AutoCodes – Chevrolet – P1194 2014 Chevrolet Silverado

P1194 2014 Chevrolet Silverado 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 2014 Chevrolet Silverado 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.

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Code Popularity 228

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 Mar 24, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1194 2014 Chevrolet Silverado 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 2014 Chevrolet Silverado - O2 Low Reference Circuit High Voltage (NOx Sensor 1) - AutoCodes.com — P1194 2014 Chevrolet Silverado Code - O2 Low Reference Circuit High Voltage (NOx Sensor 1)

What does this mean?

What are the Possible Causes of the DTC P1194 2014 Chevrolet Silverado?

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 2014 Chevrolet Silverado?

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 2014 Chevrolet Silverado 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 2014 Chevrolet Silverado code?

Need more information on how to fix the P1194 2014 Chevrolet Silverado code? Get Access to Factory Service Manuals

Need Help with the Code?

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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 P1194 2014 Chevrolet Silverado Code

What does the OBDII code P1194 mean for a 2014 Chevrolet Silverado?

Code P1194 indicates an issue with the "O2 Low Reference Circuit High Voltage" related to NOx Sensor 1, which monitors nitrogen oxide levels in the exhaust system.

What are common symptoms of code P1194 in a 2014 Chevrolet Silverado?

Symptoms include an illuminated check engine light, reduced fuel efficiency, poor engine performance, and potentially increased emissions.

What causes the P1194 code to appear?

Common causes include a faulty NOx sensor 1, damaged wiring or connectors in the O2 low reference circuit, or excessive voltage in the circuit due to electrical issues.

Can a faulty NOx sensor trigger the P1194 code?

Yes, a malfunctioning NOx sensor 1 can cause this code by sending incorrect voltage signals to the vehicle's computer.

How can I diagnose the P1194 code?

Start by visually inspecting the NOx sensor and its wiring for damage or corrosion. Use a scan tool to monitor sensor readings and check for proper voltage levels in the O2 low reference circuit.

Is the P1194 code serious?

While your vehicle may still run, this code can result in higher emissions and reduced engine performance. Addressing it promptly is recommended to avoid further damage.

Can the P1194 code affect fuel economy?

Yes, unresolved issues with the NOx sensor can lead to inefficient combustion, reducing fuel economy.

How do you fix the P1194 code?

Repairs may involve replacing the NOx sensor 1, repairing or replacing damaged wiring, or addressing voltage irregularities in the low reference circuit.

Can the P1194 code be caused by a software issue?

While rare, outdated or corrupted engine control module (ECM) software can occasionally contribute to this code. A software update might resolve the issue.

Should I clear the P1194 code after repairs?

Yes, once repairs are complete, clear the code using a scan tool and test drive the vehicle to ensure the issue does not return.