Chased a ghost code on a 6.7 Cummins for 4 hours straight

I had an '15 Ram 2500 come in last Tuesday with a random derate and a P0234 code. Checked the turbo actuator, found a sticky vane, cleaned it all up, and it still limped. Turned out the VGT solenoid was sending wrong voltage but only at operating temp after a 20 minute drive. Has anyone else had a sensor fail that checked good cold but went bad hot?

2 comments

2 Comments

amy_foster561mo ago

Did you check the VGT solenoid wiring harness for chafing near the exhaust?

angelac631mo ago

Gotta push back on that a little, Amy. I’ve chased that harness on a few trucks and never found chafing near the exhaust (maybe it’s a certain year or build?). Usually the issue is the solenoid itself getting cooked by heat soak, not the wires rubbing. I had one where the connector pins were actually corroded from moisture getting in through the boot, not chafing. So I’d check the pins and the solenoid resistance before ripping into the harness, plus look for any melted plastic on the solenoid case itself. Just my two cents from fighting these things in the field.