AutoCodes – Subaru – P0102 Subaru

P0102 Subaru Code - Mass or Volume Air Flow Circuit Low Input

Quick Answer

The Mass Air Flow (MAF) sensor is placed in the stream of the intake air. Common causes include Dirty Air Filter, Dirty Mass Air Flow (MAF) Sensor, Intake air leaks. 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: P0102 Subaru indicates Mass or Volume Air Flow Circuit Low Input.
Common causes: Common causes include Dirty Air Filter, Dirty Mass Air Flow (MAF) Sensor, Intake air leaks.
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 50,001

How popular is this code, among other codes? Medium

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on May 18, 2022

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0102 Subaru Description

The Mass Air Flow (MAF) sensor is placed in the stream of the intake air. It measures the intake flow rate by measuring a part of the entire intake flow. It consists of a hot film that is supplied with electric current from the Engine Control Module (ECM). The ECM controls the temperature of the hot film by a certain amount. The heat generated by the hot film is reduced as the intake air flows around it. The more air, the greater the heat loss. Therefore, the ECM must supply more electric current to maintain the temperature of the hot film as air flow increases. The ECM detects the air flow by means of this current change. The Diagnostic Trouble Code (DTC) will be set when the ECM detects that the MAF Sensor Signal is less than the factory specifications.

OBDII Code P0102 Subaru - Mass or Volume Air Flow Circuit Low Input - AutoCodes.com — P0102 Subaru Code - Mass or Volume Air Flow Circuit Low Input

What does this mean?

What are the Possible Causes of the DTC P0102 Subaru?

Dirty Air Filter
Dirty Mass Air Flow (MAF) Sensor
Intake air leaks
Faulty Mass Air Flow Sensor
Mass Air Flow Sensor harness is open or shorted
Mass Air Flow Sensor circuit poor electrical connection

How to Fix the DTC P0102 Subaru?

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 does this mean?

Code Tech Notes

Before replacing the Mass Air Flow (MAF) Sensor, try replacing the air filter and cleaning the Mass Air Flow Sensor with low compress air or Mass Air Flow Sensor Cleaner. Reset code and drive vehicle. If the code comes back, you must replace the Mass Air Flow Sensor to fix the problem.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0102 Subaru 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 P0102 Subaru Code

1. What are the common symptoms of OBDII code P0102 in a Subaru?

- Common symptoms include reduced engine power, poor fuel economy, rough idling, and stalling.

2. What are the typical causes of the P0102 code in a Subaru?

- The P0102 code is usually triggered by a faulty mass airflow sensor, damaged wiring or connectors, intake air leaks, or a clogged air filter.

3. How can I diagnose the cause of the P0102 code in my Subaru?

- To diagnose the issue, you can visually inspect the sensor and its connections, check for any air leaks in the intake system, and use a multimeter to test the sensor's voltage output.

4. Can a dirty air filter cause the P0102 code to appear?

- Yes, a dirty or clogged air filter can disrupt the airflow readings and potentially trigger the P0102 code in a Subaru.

5. What are some repair tips for fixing the P0102 code in a Subaru?

- Start by cleaning or replacing the air filter, inspecting and repairing any damaged wiring or connectors, and testing the mass airflow sensor for proper function.

6. Is it safe to continue driving my Subaru with the P0102 code present?

- It is not recommended to drive with the P0102 code active, as it can lead to poor engine performance and potential damage if left unresolved.

7. Can I reset the P0102 code in my Subaru using an OBDII scanner?

- Yes, you can use an OBDII scanner to clear the P0102 code after addressing the underlying issue, but it's important to ensure the problem is fixed to prevent the code from reappearing.

8. Will a Subaru dealership be able to diagnose and repair the P0102 code?

- Yes, Subaru dealerships have the expertise and diagnostic tools to accurately diagnose and repair the P0102 code in your vehicle.

9. How much does it typically cost to fix the P0102 code in a Subaru?

- The cost of fixing the P0102 code can vary depending on the root cause, but it may range from $100 for a simple repair like cleaning the sensor to $500 or more for sensor replacement or wiring repairs.

10. Can extreme weather conditions affect the occurrence of the P0102 code in a Subaru?

- Yes, extreme temperatures or humidity levels can impact the performance of the mass airflow sensor and potentially lead to the triggering of the P0102 code.

Discuss the causes and fixes for P0102 Subaru OBDII Code

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Nick Rondinella
Date: November 19, 2016 at 4:06 am

Thank you you have solidly answered my question and save me hundreds of dollars in troubleshooting labor cost. Thanks again gentlemen and ladies.

Reply to Comment
RC
Date: March 12, 2017 at 7:28 pm

My B9 threw this code when I unplugged the sensor to remove the air cleaner to change the R headlight bulb. Reset it and its fine. Don't know why it did this, key wasn't turned on and engine wasn't started. Just unplugged and re-plugged the connector back in. Update..I did turn the key on to check the light bulb, before I plugged it back in.DUH..Answered my own question. Did I mention the light bulbs ..H7.. are a BITCH to change? Poor design team!! Bet they haven't had to change a bulb. Grrr.

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