AutoCodes – Buick – P1194 Buick

P1194 Buick Code - O2 Low Reference Circuit High Voltage (NOx Sensor 1)

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, Nitrogen Oxides Sensor harness is open or shorted, Nitrogen Oxides Sensor 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: P1194 Buick indicates O2 Low Reference Circuit High Voltage (NOx Sensor 1).
Common causes: Common causes include Faulty Nitrogen Oxides (NOx) Sensor, Nitrogen Oxides Sensor harness is open or shorted, Nitrogen Oxides Sensor 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 506

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 29, 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 P1194 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 P1194 Buick - O2 Low Reference Circuit High Voltage (NOx Sensor 1) - AutoCodes.com — P1194 Buick Code - O2 Low Reference Circuit High Voltage (NOx Sensor 1)

What does this mean?

What are the Possible Causes of the DTC P1194 Buick?

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

How to Fix the DTC P1194 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 P1194 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.

Need more information about the P1194 Buick code?

Need more information on how to fix the P1194 Buick code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P1194 Buick code diagnosed by a professional: Find a repair shop in your area

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 P1194 Buick Code

1. What are the common symptoms of OBDII code P1194 in a Buick related to the O2 Low Reference Circuit High Voltage (NOx Sensor 1)?

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

2. What are the potential causes of OBDII code P1194 in a Buick?

- Possible causes include a faulty NOx sensor, wiring issues in the O2 sensor circuit, sensor connector problems, or issues with the engine control module (ECM).

3. How can I diagnose OBDII code P1194 in a Buick?

- Diagnosis involves using an OBDII scanner to retrieve the specific fault code, checking the NOx sensor and its connections, and inspecting the wiring for any damage or loose connections.

4. Can driving with OBDII code P1194 in a Buick cause further damage?

- Continuing to drive with this code may lead to decreased engine efficiency and potential damage to other components, so it is advisable to address the issue promptly.

5. What are some repair tips for fixing OBDII code P1194 in a Buick?

- Repair tips include checking and replacing the NOx sensor if necessary, repairing any damaged wiring, ensuring proper sensor connections, and clearing the fault code with an OBDII scanner after repairs.

6. Is it safe to reset the check engine light after addressing OBDII code P1194 in a Buick?

- Yes, it is safe to reset the check engine light using an OBDII scanner after resolving the underlying issue causing code P1194.

7. How much does it typically cost to repair OBDII code P1194 in a Buick?

- Repair costs can vary depending on the specific issue, but they may range from $100 to $400, including parts and labor.

8. Can a DIY enthusiast fix OBDII code P1194 in a Buick themselves?

- Depending on their skill level and access to tools, a DIY enthusiast may be able to address this code by following repair guides and using an OBDII scanner for diagnosis and code clearing.

9. Are there any recalls or technical service bulletins related to OBDII code P1194 in Buick vehicles?

- It is recommended to check with the manufacturer or a qualified mechanic to see if there are any relevant recalls or technical service bulletins addressing this specific OBDII code in Buick vehicles.

10. How often does OBDII code P1194 related to the O2 Low Reference Circuit High Voltage (NOx Sensor 1) occur in Buick vehicles?

- While the frequency may vary, this code can occur in Buick vehicles equipped with NOx sensors and OBDII systems, especially in older models or those with high mileage.