B2403

DTC B2403 Fog Lamp Switch Circuit:

DTC B2403 Fog Lamp Switch Circuit (Part 1 Of 2):

DTC B2403 Fog Lamp Switch Circuit (Part 2 Of 2):

CIRCUIT DESCRIPTION
The Body Control Module (BCM) enables (but may not activate) the fog lamps whenever the ignition switch is in RUN position. The BCM provides the fog lamp relay coil with a ground (through the fog lamp switch contacts) when the ignition switch is in the RUN position.

CONDITIONS FOR SETTING THE DTC
^ The BCM detects battery voltage in circuit 192 when in the RUN mode.
^ The BCM detects battery voltage in circuit 1317 when in the RUN mode and the fog lamp switch is on.

ACTION TAKEN WHEN THE DTC SET
^ Stores a DTC B2403 in the BCM memory.
^ The BCM turns off its output to the fog lamps relay.
^ No driver warning message will be displayed for this

CONDITIONS FOR CLEARING THE DTC
^ Battery voltage is no longer detected by the BCM in circuit 192 when the ignition switch is cycled from the OFF position to the RUN position.
^ A history DTC will clear after 100 consecutive ignition cycles if the condition for the fault is no longer present.
^ Ignition cycle is needed to clear the current DTC.
^ Using a scan tool.

DIAGNOSTIC AIDS
^ The following conditions may cause an intermittent malfunction to occur:
- An intermittent short to voltage in circuit 192 or 1317.
^ If the DTC is a history DTC, the problem may be intermittent. Try performing the tests shown while wiggling wiring and connectors, this can often cause the malfunction to appear.
^ DTC P1626 will set in the Powertrain Control Module (PCM) when the ignition switch is in the RUN position with the BCM disconnected.

TEST DESCRIPTION
Numbers below refer to the step numbers on the diagnostic table.
1. Always perform the BCM Diagnostic System Check before attempting to diagnose a DTC B2403.
2. Checks for a short to voltage in circuit 192.
3. Determines if the short to voltage is located in circuit 192 or in the BCM.
4. Checks for a short to voltage in circuit 1317.
8. Determines if the short to voltage is located in circuit 1317 or in the fog lamp relay.
9. Checks for a short to voltage in the fog lamp switch.
10. Determines whether the short to voltage is in the Underhood (UH) electrical center or in circuit 1317.