AutoCodes – Buick – P1004 Buick

P1004 Buick 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 Buick 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.

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Code Popularity 791

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

What does this mean?

What are the Possible Causes of the DTC P1004 Buick?

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 Buick?

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 Buick 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 P1004 Buick Code

1. What are the common symptoms of OBDII code P1004 in a Buick related to NOx Sensor 2 Slow Response?

- Common symptoms include reduced fuel efficiency, engine misfires, and the illumination of the check engine light.

2. What typically causes the NOx Sensor 2 Slow Response code (P1004) in a Buick?

- The code is often triggered by a faulty NOx sensor, wiring issues, or problems with the exhaust system.

3. How can I diagnose the cause of OBDII code P1004 in my Buick?

- A diagnostic scan tool can help pinpoint the issue by reading the specific error codes and data related to the NOx sensor's performance.

4. What are the potential repair options for resolving the NOx Sensor 2 Slow Response code in a Buick?

- Repair options may include replacing the NOx sensor, repairing damaged wiring, or addressing issues in the exhaust system.

5. Can I continue driving my Buick with the P1004 code related to NOx Sensor 2 Slow Response?

- It is not recommended to ignore this code as it can lead to further engine damage and affect emissions compliance.

6. How much does it typically cost to repair OBDII code P1004 in a Buick?

- The cost of repairs can vary depending on the specific cause of the issue, but it may range from a few hundred to a thousand dollars.

7. Are there any maintenance tips to prevent the recurrence of the NOx Sensor 2 Slow Response code in my Buick?

- Regularly servicing your vehicle, including inspecting the exhaust system and sensors, can help prevent issues leading to this code.

8. Can a DIY enthusiast fix the P1004 code related to NOx Sensor 2 Slow Response in a Buick?

- While some may attempt DIY repairs, it is often recommended to have a professional mechanic diagnose and fix the issue due to the complexity of the system.

9. Will resetting the check engine light resolve the NOx Sensor 2 Slow Response code in my Buick?

- Resetting the check engine light may temporarily turn it off, but the underlying issue causing the code will still need to be addressed to prevent it from reoccurring.

10. Is the NOx Sensor 2 Slow Response code a common issue in Buick vehicles?

- While it may not be as common as some other codes, issues with NOx sensors leading to P1004 can occur in Buick vehicles and should be addressed promptly.