DTC B3948 or B3949
Diagnostic Instructions
DTC Descriptors
| DTC B3948 02: Left Front Turn Signal Circuit
Short to Ground |
| DTC B3948 04: Left Front Turn Signal Circuit
Open |
| DTC B3949 02: Right Front Turn Signal Circuit
Short to Ground |
| DTC B3949 04: Right Front Turn Signal Circuit
Open |
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
Left Front Turn Signal
|
B3948 02
|
B3948 04
|
1
|
-
|
Right Front Turn Signal
|
B3949 02
|
B3949 04
|
1
|
-
|
1. Turn signal lamp inoperative
|
|
| |
Circuit/System Description
Ground is applied at all times to the turn signal/multifunction
switch. When the turn signal/multifunction switch is placed in
either the turn right or turn left position, ground is applied to
the body control module (BCM) through either the right turn or left
turn signal switch signal circuit. The BCM then applies a voltage
to the front/side and rear turn signal lamps through their
respective voltage supply circuits.
Conditions for Running the DTC
B3948 02, B3948 04, B3949 02 and B3949 04
The appropriate turn signal is active.
Conditions for Setting the DTC
B3948 02 and B3949 02
The BCM detects a short to ground on the control circuit.
B3948 04 and B3949 04
The BCM detects an open control circuit.
Action Taken When the DTC Sets
The appropriate turn signal lamp is inoperative.
Conditions for Clearing the DTC
The condition for setting the DTC is no longer present.
Reference Information
Schematic Reference
Exterior Lights Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Exterior Lighting Systems Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Ignition ON, perform the Left Front Turn Signal Lamp test. The
left front turn signal lamp and turn signal repeater light should
be ON/OFF.
Ignition ON, perform the Right Front Turn Signal Lamp test. The
right front turn signal lamp and turn signal repeater light should
be ON/OFF.
Circuit/System Testing
| 1. |
Ignition OFF, disconnect the
harness connector at the appropriate turn signal lamp. |
| 2. |
Disconnect the negative
terminal of the C1 Battery. |
| 3. |
Test for less than 5 Ω
between the appropriate turn signal lamp ground circuit harness
connector listed below and ground. |
| |
• |
E4RF Turn Signal Lamp - Right
Front ground circuit harness connector terminal B |
| |
• |
E4Z Turn Signal Repeater Lamp
- Right ground circuit harness connector terminal 1 |
| |
• |
E4LF Turn Signal Lamp - Left
Front ground circuit harness connector terminal B |
| |
• |
E4Y Turn Signal Repeater Lamp
- Left ground circuit harness connector terminal 1 |
| ⇒ |
If greater than the specified value, test the
ground circuit for an open/high resistance. |
| 4. |
Reconnect the negative
terminal of the C1 Battery. |
| 5. |
Connect a test lamp between
the appropriate turn signal lamp control circuit harness connector
listed below and ground. |
| |
• |
E4RF Turn Signal Lamp - Right
Front circuit harness connector terminal A |
| |
• |
E4Z Turn Signal Repeater Lamp
- Right circuit harness connector terminal 2 |
| |
• |
E4LF Turn Signal Lamp - Left
Front circuit harness connector terminal A |
| |
• |
E4Y Turn Signal Repeater Lamp
- Left circuit harness connector terminal 2 |
| 6. |
Command the appropriate Turn
Signal Lamp test ON and OFF with a scan tool. The test lamp should
turn ON and OFF when changing between the commanded states.
|
| ⇒ |
If the test lamp is always ON, test the Signal
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 Signal
circuit for a short to ground or an open/high resistance. If the
circuits test normal, replace the K9 Body Control Module. |
| 7. |
If all the circuits test
normal, replace the appropriate turn signal lamp. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|
