AutoCodes – Lexus – P0111 Lexus

P0111 Lexus Code - Intake Air Temperature Sensor Gradient Too High

Quick Answer

The Intake Air Temperature (IAT), mounted on the Mass Air Flow meter sub-assembly, monitors the intake air temperature. Common causes include Dirty air filter, Faulty Intake Air Temperature (IAT) Sensor (Part of the Mass Air Flow [MAF] Sensor), Intake Air Temperature sensor harness is open or shorted. 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: P0111 Lexus indicates Intake Air Temperature Sensor Gradient Too High.
Common causes: Common causes include Dirty air filter, Faulty Intake Air Temperature (IAT) Sensor (Part of the Mass Air Flow [MAF] Sensor), Intake Air Temperature sensor harness is open or shorted.
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 4,667

How popular is this code, among other codes? Low

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 Aug 22, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0111 Lexus Description

The Intake Air Temperature (IAT), mounted on the Mass Air Flow meter sub-assembly, monitors the intake air temperature. The intake air temperature sensor has a built-in thermistor with a resistance that varies according to the temperature of the intake air. When the intake air temperature is low, the resistance of the thermistor increases. When the temperature is high, the resistance drops. These variations in resistance are transmitted to the Engine Control Module (ECM) as voltage changes.
The ECM performs OBD II monitoring based on the values from the intake air temperature sensor. If there is no change of the sensor value within the normal range, the ECM will not be able to perform OBD II monitoring or will misdiagnose that there is a malfunction in the sensor. The ECM detects when the intake air temperature sensor value is stuck by performing monitoring after the ignition switch is turned off or the engine is started (short soak or long soak).

OBDII Code P0111 Lexus - Intake Air Temperature Sensor Gradient Too High - AutoCodes.com — P0111 Lexus Code - Intake Air Temperature Sensor Gradient Too High

What does this mean?

What are the Possible Causes of the DTC P0111 Lexus?

Dirty air filter
Faulty Intake Air Temperature (IAT) Sensor (Part of the Mass Air Flow [MAF] Sensor)
Intake Air Temperature sensor harness is open or shorted
Intake Air Temperature sensor circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P0111 Lexus?

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 P0111 Lexus 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 P0111 Lexus Code

1. What does the OBDII code P0111 mean on a Lexus?

P0111 indicates that the Engine Control Module (ECM) has detected an issue with the Intake Air Temperature (IAT) sensor, specifically that the temperature gradient is too high or inconsistent.

2. What are the common symptoms of P0111 in a Lexus?

Symptoms may include poor engine performance, reduced fuel efficiency, difficulty starting the engine, and the Check Engine Light turning on.

3. What causes the P0111 code to appear in a Lexus?

Common causes include a faulty IAT sensor, wiring issues such as shorts or corrosion, an air intake system leak, or a malfunctioning ECM.

4. Can I drive my Lexus with a P0111 code?

While it may be safe to drive for a short period, ignoring the issue can lead to reduced engine performance and potential long-term damage. It's best to address the problem promptly.

5. How do I diagnose the P0111 code on my Lexus?

Start by using an OBDII scanner to confirm the code, then inspect the IAT sensor, its wiring, and the air intake system for visible damage, corrosion, or loose connections.

6. How can I fix the P0111 code on my Lexus?

Repairs may include replacing the IAT sensor, repairing damaged wires, cleaning or replacing air intake components, or reprogramming the ECM if necessary.

7. How much does it cost to fix the P0111 code on a Lexus?

Repair costs vary but typically range from $50 to $200 for parts and labor, depending on whether you replace the sensor, fix wiring, or address other issues.

8. Can a dirty air filter cause the P0111 code on a Lexus?

Yes, a clogged or dirty air filter can restrict airflow, potentially causing inconsistent readings from the IAT sensor and triggering the P0111 code.

9. Where is the IAT sensor located on a Lexus?

The IAT sensor is usually located in the air intake system, near the air filter housing or integrated into the mass airflow (MAF) sensor.

10. How can I prevent the P0111 code from recurring on my Lexus?

Regular maintenance, such as cleaning or replacing the air filter, inspecting the air intake system, and ensuring electrical connections are secure, can help prevent this code.