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 Descriptors
DTC B3950 02: Left Rear Turn Signal Circuit Short to GroundDTC B3950 05: Left Rear Turn Signal Circuit Open or Short to Voltage
DTC B3951 02: Right Rear Turn Signal Circuit Short to Ground
DTC B3951 05: Right Rear Turn Signal Circuit Open or Short to Voltage
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Hazard Switch Signal | 2 | 2 | 2 | -- |
Left Turn Signal Switch Signal | 1 | 1 | -- | -- |
Right Turn Signal Switch Signal | 1 | 1 | -- | -- |
Right Rear Stop/Turn Signal Lamp Control | B3951 02 | B3951 05 | B3951 05 | -- |
Left Front Turn Signal Lamp Control | B3948 02 | B3948 05 | B3948 05 | -- |
Right Front Turn Signal Lamp Control | B3949 02 | B3949 05 | B3949 05 | -- |
Left Rear Stop/Turn Signal Lamp Control | B3950 02 | B3950 05 | B3950 05 | -- |
Left Rear Stop/Turn Lamp Ground | -- | 1 | -- | -- |
Right Rear Stop/Turn Lamp Ground | -- | 1 | -- | -- |
Turn Signal/Multifunction Switch Ground | -- | 1 | -- | -- |
Turn Signal Lamp - LF Ground | -- | 1 | -- | -- |
Turn Signal Lamp - RF Ground | -- | 1 | -- | -- |
1. Turn Signal Lamps and/or Indicators Malfunction 2. Hazard Lamps Malfunction | ||||
Circuit/System Description
Ground is applied at all times at G300 to the turn signal/multifunction switch. The turn signal lamps may only be activated with the ignition switch in the ON or START position. 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 pulsating voltage to the front and rear turn signal lamps through there respective voltage supply circuits. Ground for the left front turn signal lamp is supplied at G101. Ground for the right front turn signal lamp is supplied at G102. Ground for the left rear turn signal lamp is supplied at G400. Ground for the right rear turn signal lamp is supplied at G402.
Conditions for Running the DTC
Battery voltage must be between 9-16 volts.
Conditions for Setting the DTC
B3950 02
This DTC will set when the BCM detects a short to ground in the LR turn signal voltage supply circuit.
B3950 05
This DTC will set when the BCM detects a short to voltage or an open/high resistance in the LR turn signal voltage supply circuit.
B3951 02
This DTC will set when the BCM detects a short to ground in the RR turn signal voltage supply circuit.
B3951 05
This DTC will set when the BCM detects a short to voltage or an open/high resistance in the RR turn signal voltage supply circuit.
Actions Taken When the DTC Sets
B3950 02
When this DTC is present, the LR turn signal lamp will not operate.
B3950 05
When this DTC is present, the LR turn signal lamp will be ON at all times for a short to voltage condition. For an open condition, the LR turn signal lamp will be inoperative.
B3951 02
When this DTC is present, the RR turn signal lamp will not operate.
B3951 05
When this DTC is present, the RR turn signal lamp will be ON at all times for a short to voltage condition. For an open condition, the RR turn signal lamp will be inoperative.
Conditions for Clearing the DTC
| • | The condition responsible for setting the DTC no longer exists. |
| • | A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred. |
Diagnostic Aids
B3950 05
Check the LR turn signal bulb. If the bulb is open, this DTC will set as current only.
B3951 05
Check the RR turn signal bulb. If the bulb is open, this DTC will set as current only.
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 Testing
- Ignition OFF, disconnect the harness connector at the appropriate turn signal lamp.
- Ignition OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit terminal and ground.
- Connect a test lamp between the control circuit terminal and ground.
- Command the appropriate Turn Signal Lamp ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
- If all circuits test normal, test or replace the appropriate turn signal lamp assembly.
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| ⇒ | If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM. |
| ⇒ | If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
