B2104-IGNITION UNLOCK RUN/START CONTROL CIRCUIT LOW

For a complete wiring diagram Refer to Section 8W.

When Monitored:
With the ignition on.
Set Condition:
The Front Control Module will set this DTC within 500ms if the (F1) fused ignition switch output circuit voltage is less than the expected value.

Possible Causes

(F1) FUSED IGNITION SWITCH OUTPUT CIRCUIT SHORTED TO GROUND

SHIFT LEVER ASSEMBLY (3.7L ONLY)

POWERTRAIN CONTROL MODULE (EXCEPT 3.7L)

INTEGRATED POWER MODULE

FRONT CONTROL MODULE

Theory of Operation

The (F942) Fused Ignition Switch Output circuit supplies the FCM with battery power. The FCM processes the input and sends it out as the (F1) Fused Ignition Switch Output circuit to the Shift Lever assembly (3.7L) or the PCM (except 3.7L).

Diagnostic Test

1.CHECK FOR ACTIVE DTC

Does the scan tool display this DTC as active?

Yes

Go To 2

If the DTC is stored, check for an intermittent condition. Using the wiring diagram/schematic as a guide, visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals.

2.DETERMINE ENGINE SIZE

Is this vehicle equipped with a 3.7L engine?

Yes

Go To 3

Go To 6

3.SHIFT LEVER ASSEMBLY

Does the scan tool display this DTC as active?

Yes

Go To 4

Replace the Shift Lever Assembly in accordance with the service information.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE) .

4.(F1) FUSED IGNITION SWITCH OUTPUT WIRE SHORT TO GROUND

Is the resistance below 1000.0 ohms?

No

Go To 5

Yes

Repair the (F1) Fused Ignition Switch Output circuit for a short to ground.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE)

5.INTEGRATED POWER MODULE SHORTED

Is the resistance below 1000.0 ohms?

Yes

Replace the Integrated Power Module in accordance with service information.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE)

Replace and program the Front Control Module in accordance with the service information.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE)

6.POWERTRAIN CONTROL MODULE

Does the scan tool display this DTC as active?

Yes

Go To 7

Replace the Powertrain Control Module in accordance with the service information.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE) .

7.(F1) FUSED IGNITION SWITCH OUTPUT WIRE SHORT TO GROUND

Is the resistance below 1000.0 ohms?

No

Go To 5

Yes

Repair the (F1) Fused Ignition Switch Output circuit for a short to ground.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE)