Conditions For Clearing DTC P1811

WARNING: This page is about a different car, the 2003 Buick Regal and 2003 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.

DTC will clear under the following conditions:

A scan tool can clear the DTC.
The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without a non-emission-related diagnostic fault occurring.
The PCM cancels the DTC default actions when the ignition is OFF long enough to power down the PCM.