

I do have an exhaust brake.
Doesn't seem likely that both sensors would fail at the same time. Something in common in the wiring like a ground failing makes more sense to me.
My mechanic says he has checked both of the sensors and the wiring, grounds and connectors.

 

IIRC these 2 sensors share the same +5V supply from the ECM, so if one of them shorts the supply to the ground both will stop working.
I'd start by checking those sensor's wiring for a chafed wire.

 

Quizzed my mechanic a bit this morning. Seems like he was pretty thorough about back probing all the wiring in question. Load tested and resistance checked. cleaned up the grounds etc. Swapped out both of the sensors with known good ones out of his personal truck. If not the ECM itself, he says about the only likely possibility is the block connector on the ECM.

 

Check both your batteries and the alternator for output voltage.....