Conditions for Setting the DTC

WARNING: This page is about a different car, the 2017 GMC Acadia. However, it is still accessible from the selected car via links, so may be relevant.

DTC B3948 01 and B3948 04

The BCM detects a short to voltage or an open/high resistance in the left front turn signal control circuit.
The BCM detects a short to ground or an open/high resistance in the F13DA (BCM 7) fuse B+ circuit.

DTC B3948 02

The BCM detects a short to ground in the left front turn signal control circuit.

DTC B3949 01 and B3949 04

The BCM detects a short to voltage or an open/high resistance in the right front turn signal control circuit.
The BCM detects a short to ground or an open/high resistance in the F7DA (BCM 3) fuse B+ circuit.

DTC B3949 02

The BCM detects a short to ground in the right front turn signal control circuit.