Diagnostic Aids

WARNING: This page is about a different car, the 2009 GMC Yukon and 2009 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.

A malfunctioning speed sensor could cause DTC P2771 to set.

Verify that the input speed sensor (ISS) and the OSS are functioning properly.
In 3rd gear at approximately 64 km/h (40 mph), command TCC ON. If functioning properly the OSS will track ISS and the engine RPM. If not refer to DTC P0716 for the ISS and DTC P0723 for the OSS.
If the speed sensors pass testing, refer to Testing for Intermittent Conditions and Poor Connections .