Diagnostic Aids

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

Avoid cycling the ignition unnecessarily while the fuse is open. Turning the ignition ON twice with an open fuse results in a 20-40 minute precharge wait time, during which time precharging will be inhibited. It will be necessary to wait until the scan tool Precharge Wait Time parameter counts down to 0 Seconds before continuing with diagnosis.
DTC P0A95 will only set if the fuse opens while the contactors are closed. If the fuse is already open when the ignition is turned from OFF to ON, the precharge test will fail, and DTC P1A20 will set.
When the high voltage fuse is open the vehicle will not start.
Test for HVIC circuit operation by lifting up on the high voltage manual disconnect lever to disengage the HVIC circuit. Monitor the HVIC source and return current on the scan tool. HVIC return current should read 0 ma when the high voltage manual disconnect lever is lifted.
If this DTC sets when the manual disconnect lever is removed, the HVIC circuit may have a wire to wire short on the HVIC source and return circuits between the X350 and the HV manual disconnect lever connector.
If the HV fuse opens as soon as the high voltage manual disconnect is installed with the ignition OFF and the HV contactor relays are not stuck closed, The problem is internal to the drive motor generator battery assembly.