AutoCodes – Generic – P166B

P166B Code - Intake Air Heater Over Temperature

Quick Answer

The Engine Control Module (ECM) monitors the Intake Air (IA) Heater. Common causes include Faulty Intake Air (IA) Heater, Intake Air (IA) Heater harness is open or shorted, Intake Air (IA) Heater 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: P166B indicates Intake Air Heater Over Temperature.
Common causes: Common causes include Faulty Intake Air (IA) Heater, Intake Air (IA) Heater harness is open or shorted, Intake Air (IA) Heater 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 8,871

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 Jan 06, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P166B Description

The Engine Control Module (ECM) monitors the Intake Air (IA) Heater. The ECM sets the OBDII code when the Intake Air (IA) Heater is not to factory specifications.

OBDII Code P166B - Intake Air Heater Over Temperature - AutoCodes.com — P166B Code - Intake Air Heater Over Temperature

What does this mean?

What are the Possible Causes of the DTC P166B?

Faulty Intake Air (IA) Heater
Intake Air (IA) Heater harness is open or shorted
Intake Air (IA) Heater circuit poor electrical connection

How to Fix the DTC P166B?

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 P166B 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 P166B code?

Need more information on how to fix the P166B code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P166B code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P166B Buick — Intake Air Heater Over Temperature
P166B Cadillac — Intake Air Heater Over Temperature
P166B Chevrolet — Intake Air Heater Over Temperature
P166B GMC — Intake Air Heater Over Temperature

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 P166B Code

1. What are the common symptoms of OBDII code P166B (Intake Air Heater Over Temperature)?

The common symptoms include the Check Engine Light turning on, reduced engine performance, and possible overheating of the intake air heater.

2. What are the possible causes of OBDII code P166B?

Some possible causes of code P166B include a faulty intake air heater, a malfunctioning intake air temperature sensor, or issues with the engine control module (ECM).

3. How can I diagnose OBDII code P166B?

Diagnosing code P166B usually involves using a diagnostic scanner to retrieve the code, checking the intake air heater and temperature sensor for any issues, and testing the ECM for proper function.

4. Can driving with OBDII code P166B cause further damage to the vehicle?

Continuing to drive with code P166B may lead to reduced fuel efficiency, potential engine overheating, and further damage to the intake air system components.

5. How can I repair OBDII code P166B?

Repairing code P166B typically involves replacing a faulty intake air heater, fixing any issues with the intake air temperature sensor, or reprogramming the ECM if necessary.

6. Is it safe to clear OBDII code P166B without fixing the underlying issue?

Clearing the code without addressing the root cause can temporarily turn off the Check Engine Light, but the issue will likely reoccur, potentially leading to more serious problems over time.

7. Are there any DIY tips for troubleshooting OBDII code P166B?

DIY tips for troubleshooting code P166B include checking the intake air heater connections, inspecting the wiring for any damage, and ensuring the intake air system is clean and free of obstructions.

8. How much does it typically cost to repair OBDII code P166B at a mechanic?

The cost of repairing code P166B can vary depending on the specific issue, but it may range from $200 to $500 at a mechanic, including parts and labor.

9. Can a faulty intake air heater cause other OBDII codes to appear?

Yes, a faulty intake air heater can cause other related OBDII codes to appear, such as codes related to intake air temperature sensor malfunctions or ECM communication issues.

10. Is it recommended to drive the vehicle with OBDII code P166B or should I seek immediate repair?

It is recommended to seek repair as soon as possible when OBDII code P166B appears to prevent potential damage to the engine and ensure optimal performance of the vehicle.