Communication DTCs Set on 3.0L Duramax Diesel Engine

Several communication DTCs may be set on some 2022 Silverado 1500, Tahoe, Suburban, Sierra 1500, Yukon and Escalade models equipped with the 3.0L Duramax diesel engine (RPO LM2). Along with an illuminated Check Engine MIL, DTCs U1345 (Engine Control Module LIN Bus 1), U02A9 (Loss of Communication with Charge Air Cooler Pump), U0284 (Lost Communication with Active Grill Air Shutter Actuator 1) and U0285 (Lost Communication with Active Grill Air Shutter Actuator 2) may be set in the Engine Control Module (ECM).

Based on the specific DTCs set in the ECM, there are several possible repairs to perform.

Electrical Connector

DTCs U02A9 and U1345 may be caused by an unsealed pump electrical connector allowing water leakage into the (M10) connector. Moisture introduced into the charge air cooler pump electrical connector may lead to communication failure.

Check the CAC Pump connector sealing. (Fig. 1) Be sure to look for any corrosion at the pump due to possible water leakage.

 

Fig 1

 

Wiring Harness to In-line Connector

DTCs U1345, U0284 and U0285 may be caused by the engine wiring harness-to-active grille air shutter actuator in-line connector. The connector may not be properly connected, not properly held in place by the rear clip, or may be grounded on the radiator. Check the connection of circuit 4621 for any these possible concerns. (Fig. 2)

 

Fig. 2

 

Pinched Wiring

DTCs U1345 and U0284 may be caused by the active grill air shutter wiring being pinched at the radiator support.

Check the routing of the active grill air shutter wiring, especially at the lower-left corner of the shutter, to determine if there are any possible damaged points in the wiring. (Fig. 3) Repair the wiring as needed.

 

Fig. 3

 

For additional information, refer to Bulletin #22-NA-252.

– Thanks to Larry Yaw