P1478 2016 GMC Sierra 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 2016 GMC Sierra 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 2016 GMC Sierra 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 2016 GMC Sierra?
- 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 2016 GMC Sierra?
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 2016 GMC Sierra 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 2016 GMC Sierra Code
1. What does the OBDII code P1478 mean on a 2016 GMC Sierra?
P1478 indicates a "Particulate Matter Sensor Temperature Circuit High Voltage," meaning the engine control module (ECM) has detected a high voltage signal from the particulate matter sensor temperature circuit.
2. What are the symptoms of code P1478 in a 2016 GMC Sierra?
Common symptoms include an illuminated check engine light, reduced engine performance, poor fuel efficiency, and potential issues with the diesel particulate filter (DPF) regeneration process.
3. What causes the P1478 code to appear on a 2016 GMC Sierra?
Possible causes include a faulty particulate matter sensor, damaged wiring or connectors in the temperature circuit, a short to voltage, or a malfunctioning ECM.
4. Can I still drive my 2016 GMC Sierra with the P1478 code active?
While the vehicle may still be drivable, continuing to operate it with this code can lead to further damage to the emissions system or reduced performance. It's best to address the issue promptly.
5. How is the P1478 code diagnosed?
A mechanic will use a scan tool to confirm the code, visually inspect the wiring and connectors, test the particulate matter sensor, and check for continuity or voltage issues in the circuit.
6. What repairs can fix the P1478 code in a 2016 GMC Sierra?
Repairs may include replacing the particulate matter sensor, repairing damaged wiring or connectors, or reprogramming or replacing the ECM if necessary.
7. How much does it cost to repair the P1478 code in a 2016 GMC Sierra?
Repair costs vary but typically range from $200 to $600, depending on whether the particulate matter sensor, wiring, or ECM needs to be repaired or replaced.
8. Can a faulty particulate matter sensor cause other issues in the 2016 GMC Sierra?
Yes, a faulty sensor can disrupt the DPF regeneration process, leading to excessive soot buildup and potential damage to the emissions system.
9. Is the P1478 code covered under warranty for a 2016 GMC Sierra?
If your vehicle is still under the emissions warranty, the repair may be covered. Check with your dealership for details.
10. How can I prevent the P1478 code from occurring again?
Regular maintenance, inspecting wiring for damage, and addressing check engine light issues promptly can help prevent this code from recurring.
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