B3948

DTC B3948

Circuit Description

Ground is applied by the turn signal switch. When the turn signal switch is placed in the turn left position, ground is applied to the body control module (BCM) through the left turn signal switch circuit. The BCM then applies a pulsating voltage to the LF and LR turn signal lamps through the LF and LR turn signal lamp supply voltage circuits.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B3948 Left Front Turn Signal Circuit

Conditions for Running the DTC

The battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

A short to ground or an open in the LF turn signal lamp supply voltage circuit is present for longer then 0.1 seconds.

Action Taken When the DTC Sets

The left front turn signal lamp does not work.

Conditions for Clearing the DTC

* The DTC will clear on current status after the condition for setting the fault is corrected.
* Will set a history code which will clear after 100 consecutive ignition cycles without a fault present.
* History and current DTCs can be cleared using a scan tool.

Diagnostic Aids

* Check the LF turn lamp bulb. If the bulb is open, DTC B3948 will be set.
* If the DTC is a history DTC, the fault may be interment. refer to Testing for Intermittent Conditions and Poor Connections in Diagnostic Aids. Component Tests and General Diagnostics
* An interment short to ground or an open in the following locations may cause an intermittent malfunction to occur:

- The BCM
- The underhood electrical center
- The left front turn signal lamp supply voltage circuit

Test

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