P0642 2017 GMC Sierra Code - 5 Volt Reference 1 Circuit Low Voltage
Quick Answer
The Engine Control Module (ECM) has four (4) internal 5 Volt reference circuits (Some models have two (2) internal 5 Volt reference circuits). Common causes include Faulty Sensor on 5 Volt circuit, Sensor on 5 Volt circuit harness is open or shorted, Sensor on 5 Volt 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
- P0642 2017 GMC Sierra indicates 5 Volt Reference 1 Circuit Low Voltage.
- Common causes
- Common causes include Faulty Sensor on 5 Volt circuit, Sensor on 5 Volt circuit harness is open or shorted, Sensor on 5 Volt 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 P0642 2017 GMC Sierra Description
What are the Possible Causes of the DTC P0642 2017 GMC Sierra?
- Faulty Sensor on 5 Volt circuit
- Sensor on 5 Volt circuit harness is open or shorted
- Sensor on 5 Volt circuit poor electrical connection
- Faulty Engine Control Module (ECM)
How to Fix the DTC P0642 2017 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.
Code Tech Notes
The 5 Volt reference 1 circuit provides 5 Volt to the following sensors: (Some models may have different sensors, please consult the factory service manual for the list of sensors for your model and year)
- Air conditioning (A/C) refrigerant pressure sensor
- Camshaft position sensor
- Engine oil pressure sensor
- Fuel pressure sensor
- Fuel rail pressure sensor
- Fuel tank pressure sensor
- Multifunction intake air sensor
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0642 2017 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.
Need more information about the P0642 2017 GMC Sierra code?
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Frequently Asked Questions about P0642 2017 GMC Sierra Code
1. What does OBDII code P0642 mean on a 2017 GMC Sierra?
Code P0642 indicates a low voltage condition in the 5-volt reference circuit 1, which is critical for proper sensor operation.
2. What are the common symptoms of code P0642 in a 2017 GMC Sierra?
Symptoms may include poor engine performance, erratic sensor readings, illuminated check engine light, and potential issues with transmission shifting or reduced power mode.
3. What causes the P0642 code in a 2017 GMC Sierra?
Common causes include a shorted or damaged sensor, wiring issues such as frayed or corroded wires, or a malfunctioning powertrain control module (PCM).
4. Can a faulty sensor trigger the P0642 code?
Yes, a shorted sensor on the 5-volt reference circuit can pull the voltage down and trigger this code.
5. How can I diagnose the P0642 code in my 2017 GMC Sierra?
Inspect the 5-volt reference circuit wiring for damage, test the sensors on the circuit for shorts, and measure the voltage at the PCM and sensors using a multimeter.
6. Is it safe to drive with the P0642 code on a 2017 GMC Sierra?
Driving with this code is not recommended as it can lead to erratic engine performance and potential damage to other components.
7. How do I fix the P0642 code on a 2017 GMC Sierra?
Repairs may involve replacing a shorted sensor, repairing damaged wiring, or, in rare cases, replacing the PCM if it’s determined to be faulty.
8. Which sensors are connected to the 5-volt reference circuit in the 2017 GMC Sierra?
Sensors such as the throttle position sensor (TPS), manifold absolute pressure (MAP) sensor, and others may share the 5-volt reference circuit.
9. Can a bad PCM cause the P0642 code?
While rare, a faulty PCM can cause the P0642 code if it fails to regulate the 5-volt reference signal properly.
10. How much does it cost to fix a P0642 code on a 2017 GMC Sierra?
Repair costs can vary widely, from $50 to $150 for a damaged sensor or wiring repair, to over $500 if the PCM needs replacement and reprogramming.
Discuss the causes and fixes for P0642 2017 GMC Sierra OBDII Code
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