P1478 2018 Chevrolet Silverado Code - Particulate Matter Sensor Temperature Circuit High Voltage
Quick Answer
The Particulate Matter (PM) sensor monitors the amount of the particulates (soot) in the diesel exhaust gas exiting the tailpipe. Common causes include Faulty Exhaust Particulate Matter Sensor, Exhaust Particulate Matter Sensor harness is open or shorted, Exhaust Particulate Matter 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
- P1478 2018 Chevrolet Silverado indicates Particulate Matter Sensor Temperature Circuit High Voltage.
- Common causes
- Common causes include Faulty Exhaust Particulate Matter Sensor, Exhaust Particulate Matter Sensor harness is open or shorted, Exhaust Particulate Matter 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.
Code P1478 2018 Chevrolet Silverado Description
The operation of the PM Sensor is based on the electrical conductivity characteristic of the diesel particulate. As the exhaust gas flows over the sensing element, soot is absorbed in the combs between the electrodes, eventually creating a conductive path. When the path is formed, it generates a current based on the voltage being applied to the element. The measurement process continues until a preset current value is reached. To avoid misleading readings, the sensor performs a regeneration where the soot is cleaned off by heating up the element before the measurement phase begins. The amount of regenerations is based on vehicle strategy; when the calibrated number of regenerations is reached, the cumulative current readings are used to determine the amount of soot concentration in the exhaust gas which in turn determines the collection efficiency of the Diesel Particulate Filter (DPF).
The Diagnostic Trouble Code (DTC) will be set when the particular matter sensor control unit detects a fault in the particulate matter sensor circuitry.
What are the Possible Causes of the DTC P1478 2018 Chevrolet Silverado?
- Faulty Exhaust Particulate Matter Sensor
- Exhaust Particulate Matter Sensor harness is open or shorted
- Exhaust Particulate Matter Sensor circuit poor electrical connection
How to Fix the DTC P1478 2018 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 P1478 2018 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.
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Frequently Asked Questions about P1478 2018 Chevrolet Silverado Code
1. What does the OBDII code P1478 mean on a 2018 Chevrolet Silverado?
P1478 indicates a "Particulate Matter Sensor Temperature Circuit High Voltage," meaning the voltage in the particulate matter sensor's temperature circuit is higher than the expected range.
2. What are the symptoms of code P1478 in a 2018 Chevrolet Silverado?
Common symptoms include the check engine light turning on, reduced fuel efficiency, possible performance issues, and in some cases, increased emissions.
3. What causes the P1478 code to appear in my Silverado?
The code can be caused by a faulty particulate matter sensor, damaged wiring or connectors, a short circuit, or an issue with the engine control module (ECM).
4. Can I drive my 2018 Chevrolet Silverado with code P1478?
While the vehicle might still be drivable, it’s not recommended to ignore the code as it could lead to further damage to the emissions system or reduced engine performance.
5. How do I diagnose the P1478 code?
Start by inspecting the wiring and connectors for damage or corrosion. Use a multimeter to check sensor voltage levels and scan the ECM for related codes that may indicate a deeper issue.
6. How do I fix the P1478 code on a 2018 Chevrolet Silverado?
Repairs may include replacing the particulate matter sensor, repairing or replacing damaged wiring, or reprogramming/updating the ECM.
7. How much does it cost to repair a P1478 code on a Silverado?
The repair cost depends on the specific issue, but replacing a particulate matter sensor typically costs $200–$500, including parts and labor.
8. Can a dirty particulate filter cause the P1478 code?
While a clogged diesel particulate filter (DPF) doesn’t directly cause this code, it can increase stress on the sensor and should be checked if the code persists.
9. Is the P1478 code covered under warranty for a 2018 Chevrolet Silverado?
If your vehicle is still under the emissions warranty, the repair may be covered. Check with your dealer for confirmation.
10. How do I prevent the P1478 code from reoccurring?
Regular maintenance, including inspecting the particulate matter sensor and ensuring the DPF system is functioning properly, can help prevent this code from reoccurring.
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