AutoCodes – GMC – P0405 GMC

P0405 GMC Code - Exhaust Gas Recirculation Position Sensor Circuit Low Voltage

Quick Answer

The Engine Control Module (ECM) uses the Exhaust Gas Recirculation (EGR) position sensor to determine the position of the EGR valve. Common causes include Faulty Exhaust Gas Recirculation (EGR) Valve, Exhaust Gas Recirculation Valve harness is open or shorted, Exhaust Gas Recirculation Valve circuit poor electrical connection. 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: P0405 GMC indicates Exhaust Gas Recirculation Position Sensor Circuit Low Voltage.
Common causes: Common causes include Faulty Exhaust Gas Recirculation (EGR) Valve, Exhaust Gas Recirculation Valve harness is open or shorted, Exhaust Gas Recirculation Valve circuit poor electrical connection.
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.

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Code Popularity 10,002

How popular is this code, among other codes? Low

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Mar 24, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0405 GMC Description

The Engine Control Module (ECM) uses the Exhaust Gas Recirculation (EGR) position sensor to determine the position of the EGR valve. The ECM sends a reference voltage through the 5 V reference circuit to the EGR position sensor. The ECM provides a voltage return path for the sensor through the low reference circuit. A variable voltage signal, based on the EGR valve position, is sent from the sensor to the ECM through the EGR position sensor signal circuit. The Diagnostic Trouble Code (DTC) will be set when the ECM detects that the EGR position sensor voltage is less than 0.25 V for greater than 5 s.

OBDII Code P0405 GMC - Exhaust Gas Recirculation Position Sensor Circuit Low Voltage - AutoCodes.com — P0405 GMC Code - Exhaust Gas Recirculation Position Sensor Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P0405 GMC?

Faulty Exhaust Gas Recirculation (EGR) Valve
Exhaust Gas Recirculation Valve harness is open or shorted
Exhaust Gas Recirculation Valve circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P0405 GMC?

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 P0405 GMC 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 P0405 GMC code?

Need more information on how to fix the P0405 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

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Information for Specific GMC Models

P0405 2014 GMC Sierra — Exhaust Gas Recirculation Position Sensor Circuit Low Voltage
P0405 2015 GMC Sierra — Exhaust Gas Recirculation Position Sensor Circuit Low Voltage
P0405 2016 GMC Sierra — Exhaust Gas Recirculation Position Sensor Circuit Low Voltage
P0405 2017 GMC Sierra — Exhaust Gas Recirculation Position Sensor Circuit Low Voltage
P0405 2018 GMC Sierra — Exhaust Gas Recirculation Position Sensor Circuit Low Voltage

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 P0405 GMC Code

1. What are the common symptoms of OBDII code P0405 GMC?

The common symptoms of code P0405 include rough idling, reduced engine performance, stalling, and illuminated Check Engine Light.

2. What does the OBDII code P0405 GMC indicate?

Code P0405 indicates a problem with the Exhaust Gas Recirculation (EGR) Position Sensor Circuit, specifically low voltage detected by the engine control module.

3. What are the possible causes of OBDII code P0405 GMC?

Possible causes of code P0405 include a faulty EGR position sensor, damaged wiring or connectors in the EGR circuit, carbon buildup in the EGR system, or a malfunctioning engine control module.

4. How can I diagnose the issue causing OBDII code P0405 GMC?

Diagnosing code P0405 involves inspecting the EGR position sensor and its wiring for damage, testing the sensor's voltage output, checking for carbon buildup in the EGR system, and scanning the engine control module for related error codes.

5. Can I drive my vehicle with OBDII code P0405 GMC?

It is not recommended to drive your vehicle with code P0405 present, as it can lead to poor engine performance, increased emissions, and potential damage to the EGR system over time.

6. How can I repair OBDII code P0405 GMC?

Repairing code P0405 typically involves replacing the EGR position sensor if faulty, repairing damaged wiring or connectors, cleaning carbon deposits in the EGR system, and resetting the engine control module.

7. Will resetting the Check Engine Light resolve OBDII code P0405 GMC?

Simply resetting the Check Engine Light without addressing the underlying issue causing code P0405 will not resolve the problem. It is important to diagnose and repair the root cause of the code.

8. How much does it cost to fix OBDII code P0405 GMC?

The cost to fix code P0405 can vary depending on the cause of the issue. Replacing the EGR position sensor or repairing wiring may cost between $100 to $300, excluding labor charges.

9. Can a dirty EGR valve cause OBDII code P0405 GMC?

Yes, a dirty or clogged EGR valve can restrict the flow of exhaust gases and cause issues with the EGR position sensor, potentially triggering code P0405.

10. How can I prevent OBDII code P0405 GMC from recurring?

Regular maintenance, such as cleaning the EGR system components, using high-quality fuel, and addressing any engine performance issues promptly, can help prevent the recurrence of code P0405.