LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 2006 >> Sierra 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1302 (Data Communication System) >> Diagnostic Information and Procedures >> DTC U1821 >> Diagnostic Fault Information

Diagnostic Fault Information

WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performance
B+ U1821* U1821 - -
Ground - U1821* - -
PTLAN + U0074* U1821, 1 U0074* -
PTLAN - U0074* U1821, 1 U0074* -
* Other modules/DTCs may set with this fault.
1. Multiple DTCs including U1821 may set and multiple symptoms including a no start condition may occur.