AutoCodes – Generic – P1479

P1479 Code - High Fan Control Primary Circuit Malfunction

Quick Answer

Monitors the High Fan Control (HFC) primary circuit output from the Powertrain Control Module (PCM). Common causes include Faulty Cooling Fan, Cooling Fan harness is open or shorted, Cooling Fan 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: P1479 indicates High Fan Control Primary Circuit Malfunction.
Common causes: Common causes include Faulty Cooling Fan, Cooling Fan harness is open or shorted, Cooling Fan 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 25,125

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 Aug 24, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1479 Description

Monitors the High Fan Control (HFC) primary circuit output from the Powertrain Control Module (PCM). The test fails if the HFC output commanded on (grounded), excessive current draw is detected on the HFC circuit or, with the HFC circuit commanded off, voltage is not detected on the HFC circuit (the PCM expects to detect VPWR voltage through the high speed FC relay coil to the HFC circuit).

OBDII Code P1479 - High Fan Control Primary Circuit Malfunction - AutoCodes.com — P1479 Code - High Fan Control Primary Circuit Malfunction

What does this mean?

What are the Possible Causes of the DTC P1479?

Faulty Cooling Fan
Cooling Fan harness is open or shorted
Cooling Fan circuit poor electrical connection
Faulty Powertrain Control Module (PCM)

How to Fix the DTC P1479?

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 P1479 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 P1479 code?

Need more information on how to fix the P1479 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P1479 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P1479 Audi — Brake Vacuum System Mechanical Malfunction
P1479 BMW — Brake Boost Vacuum System Mechanical Failure
P1479 Buick — Particulate Matter Sensor Sensitivity Factor Performance
P1479 Cadillac — Particulate Matter Sensor Sensitivity Factor Performance
P1479 Chevrolet — Particulate Matter Sensor Sensitivity Factor Performance
P1479 Chrysler — Transmission Fan Relay Condition
P1479 Dodge — Transmission Fan Relay Condition
P1479 Ford — High Fan Control Primary Circuit
P1479 GMC — Particulate Matter Sensor Sensitivity Factor Performance
P1479 Lincoln — High Fan Control Primary Circuit
P1479 Mazda — Cooling Fan Control Circuit Excessive Current Draw
P1479 Mercury — High Fan Control Primary Circuit
P1479 MINI — Brake Boost Vacuum System Mechanical Failure
P1479 Volkswagen — Brake Vacuum System Mechanical Malfunction

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 P1479 Code

1. What does the OBDII code P1479 mean?

P1479 indicates a malfunction in the high fan control primary circuit, meaning the system responsible for controlling the high-speed operation of the cooling fan is not functioning properly.

2. What are the common symptoms of code P1479?

Symptoms may include engine overheating, reduced air conditioning performance, an illuminated Check Engine Light, and the cooling fan not running at high speed when needed.

3. What causes the P1479 code to appear?

Common causes include a faulty cooling fan motor, damaged wiring or connectors in the fan circuit, a malfunctioning cooling fan relay, or a defective engine control module (ECM).

4. Can I drive my car with a P1479 code?

Driving with a P1479 code is not recommended, especially if the engine is overheating, as it can lead to severe engine damage.

5. How is the P1479 code diagnosed?

A technician will typically inspect the cooling fan circuit, check for damaged wiring, test the fan relay and motor, and use a scan tool to monitor the ECM's commands to the fan.

6. How can I fix the P1479 code?

Repairs may involve replacing the cooling fan motor, repairing damaged wiring, replacing a faulty fan relay, or, in rare cases, reprogramming or replacing the ECM.

7. What tools are needed to troubleshoot a P1479 code?

Tools might include a multimeter for electrical tests, a scan tool for reading live data and commands, and basic hand tools for inspecting and replacing components.

8. Can a failing cooling fan relay cause the P1479 code?

Yes, a failing or stuck cooling fan relay is a common cause of this code and should be tested during diagnosis.

9. How much does it cost to repair a P1479 code issue?

The cost varies depending on the root cause. Replacing a cooling fan motor or relay may cost $100-$400, whereas ECM replacement or programming could be more expensive.

10. Will resetting the Check Engine Light clear the P1479 code permanently?

Resetting the light might clear the code temporarily, but if the underlying issue is not fixed, the code and symptoms will return.