AutoCodes – GMC – P166B GMC

P166B GMC 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 GMC 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 3,844

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

What does this mean?

What are the Possible Causes of the DTC P166B GMC?

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 GMC?

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 GMC 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 GMC code?

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

Need Help with the Code?

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

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 GMC Code

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

The common symptoms include the Check Engine light illuminating on the dashboard, reduced engine performance, and possible issues with starting the vehicle.

2. What are the possible causes of OBDII code P166B GMC (Intake Air Heater Over Temperature)?

Possible causes include a faulty intake air heater, a malfunctioning intake air temperature sensor, wiring issues, or a problem with the PCM (Powertrain Control Module).

3. How can I diagnose the OBDII code P166B GMC (Intake Air Heater Over Temperature)?

Diagnosis involves using an OBDII scanner to retrieve the code, checking the intake air heater and temperature sensor for proper operation, inspecting the wiring for any damage, and testing the PCM if necessary.

4. Can I continue driving my vehicle with OBDII code P166B GMC (Intake Air Heater Over Temperature) present?

It is not recommended to continue driving the vehicle with this code present, as it can lead to further damage to the engine or emissions system. It is best to address the issue promptly.

5. How can I repair OBDII code P166B GMC (Intake Air Heater Over Temperature)?

Repairing this code may involve replacing the intake air heater, intake air temperature sensor, or repairing any damaged wiring. It is essential to follow the manufacturer's guidelines for proper repair procedures.

6. Are there any DIY tips for fixing OBDII code P166B GMC (Intake Air Heater Over Temperature)?

While some aspects of diagnosing and repairing this code can be done by DIY enthusiasts, it is recommended to consult with a professional mechanic for accurate diagnosis and repair to ensure the issue is resolved correctly.

7. Will resetting the Check Engine light resolve OBDII code P166B GMC (Intake Air Heater Over Temperature)?

Simply resetting the Check Engine light will not resolve the underlying issue causing the code. It is crucial to diagnose and address the root cause to prevent the code from reoccurring.

8. How long does it typically take to repair OBDII code P166B GMC (Intake Air Heater Over Temperature)?

The repair time can vary depending on the exact cause of the issue, but it may take a few hours to a full day to diagnose, repair, and test the system to ensure the problem is resolved effectively.

9. Can extreme weather conditions impact OBDII code P166B GMC (Intake Air Heater Over Temperature)?

Extreme cold weather can put more strain on the intake air heater, potentially leading to the over-temperature condition triggering the code. Ensuring the intake air system is functioning correctly is crucial in such conditions.

10. Is OBDII code P166B GMC (Intake Air Heater Over Temperature) a common issue in GMC vehicles?

While not as common as some other codes, issues related to the intake air heater system can occur in GMC vehicles, especially in older models or those exposed to harsh environmental conditions. Regular maintenance can help prevent such issues.