P1194 2018 GMC Sierra Code - O2 Low Reference Circuit High Voltage (NOx Sensor 1)
Quick Answer
The P1194 diagnostic trouble code (DTC) for a 2018 GMC Sierra indicates an issue with the O2 Low Reference Circuit High Voltage related to the NOx Sensor 1. Common causes include Faulty NOx sensor, Wiring or connector issues in the O2 sensor circuit, ECM software malfunction. 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 2018 GMC Sierra indicates O2 Low Reference Circuit High Voltage (NOx Sensor 1).
- Common causes
- Common causes include Faulty NOx sensor, Wiring or connector issues in the O2 sensor circuit, ECM software malfunction.
- 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 P1194 2018 GMC Sierra Description
The P1194 diagnostic trouble code (DTC) for a 2018 GMC Sierra indicates an issue with the O2 Low Reference Circuit High Voltage related to the NOx Sensor 1. This code specifically points to a problem in the oxygen sensor circuit that measures the amount of oxygen in the exhaust gases. The NOx sensor is responsible for monitoring the levels of nitrogen oxide (NOx) in the exhaust system, which is crucial for emissions control and ensuring compliance with environmental regulations.
Common Causes of P1194 2018 GMC Sierra
- Faulty NOx sensor
- Wiring or connector issues in the O2 sensor circuit
- ECM software malfunction
- Exhaust system leaks or damage
- Contaminated exhaust gases affecting sensor readings
Symptoms of P1194 2018 GMC Sierra
- Decreased fuel efficiency
- Rough idling or stalling
- Hesitation or lack of power during acceleration
- Increased emissions
- Check Engine Light illuminated
How to Fix P1194 2018 GMC Sierra
- Begin by conducting a thorough inspection of the NOx sensor and its wiring for any visible damage or corrosion.
- Test the sensor's output voltage using a multimeter to determine if it is within the specified range.
- Check the wiring harness and connectors for any loose connections or shorts that may be affecting the sensor's operation.
- If necessary, replace the NOx sensor with a new, OEM-quality part to ensure accurate readings and proper functionality.
- Clear the DTC from the ECM's memory and perform a road test to verify that the issue has been resolved.
Cost to Fix P1194 2018 GMC Sierra
The typical repair costs for addressing a P1194 code on a 2018 GMC Sierra can range from $200 to $500, including parts and labor. However, it's important to note that actual costs may vary depending on the specific diagnosis time, labor rates, and the location of the repair shop. Rates at dealerships or in metropolitan areas may be higher, while independent shops often offer more competitive pricing. It's recommended to obtain quotes from multiple sources to get a more accurate estimate for this repair.
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Frequently Asked Questions about P1194 2018 GMC Sierra Code
1. What does the OBDII code P1194 mean on a 2018 GMC Sierra?
P1194 indicates an issue with the O2 Low Reference Circuit High Voltage for NOx Sensor 1, meaning the sensor is detecting higher-than-expected voltage in the reference circuit.
2. What are the common symptoms of the P1194 code in a 2018 GMC Sierra?
Symptoms may include the check engine light turning on, reduced fuel efficiency, poor engine performance, or the vehicle entering limp mode.
3. What causes the P1194 code in a GMC Sierra?
Common causes include a faulty NOx sensor, damaged wiring or connectors, corrosion in the circuit, or a malfunctioning ECM.
4. Can a faulty NOx sensor cause the P1194 code?
Yes, a malfunctioning NOx sensor is a primary cause of this code, as it may send incorrect voltage signals to the ECM.
5. How do I diagnose the P1194 code in a 2018 GMC Sierra?
Diagnose by using a scan tool to confirm the code, inspecting the wiring and connectors for damage or corrosion, and testing the NOx sensor and reference circuit voltage.
6. Is it safe to drive with a P1194 code on my 2018 GMC Sierra?
While the vehicle may still be drivable, it can suffer from reduced performance or fuel efficiency, and ignoring the issue could lead to further damage.
7. How do I fix the P1194 code on a GMC Sierra?
Repairs may involve replacing the NOx sensor, repairing or replacing damaged wiring, cleaning corroded connectors, or reprogramming the ECM if necessary.
8. What tools are needed to fix the P1194 code?
You’ll need an OBDII scan tool, a multimeter for electrical testing, and possibly basic hand tools to remove and replace the NOx sensor.
9. How much does it cost to repair the P1194 code on a 2018 GMC Sierra?
Repair costs vary, but replacing a NOx sensor can cost between $300 and $800, depending on labor and parts availability.
10. Can a software update fix the P1194 code?
In some cases, an ECM software update may resolve the issue if the problem is related to a programming error or calibration issue.
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