AutoCodes – Lexus – P1605 Lexus

P1605 Lexus Code - Engine Rough Idling

Quick Answer

After starting the engine, this Diagnostic Trouble Code (DTC) is stored if the engine speed drops below the set speed. Common causes include Air Leak in Intake System, Faulty Mass Air Flow (MAF) sensor, Faulty Engine Coolant Temperature Sensor. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means: P1605 Lexus indicates Engine Rough Idling.
Common causes: Common causes include Air Leak in Intake System, Faulty Mass Air Flow (MAF) sensor, Faulty Engine Coolant Temperature Sensor.
Severity: Moderate - service should be scheduled soon.
Can I drive?: The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

Save to My Repairs Step-by-Step Diagnostic Guide My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 29,945

How popular is this code, among other codes? Low

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Sep 06, 2022

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P1605 Lexus Description

After starting the engine, this Diagnostic Trouble Code (DTC) is stored if the engine speed drops below the set speed. With the engine running, the engine stops (the engine speed drops to 200 RPM or less) without the ignition switch being operated for 0.5 seconds or more. It is necessary to check if the vehicle has run out of fuel before performing troubleshooting, as this DTC is also stored when the engine stalls due to running out of fuel.

OBDII Code P1605 Lexus - Engine Rough Idling - AutoCodes.com — P1605 Lexus Code - Engine Rough Idling

What does this mean?

What are the Possible Causes of the DTC P1605 Lexus?

Air Leak in Intake System
Faulty Mass Air Flow (MAF) sensor
Faulty Engine Coolant Temperature Sensor
Faulty Fuel Pump
Faulty Throttle Body Assembly
Faulty Engine Control Module (ECM)

How to Fix the DTC P1605 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 P1605 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.

Need more information about the P1605 Lexus code?

Need more information on how to fix the P1605 Lexus code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P1605 Lexus 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 P1605 Lexus Code

1. What does the OBDII code P1605 mean for a Lexus?

P1605 indicates "Engine Rough Idling," which means the engine is not running smoothly at idle due to a potential fault in the engine control system.

2. What are common symptoms of the P1605 code in a Lexus?

Symptoms include rough idling, engine stalling, poor acceleration, and possibly the Check Engine Light being illuminated.

3. What causes the P1605 code on a Lexus?

Common causes include a malfunctioning Idle Air Control (IAC) valve, dirty throttle body, faulty sensors (like the Mass Air Flow sensor or oxygen sensor), or vacuum leaks.

4. Can a dirty throttle body trigger the P1605 code?

Yes, a dirty or clogged throttle body can disrupt airflow, leading to rough idling and triggering the P1605 code.

5. How can I fix the P1605 code on my Lexus?

Start by cleaning the throttle body and inspecting the Idle Air Control (IAC) valve. Check for vacuum leaks and faulty sensors, replacing components as needed.

6. Is it safe to drive with the P1605 code active on a Lexus?

Driving with this code may result in engine stalling or reduced performance. Itâ€™s recommended to address the issue promptly to avoid further damage.

7. Can a vacuum leak cause the P1605 code in a Lexus?

Yes, a vacuum leak can disrupt the air-fuel mixture, causing rough idling and triggering the P1605 code.

8. Will replacing the Idle Air Control valve fix the P1605 code?

If the IAC valve is malfunctioning, replacing it can resolve the issue. However, other components should also be inspected.

9. Can bad spark plugs cause the P1605 code in a Lexus?

While spark plugs can cause rough idling, the P1605 code is typically related to idle control systems. Still, itâ€™s worth inspecting them as part of troubleshooting.

10. How much does it cost to fix the P1605 code on a Lexus?

Repair costs vary based on the issue but may range from $150 to $500, depending on whether cleaning, sensor replacement, or more extensive repairs are needed.