AutoCodes – Chevrolet – P1004 Chevrolet

P1004 Chevrolet Code - NOx Sensor 2 Slow Response

Quick Answer

The Nitrogen Oxides (NOx) sensors are part of the selective catalytic reduction system, a device used to reduce NOx emission on diesel engines. Common causes include Faulty Nitrogen Oxides (NOx) Sensor 2, Nitrogen Oxides Sensor 2 harness is open or shorted, Nitrogen Oxides Sensor 2 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: P1004 Chevrolet indicates NOx Sensor 2 Slow Response.
Common causes: Common causes include Faulty Nitrogen Oxides (NOx) Sensor 2, Nitrogen Oxides Sensor 2 harness is open or shorted, Nitrogen Oxides Sensor 2 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.

Save to My Repairs My Repairs

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

Code Popularity 1,478

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 Mar 24, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
Add Comment

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

Code P1004 Chevrolet Description

The Nitrogen Oxides (NOx) sensors are part of the selective catalytic reduction system, a device used to reduce NOx emission on diesel engines. There are two NOx sensors, one placed upstream of selective catalytic reduction, to measure inlet NOx concentration, and one placed downstream. They are connected with the control module via CAN and all the information is exchanged through it. Since it is a smart sensor, all the electrical monitoring is performed inside the sensor and only the results are sent to the Engine Control Module (ECM). Each NOx sensor contains a sensing cell, a pumping cell, and a heater. A sample of exhaust gas passes through a diffusion gap between the sensing cell and the pumping cell. The NOx sensor maintains a constant reference voltage across the sensing cell. An electronic circuit within the sensor controls the pump current through the pumping cell in order to maintain a constant voltage in the sensing cell. The amount of current required to maintain the reference voltage in the sensing cell is proportional to the concentration of NOx in the exhaust. The ECM varies the amount of diesel exhaust fluid (reductant) added by varying the reductant injector duty cycle in response to changes in engine exhaust NOx levels. The smart NOx sensors consist of two components, the NOx module and the NOx sensor element that are serviced as a unit. A circuit or performance condition with a NOx sensor is detected by the NOx sensor module. The smart NOx sensor module communicates the condition to the ECM over the serial data line. The ECM sets a DTC when a serial data message is received from the NOx sensor module. The Diagnostic Trouble Code (DTC) will be set if the ECM software detects a fault in the NOx sensor circuitry or a performance fault in the NOx sensor for greater than 2 s.

OBDII Code P1004 Chevrolet - NOx Sensor 2 Slow Response - AutoCodes.com — P1004 Chevrolet Code - NOx Sensor 2 Slow Response

What does this mean?

What are the Possible Causes of the DTC P1004 Chevrolet?

Faulty Nitrogen Oxides (NOx) Sensor 2
Nitrogen Oxides Sensor 2 harness is open or shorted
Nitrogen Oxides Sensor 2 circuit poor electrical connection

How to Fix the DTC P1004 Chevrolet?

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 P1004 Chevrolet 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 P1004 Chevrolet code?

Need more information on how to fix the P1004 Chevrolet code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P1004 Chevrolet code diagnosed by a professional: Find a repair shop in your area

Information for Specific Chevrolet Models

P1004 2014 Chevrolet Silverado — NOx Sensor 2 Slow Response
P1004 2015 Chevrolet Silverado — NOx Sensor 2 Slow Response
P1004 2016 Chevrolet Silverado — NOx Sensor 2 Slow Response
P1004 2017 Chevrolet Silverado — NOx Sensor 2 Slow Response
P1004 2018 Chevrolet Silverado — NOx Sensor 2 Slow Response

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 P1004 Chevrolet Code

1. What are the common symptoms of OBDII code P1004 Chevrolet (NOx Sensor 2 Slow Response)?

- The common symptoms include decreased fuel efficiency, rough engine performance, and illuminated Check Engine light.

2. What are the potential causes of OBDII code P1004 Chevrolet (NOx Sensor 2 Slow Response)?

- The causes may include a faulty NOx sensor, issues with the wiring or connectors, exhaust system leaks, or a malfunctioning engine control module (ECM).

3. How serious is OBDII code P1004 Chevrolet (NOx Sensor 2 Slow Response)?

- While this code may not cause immediate harm to the vehicle, it can lead to increased emissions and reduced engine performance if left unresolved.

4. How can I diagnose OBDII code P1004 Chevrolet (NOx Sensor 2 Slow Response)?

- Diagnosis typically involves using an OBDII scanner to retrieve the code, inspecting the NOx sensor and its wiring, and performing system tests to pinpoint the issue.

5. Can I drive my vehicle with OBDII code P1004 Chevrolet (NOx Sensor 2 Slow Response)?

- It is generally safe to drive the vehicle for a short period with this code, but it is recommended to address the issue promptly to prevent any potential long-term damage.

6. How can I repair OBDII code P1004 Chevrolet (NOx Sensor 2 Slow Response)?

- Repair options include replacing the faulty NOx sensor, repairing any damaged wiring or connectors, fixing exhaust leaks, or reprogramming the ECM if necessary.

7. Are there any DIY tips for fixing OBDII code P1004 Chevrolet (NOx Sensor 2 Slow Response)?

- While some basic checks like inspecting wiring connections can be done by DIY enthusiasts, it is recommended to consult a professional for a proper diagnosis and repair.

8. How much does it cost to fix OBDII code P1004 Chevrolet (NOx Sensor 2 Slow Response)?

- The cost of repairs can vary depending on the exact cause of the issue, but it may range from $200 to $600, including parts and labor.

9. Can resetting the Check Engine light resolve OBDII code P1004 Chevrolet (NOx Sensor 2 Slow Response)?

- Simply resetting the light will not fix the underlying issue causing the code. It is important to diagnose and address the root cause of the problem.

10. How long does it take to repair OBDII code P1004 Chevrolet (NOx Sensor 2 Slow Response)?

- The repair time can vary based on the complexity of the issue and the availability of parts. In general, it may take a few hours to a day to complete the repairs.