DTC B3938
Diagnostic Instructions
DTC Descriptor
| DTC B3938 02: Fuel Door Actuator Lock Circuit
Short to Ground |
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
Control
|
B3938 02
|
1
|
1
|
-
|
1. Fuel Filler Door Release Inoperative
|
|
| |
Circuit/System Description
The locking and unlocking of the fuel door is a function of the
power door lock system. The fuel door release actuator is supplied
by the door lock signal circuit and the driver door unlock signal
circuit which is switched through the fuel door relay. The fuel
door relay coil is controlled by the body control module (BCM).
When the vehicles doors are unlocked, the body control module (BCM)
will respond by applying voltage to the fuel door relay coil
control circuit. This energizes the coil causing the switch
contacts to close. With the switch contacts closed, the driver door
unlock circuit supplies B+ or ground to the fuel door release
actuator , unlocking the fuel door.
Conditions for Running the DTC
The system voltage is 9-18 V.
Conditions for Setting the DTC
The BCM detects a short to ground on the fuel filler door relay
control circuit.
Action Taken When the DTC Sets
The remote fuel filler door will be inoperative.
Conditions for Clearing the DTC
| • |
This DTC will be current for
as long as the fault is present. |
| • |
When the fault is no longer
present, the DTC will be a history DTC. |
| • |
A history DTC will clear after
50 ignition cycles. |
Reference Information
Schematic Reference
Release Systems Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Fuel Fill Door Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
| 1. |
Command the door latches to
LOCK and UNLOCK with a scan tool, each interior door lock knob
should move between LOCK and UNLOCK |
| 2. |
Command the door latches to
LOCK and UNLOCK with a scan tool, the fuel door unlatch actuator
should LOCK and UNLOCK while changing between the commanded
states |
Circuit/System Testing
| 1. |
Ignition OFF, disconnect the
X2 harness connector at the X50A fuse block - underhood.
|
| 2. |
Connect a test lamp between
the control circuit terminal 36 and ground. |
| 3. |
Command the door latches to
LOCK with a scan tool, the test lamp should briefly illuminate
while commanding the LOCK state. |
| ⇒ |
If the test lamp is always ON, test the control
circuit for a short to voltage. If the circuit tests normal,
replace the K9 body control module. |
| ⇒ |
If the test lamp is always OFF, test the control
circuit for a short to ground or open/high resistance. If the
circuit tests normal, replace the K9 body control module. |
| 4. |
If all circuits test normal,
test or replace the X50A fuse block - underhood . |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
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