DTC B3950 or B3951 Wagon
Diagnostic Instructions
- Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
- Review Strategy Based Diagnosis for an overview of the diagnostic approach.
- Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC B3950 01: Left Rear Turn Signal Circuit Short to BatteryDTC B3950 02: Left Rear Turn Signal Circuit Short to Ground
DTC B3950 04: Left Rear Turn Signal Circuit Open
DTC B3951 01: Right Rear Turn Signal Circuit Short to Battery
DTC B3951 02: Right Rear Turn Signal Circuit Short to Ground
DTC B3951 04: Right Rear Turn Signal Circuit Open
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Left Rear Turn Signal | B3950 02 | B3950 04 | B3950 01 | -- |
Right Rear Turn Signal | B3951 02 | B3951 04 | B3951 01 | -- |
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 right turn or left turn signal switch signal circuit to the body control module (BCM) and the trailing lighting converter. The BCM and the trailing lighting converter then applies a voltage to the rear turn signal lamps through their respective voltage supply circuits.
Conditions for Running the DTC
B3950 01 and B3951 01
The appropriate turn signal is inactive
B3950 02, B3950 04, B3951 02 or B3951 04
The appropriate turn signal is active
Conditions for Setting the DTC
B3950 01 or B3951 01
The control module detects a short to voltage on the control circuit.
B3950 02 or B3951 02
The control module detects a short to ground on the control circuit.
B3950 04 or B3951 04
The control module detects an open control circuit.
Conditions for Clearing the DTC
The condition for setting the DTC is no longer present.
Reference Information
Schematic Reference
Connector End View Reference
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 appropriate Rear Turn Signal / Hazard Lamp Command test. The appropriate rear turn signal / hazard lamp should be ON / OFF
Circuit/System Testing
- Ignition OFF, disconnect the appropriate harness connector at the tail lamp listed below:
- Test for less than 5 Ω between the appropriate turn signal lamp ground circuit harness connector listed below and ground.
- Connect a test lamp between the appropriate turn signal lamp control circuit harness connector listed below and ground.
- 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 all the circuits test normal, replace the appropriate tail lamp / liftgate tail lamp.
| • | E42L Tail lamp left |
| • | E42R Tail lamp right |
| • | E43L Liftgate Tail lamp left |
| • | E43R Liftgate Tail lamp right |
| • | E42L Tail lamp left harness connector terminal D |
| • | E42R Tail lamp right harness connector terminal E |
| • | E43L Liftgate Tail lamp left harness connector terminal B |
| • | E43R Liftgate Tail lamp right harness connector terminal E |
| ⇒ | If greater than the specified value, test the ground circuit for an open/high resistance. |
| • | E42L Tail lamp left harness connector terminal C |
| • | E42R Tail lamp right harness connector terminal C |
| • | E43L Liftgate Tail lamp left harness connector terminal F |
| • | E43R Liftgate Tail lamp right harness connector terminal A |
| ⇒ | If the test lamp is always ON, test the Signal circuit for a short to voltage. If the circuit tests normal, replace the appropriate 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 appropriate control module. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM or trailer lighting converter replacement, setup and programming |
DTC B3950 or B3951 Sedan Hatchback
Diagnostic Instructions
- Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
- Review Strategy Based Diagnosis for an overview of the diagnostic approach.
- Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC B3950 01: Left Rear Turn Signal Circuit Short to BatteryDTC B3950 02: Left Rear Turn Signal Circuit Short to Ground
DTC B3950 04: Left Rear Turn Signal Circuit Open
DTC B3951 01: Right Rear Turn Signal Circuit Short to Battery
DTC B3951 02: Right Rear Turn Signal Circuit Short to Ground
DTC B3951 04: Right Rear Turn Signal Circuit Open
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Left Rear Turn Signal | B3950 02 | B3950 04 | B3950 01 | -- |
Right Rear Turn Signal | B3951 02 | B3951 04 | B3951 01 | -- |
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
B3950 01 and B3951 01
The appropriate turn signal is inactive
B3950 02, B3950 04, B3951 02 or B3951 04
The appropriate turn signal is active
Conditions for Setting the DTC
B3950 01 or B3951 01
The BCM detects a short to voltage on the control circuit.
B3950 02 or B3951 02
The BCM detects a short to ground on the control circuit.
B3950 04 or B3951 04
The BCM detects an open control circuit.
Conditions for Clearing the DTC
The condition for setting the DTC is no longer present.
Reference Information
Schematic Reference
Connector End View Reference
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 appropriate Rear Turn Signal / Hazard Lamp Command test. The appropriate rear turn signal / hazard lamp should be ON / OFF
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the appropriate turn signal lamp.
- Test for less than 5 Ω between the appropriate turn signal lamp ground circuit harness connector listed below and ground.
- Connect a test lamp between the appropriate turn signal lamp control circuit harness connector listed below and ground.
- 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 all the circuits test normal, replace the appropriate turn signal lamp.
| • | E106RH Right Rear Turn Signal Lamp ground circuit harness connector terminal A |
| • | E106LH Left Rear Turn Signal Lamp ground circuit harness connector terminal F |
| ⇒ | If greater than the specified value, test the ground circuit for an open / high resistance. |
| • | E106RH Right Rear Turn Signal Lamp circuit harness connector terminal D |
| • | E106LH Left Rear Turn Signal Lamp circuit harness connector terminal F |
| ⇒ | 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 (BCM). |
| ⇒ | 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 (BCM). |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup and programming |
