AutoCodes – Buick – P2628 Buick

P2628 Buick Code - HO2S Pump Current Trim Circuit High Voltage Sensor 1

Quick Answer

The oxygen content of the exhaust is measured via the Nitrogen Oxide (NOx) sensors. Common causes include Faulty Nitrogen Oxides Sensor 1, Nitrogen Oxides Sensor 1 harness is open or shorted, Nitrogen Oxides Sensor 1 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: P2628 Buick indicates HO2S Pump Current Trim Circuit High Voltage Sensor 1.
Common causes: Common causes include Faulty Nitrogen Oxides Sensor 1, Nitrogen Oxides Sensor 1 harness is open or shorted, Nitrogen Oxides Sensor 1 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 401

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Aug 01, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P2628 Buick Description

The oxygen content of the exhaust is measured via the Nitrogen Oxide (NOx) sensors. The 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 Diagnostic Trouble Code (DTC) when a serial data message is received from the NOx sensor module.

OBDII Code P2628 Buick - HO2S Pump Current Trim Circuit High Voltage Sensor 1 - AutoCodes.com — P2628 Buick Code - HO2S Pump Current Trim Circuit High Voltage Sensor 1

What does this mean?

What are the Possible Causes of the DTC P2628 Buick?

Faulty Nitrogen Oxides Sensor 1
Nitrogen Oxides Sensor 1 harness is open or shorted
Nitrogen Oxides Sensor 1 circuit poor electrical connection

How to Fix the DTC P2628 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 P2628 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 P2628 Buick Code

1. What are the common symptoms of OBDII code P2628 on a Buick?

- Common symptoms include poor engine performance, rough idling, decreased fuel efficiency, and the illumination of the check engine light.

2. What can cause the HO2S Pump Current Trim Circuit High Voltage Sensor 1 code P2628 on a Buick?

- This code is typically triggered by issues with the Heated Oxygen Sensor (HO2S) pump current trim circuit, such as sensor wiring faults, a faulty sensor, or problems with the sensor heater circuit.

3. How serious is the P2628 OBDII code on a Buick?

- While this code may not cause immediate engine failure, it should be addressed promptly to prevent potential long-term damage to the vehicle's catalytic converter and overall engine performance.

4. Can I continue driving my Buick with the P2628 code?

- It is generally not recommended to drive the vehicle with an active P2628 code, as it can lead to reduced fuel efficiency and potential damage to the catalytic converter over time.

5. How do I diagnose and repair the P2628 code on my Buick?

- Diagnosis involves inspecting the HO2S pump current trim circuit for any visible damage or loose connections. Repair may include replacing the HO2S sensor, repairing wiring faults, or addressing issues with the sensor heater circuit.

6. Will resetting the Check Engine Light resolve the P2628 code on a Buick?

- Simply resetting the Check Engine Light may temporarily turn it off, but the underlying issue causing the P2628 code will still need to be diagnosed and repaired to prevent the code from reoccurring.

7. Is it possible to fix the P2628 code on a Buick without professional help?

- While some basic troubleshooting steps can be taken by DIY enthusiasts, diagnosing and repairing the P2628 code may require specialized tools and expertise, so seeking professional assistance is usually recommended.

8. How much does it cost to repair the P2628 code on a Buick?

- The cost of repairing the P2628 code can vary depending on the exact cause of the issue, the labor rates in your area, and whether any parts need to be replaced. It is advisable to get a diagnostic and repair estimate from a qualified mechanic.

9. Can a faulty O2 sensor cause the P2628 code on a Buick?

- Yes, a faulty Heated Oxygen Sensor (HO2S) can contribute to the triggering of the P2628 code due to issues with the sensor's pump current trim circuit or heater circuit.

10. How long can I safely drive my Buick with the P2628 code before getting it repaired?

- It is best to address the P2628 code as soon as possible to prevent potential damage to the vehicle and ensure optimal engine performance. Driving with this code for an extended period is not recommended.