P0542 OBD2 Fault Code Persisting on 2017 Dodge RAM 3500 (Solved with Exhaust Temperature Sensor Replacement)
I own a 2017 Dodge RAM 3500 with 42,000 miles and have been experiencing the P0542 OBD2 diagnostic code for the past five years. The issue typically appears when outside temperatures exceed 80°F, especially after prolonged highway driving or extended idling at rest stops. The check engine light activates intermittently—sometimes staying off for hours before reappearing—and the truck runs smoothly both before and after the warning light comes on. I've attempted multiple solutions: four replacements of the idle control relay, two heater core changes, and a replacement of the intake air temperature/pressure sensor (as recommended by Cummins). Despite these efforts, the P0542 code persists. The dealership has confirmed that wiring checks were completed but remains unable to identify or resolve the root cause. Online forums suggest possible issues with the exhaust temperature sensor or the Powertrain Control Module (PCM)/ECM, but I'm seeking firsthand experiences from other owners of the 2017 RAM 3500 who have encountered this exact issue. Any verified solutions, troubleshooting steps, or known fixes would be greatly appreciated before I consider further costly repairs. Note: The P0542 code specifically relates to an abnormal exhaust gas temperature reading, which may point toward a faulty sensor or signal interference in the thermal management system.
A detailed article on P0542 is available at https://www.obd-codes.com/p054-2 - it provides general information about this code. However, in practice, dealerships should be able to diagnose and resolve such issues. If one dealership is unable to help, consider visiting a different service center with experience in diesel trucks or specialized diagnostics for the 2017 RAM 3500. A known fix for P0542 on this model involves replacing the exhaust temperature sensor, which has been reported to resolve the issue in many cases.