AutoCodes – Generic – B3948:02

B3948:02 Code - Left Front Turn Signal Circuit Short to Ground

Quick Answer

Ground is applied at all times to the turn signal/multifunction switch. Common causes include Faulty Left Front Turn Signal Lamp, Left Front Turn Signal Lamp harness is open or shorted, Left Front Turn Signal Lamp circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: B3948:02 indicates Left Front Turn Signal Circuit Short to Ground.
Common causes: Common causes include Faulty Left Front Turn Signal Lamp, Left Front Turn Signal Lamp harness is open or shorted, Left Front Turn Signal Lamp circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 221

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 17, 2023

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B3948:02 Description

Ground is applied at all times to the turn signal/multifunction switch. The turn signal lamps may only be activated with the ignition switch in the ON or START positions. 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 responds to the turn signal switch input by applying a pulsating voltage to the front and rear turn signal lamps through there respective control circuits. When a turn signal request is received by the BCM, a serial data message is sent to the instrument cluster requesting the respective turn signal indicator be pulsed ON and OFF. The Diagnostic Trouble Code (DTC) will be set when the BCM detects a short to ground in the left front turn signal control circuit.

OBDII Code B3948:02 - Left Front Turn Signal Circuit Short to Ground - AutoCodes.com — B3948:02 Code - Left Front Turn Signal Circuit Short to Ground

What does this mean?

What are the Possible Causes of the DTC B3948:02?

Faulty Left Front Turn Signal Lamp
Left Front Turn Signal Lamp harness is open or shorted
Left Front Turn Signal Lamp circuit poor electrical connection
Faulty Body Control Module (BCM)

How to Fix the DTC B3948:02?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B3948:02 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about B3948:02 Code

1. What are the common symptoms of OBDII code B3948:02 (Left Front Turn Signal Circuit Short to Ground)?

- Common symptoms include the left front turn signal not functioning properly, the turn signal indicator flashing rapidly, or a constant illumination of the turn signal.

2. What are some possible causes of OBDII code B3948:02?

- Possible causes include a short to ground in the wiring of the left front turn signal circuit, a faulty turn signal bulb, or a malfunctioning turn signal switch.

3. How can I diagnose the issue related to OBDII code B3948:02?

- You can start by visually inspecting the wiring and connections in the left front turn signal circuit. Check for any exposed or damaged wires, loose connections, or corrosion. Using a multimeter to test for continuity and shorts can also help pinpoint the issue.

4. Can a faulty turn signal bulb trigger OBDII code B3948:02?

- Yes, a faulty turn signal bulb can cause a short to ground in the circuit, triggering the OBDII code B3948:02. It is recommended to inspect and replace the bulb if necessary.

5. How can I repair OBDII code B3948:02 (Left Front Turn Signal Circuit Short to Ground)?

- Repairing this code involves locating the short to ground in the left front turn signal circuit and addressing the root cause, such as fixing damaged wiring, replacing a faulty turn signal bulb, or repairing a malfunctioning turn signal switch.

6. Is it safe to continue driving with OBDII code B3948:02 active?

- It is not recommended to continue driving with this code active, as it can affect the proper operation of the left front turn signal. This can pose a safety hazard for you and other drivers on the road.

7. Will resetting the OBDII code B3948:02 make the issue go away?

- Resetting the code may temporarily turn off the warning light, but the underlying issue causing the code will persist. It is important to diagnose and repair the problem to prevent the code from reoccurring.

8. Can extreme weather conditions contribute to triggering OBDII code B3948:02?

- Yes, extreme weather conditions such as heavy rain or snow can potentially expose wiring to moisture, leading to a short to ground in the left front turn signal circuit and triggering the OBDII code B3948:02.

9. How long does it typically take to repair OBDII code B3948:02?

- The repair time for this code can vary depending on the exact cause of the issue. Simple fixes like replacing a turn signal bulb may take a short time, while troubleshooting and repairing a wiring issue might require more time.

10. Can a DIY enthusiast fix OBDII code B3948:02 at home?

- Yes, depending on your skill level and access to tools, DIY enthusiasts can often diagnose and repair OBDII code B3948:02 at home. However, if you are unsure or uncomfortable with electrical work, it is best to seek professional help.