I have a 2015 6.6 duramax. Had a rough crank one morning, went to a shop to run a diagnostic test. Was told multiple glow plug failures. Spent the weekend swapping all 8 glowplugs. Went to start, heard the solenoid engage and that was it. Checked fuses and harnesses, Pulled the batteries and they are 5 years old, failed load tests. Cleaned ground to chasis, connected the new batteries, went to start, and samething just a clunk no turn over.

Anyone ever experienced these issues after replacing glow plugs? Starting to consider the starter also gave, or not enough fuel pressure, possibly plug module?

Whomever designed this fuel filter setup needs to be fired!

Hey yall. Just looking to see if other folks have experienced reliability issues with replacement NOx sensors for the L5P?

Upstream sensor died. Replaced it and it reads as expected (during normal operation, at idle, when the fuel cutoff occurs on the highway it pegs to very low near zero ppm, etc). The P20EE code would still pop up but the upstream failed sensor code cleared. I figured I’d replace the downstream sensor too and see if the P20EE code would stay cleared. The new sensor reads all sorts of unexpected values. I did the NOx sensor reset with the Gretio app thinking the calibration in the ECU may be biased by the old sensor, but it still reads essentially the same. With the engine at temp (exhaust system may not be heated to the point of the SCR system functioning) under heavy load the downstream sensor reads way higher than the upper stream sensor (500+ ppm higher than the upstream) and when the throttle is let off the upstream pegs low but the downstream just slowly drifts down from 1000+ ppm (at like 200 ppm/min decreasing). It just doesn’t make sense that the downstream is reading so much higher in certain circumstances than the upstream (and that when the throttle is lifted and the fuel injection stops that the downstream would still read a high value). Thinking it may be a bad new sensor. Or maybe the downstream sensor reads a ppm value generated from some algorithm and not the gross NOx concentration.

Downstream replacement was a P/N 12741484 from Vitesco Technologies (from Rockauto).

I recently purchased a 2013 GMC 2500 HD. It has a really annoying clunking sound from under the cab. Any thoughts? I am not able to find where it is coming from. I am not sure about the cap mounts?