AutoCodes – Mercury – P166A Mercury

P166A Mercury Code - Restraints Deployment Communication Circuit

Quick Answer

This Diagnostic Trouble Code (DTC) sets when the Powertrain Control Module (PCM) detects an open or short in the IES circuit. Common causes include IES circuit open, IES circuit short to ground, IES circuit short to voltage. 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: P166A Mercury indicates Restraints Deployment Communication Circuit.
Common causes: Common causes include IES circuit open, IES circuit short to ground, IES circuit short to voltage.
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 1,035

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 May 21, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P166A Mercury Description

This Diagnostic Trouble Code (DTC) sets when the Powertrain Control Module (PCM) detects an open or short in the IES circuit.

OBDII Code P166A Mercury - Restraints Deployment Communication Circuit - AutoCodes.com — P166A Mercury Code - Restraints Deployment Communication Circuit

What does this mean?

What are the Possible Causes of the DTC P166A Mercury?

IES circuit open
IES circuit short to ground
IES circuit short to voltage

How to Fix the DTC P166A Mercury?

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 P166A Mercury 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 P166A Mercury Code

1. What are common symptoms of OBDII code P166A in a Mercury related to the Restraints Deployment Communication Circuit?

- Common symptoms include the airbag warning light staying on, loss of communication with the restraint control module, and potential issues with the airbag system deployment.

2. What are some possible causes of OBDII code P166A in a Mercury?

- Possible causes include a faulty restraint control module, damaged wiring or connectors in the communication circuit, or a malfunctioning airbag control unit.

3. How can I diagnose the Restraints Deployment Communication Circuit issue causing OBDII code P166A in my Mercury?

- Diagnosis involves using a scan tool to read the code, checking the wiring and connectors for damage, and testing the restraint control module for proper communication.

4. Can I still drive my Mercury with OBDII code P166A related to the Restraints Deployment Communication Circuit?

- It is not recommended to drive the vehicle with this code present, as it indicates potential issues with the airbag system that could affect safety in the event of a collision.

5. Are there any repair tips for fixing OBDII code P166A in a Mercury?

- Repair tips include checking and repairing any damaged wiring or connectors, replacing the faulty restraint control module if necessary, and resetting the code after repairs are completed.

6. How serious is OBDII code P166A in a Mercury related to the Restraints Deployment Communication Circuit?

- This code is considered serious as it indicates a potential problem with the airbag system, which is a crucial safety feature in the vehicle.

7. Can a DIY enthusiast fix OBDII code P166A in a Mercury, or is professional help required?

- While some basic troubleshooting and repairs can be done by a DIY enthusiast, dealing with airbag system issues may require specialized knowledge and equipment, so professional help is recommended.

8. How much does it typically cost to repair OBDII code P166A in a Mercury?

- The cost of repairs can vary depending on the exact cause of the issue, but it may involve expenses for parts replacement, diagnostic services, and labor, potentially ranging from a few hundred to over a thousand dollars.

9. Will resetting the OBDII code P166A in a Mercury make the issue go away permanently?

- Resetting the code may temporarily clear the warning light, but if the underlying issue with the Restraints Deployment Communication Circuit is not addressed, the code is likely to reappear.

10. How can I prevent OBDII code P166A related to the Restraints Deployment Communication Circuit from occurring in my Mercury in the future?

- Regularly inspecting and maintaining the airbag system components, ensuring proper wiring connections, and addressing any warning lights promptly can help prevent this code from appearing in the future.