Diagnostic Aids

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Refer to the following table to determine which fuel injector control circuit is malfunctioning.

DTC P1223, P1226, P1229, P1232, P1235, P1238, P1241, or P1244

DTC	Cylinder
P1223	1
P1226	2
P1229	3
P1232	4
P1235	5
P1238	6
P1241	7
P1244	8