AutoCodes – Generic – P229E

P229E Code - NOx Sensor Circuit Bank 2

Quick Answer

The reductant system uses two Nitrogen Oxide (NOx) sensors to monitor the amount of NOx in the engine's exhaust gas. Common causes include Faulty Nitrogen Oxide (NOx) Sensor Bank 2, Nitrogen Oxide (NOx) Sensor Bank 2 harness is open or shorted, Nitrogen Oxide (NOx) Sensor Bank 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: P229E indicates NOx Sensor Circuit Bank 2.
Common causes: Common causes include Faulty Nitrogen Oxide (NOx) Sensor Bank 2, Nitrogen Oxide (NOx) Sensor Bank 2 harness is open or shorted, Nitrogen Oxide (NOx) Sensor Bank 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 43,223

How popular is this code, among other codes? Medium

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 May 12, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P229E Description

The reductant system uses two Nitrogen Oxide (NOx) sensors to monitor the amount of NOx in the engine's exhaust gas. The first sensor is located at the outlet of the turbocharger and monitors the engine out NOx level. The second NOx sensor is located between the Selective Catalytic Reduction (SCR) and the Diesel Particulate Filter (DPF) and monitors NOx levels downstream of the SCR. The second NOx sensor also provides the Engine Control Module (ECM) with information on the exhaust oxygen level during DPF regeneration.
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 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 (DEF) or reductant added by varying the reductant injector duty cycle in response to changes in engine exhaust out 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.

OBDII Code P229E - NOx Sensor Circuit Bank 2 - AutoCodes.com — P229E Code - NOx Sensor Circuit Bank 2

What does this mean?

What are the Possible Causes of the DTC P229E?

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

How to Fix the DTC P229E?

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 P229E 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 P229E code?

Need more information on how to fix the P229E code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P229E code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P229E Chevrolet — NOx Sensor Circuit Bank 2
P229E GMC — NOx Sensor Circuit Bank 2

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 P229E Code

1. What does the OBDII code P229E indicate?

The P229E code signifies an issue with the NOx (Nitrogen Oxide) sensor circuit on Bank 2 of the engine, indicating a malfunction related to the sensor's signal or operation.

2. What are the common symptoms of code P229E?

Symptoms might include a check engine light, reduced fuel efficiency, poor engine performance, or increased emissions. In some cases, there may be no noticeable symptoms other than the illuminated check engine light.

3. What could cause the OBDII code P229E to appear?

Potential causes include faulty NOx sensors, wiring issues in the NOx sensor circuit such as shorts or opens, problems with the NOx sensor connector, or issues with the engine control module (ECM).

4. How can I diagnose the P229E code?

Diagnosis typically involves using an OBDII scanner to confirm the code, visually inspecting the NOx sensor and associated wiring for damage, and checking the sensor's operation with a multimeter. Advanced diagnostic steps might include monitoring NOx sensor readings using specialized diagnostic equipment.

5. What steps should I take to fix the NOx sensor circuit issue indicated by code P229E?

Repair procedures may include replacing the faulty NOx sensor, repairing or replacing damaged wiring or connectors, or in some cases, updating or replacing the ECM if it is found to be defective.

6. Is it safe to drive a vehicle with the P229E code?

While it might be safe to drive for a short period, driving with this code can lead to increased emissions, and over time, may affect engine performance and fuel efficiency. It is advisable to address the issue as soon as possible to avoid potential further damage.

7. Can the P229E code affect the vehicle's fuel economy?

Yes, a malfunctioning NOx sensor can result in improper feedback to the engine's control system, potentially leading to inefficient combustion and reduced fuel economy.

8. Does the P229E code specifically affect certain types of vehicles more than others?

The P229E code can appear on any vehicle equipped with NOx sensors, particularly those with diesel engines where NOx control is crucial for meeting emissions standards. However, the likelihood of encountering this code can vary depending on the make and model.

9. What is the typical cost associated with repairing the P229E code?

Costs can vary widely depending on the vehicle and the specific repair needed. NOx sensor replacements can range from $200 to $600, while wiring repairs might cost less unless extensive damage exists. Labor costs will vary based on the complexity of the job and the local labor rate.