Conditions for Running the DTC

WARNING: This page is about a different car, the 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

The engine is operating.
The engine speed is between 480-5000 RPM.
The ignition 1 voltage is between 10.5-18 volts.
DTCs P0351, P0352, P0353, P0354, P0355, and P0356 run continuously once the above conditions are met.