AutoCodes – Generic – B166B

B166B Code - Left Trailer Tow Lamp Control Circuit Low

Quick Answer

The Totally Integrated Power Module (TIPM) monitors the Left Trailer Tow Lamp Control. Common causes include Faulty Left Trailer Tow Lamp Bulb, Left Trailer Tow Lamp Bulb harness is open or shorted, Left Trailer Tow Lamp Bulb 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: B166B indicates Left Trailer Tow Lamp Control Circuit Low.
Common causes: Common causes include Faulty Left Trailer Tow Lamp Bulb, Left Trailer Tow Lamp Bulb harness is open or shorted, Left Trailer Tow Lamp Bulb 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 2,705

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 12, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B166B Description

The Totally Integrated Power Module (TIPM) monitors the Left Trailer Tow Lamp Control. The TIPM sets the OBDII code when the Left Trailer Tow Lamp Control is not to factory specifications.

OBDII Code B166B - Left Trailer Tow Lamp Control Circuit Low - AutoCodes.com — B166B Code - Left Trailer Tow Lamp Control Circuit Low

What does this mean?

What are the Possible Causes of the DTC B166B?

Faulty Left Trailer Tow Lamp Bulb
Left Trailer Tow Lamp Bulb harness is open or shorted
Left Trailer Tow Lamp Bulb circuit poor electrical connection
Faulty Totally Integrated Power Module (TIPM)

How to Fix the DTC B166B?

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 B166B 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.

Need more information about the B166B code?

Need more information on how to fix the B166B code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B166B code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

B166B Chrysler — Left Trailer Tow Lamp Control Circuit Low
B166B Dodge — Left Trailer Tow Lamp Control Circuit Low
B166B Jeep — Left Trailer Tow Lamp Control Circuit Low
B166B RAM — Left Trailer Tow Lamp Control Circuit Low

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 B166B Code

1. What are common symptoms of OBDII code B166B (Left Trailer Tow Lamp Control Circuit Low)?

- Common symptoms include the left trailer tow lamp not functioning properly or being dim, flickering, or completely non-functional.

2. What can cause OBDII code B166B to trigger?

- This code is typically triggered by issues such as a faulty left trailer tow lamp, damaged wiring, a blown fuse, or a malfunctioning control module.

3. How can I diagnose the cause of OBDII code B166B?

- You can start by visually inspecting the left trailer tow lamp and its wiring for any damage or loose connections. Use a multimeter to test the voltage at the lamp and along the circuit to pinpoint the issue.

4. What are some repair tips for OBDII code B166B?

- Begin by checking and replacing any blown fuses related to the left trailer tow lamp. Ensure the lamp is in good working condition and replace it if necessary. Repair any damaged wiring or connectors.

5. Can OBDII code B166B be safely ignored?

- Ignoring this code is not recommended, as it indicates a problem with the left trailer tow lamp circuit that could affect the safety of your vehicle and others on the road.

6. How do I reset OBDII code B166B after making repairs?

- After addressing the underlying issue causing the code, you can reset it using an OBDII scanner or by disconnecting the vehicle's battery for a few minutes to clear the code.

7. Are there any common mistakes to avoid when dealing with OBDII code B166B?

- Avoid simply replacing the left trailer tow lamp without checking the entire circuit for issues. Also, ensure any repairs are done correctly to prevent the code from recurring.

8. Can a DIY enthusiast fix OBDII code B166B at home?

- Depending on the root cause, DIY enthusiasts with some automotive repair experience may be able to diagnose and repair OBDII code B166B at home by following repair guides and using the necessary tools.

9. Is it necessary to seek professional help for OBDII code B166B?

- If you are unsure about diagnosing or repairing the issue causing OBDII code B166B, it's advisable to seek help from a qualified mechanic or technician to ensure the problem is properly addressed.

10. How can I prevent OBDII code B166B from occurring in the future?

- Regularly inspecting the trailer tow lamp circuit, ensuring proper maintenance of the trailer lighting system, and promptly addressing any issues can help prevent the recurrence of OBDII code B166B.