P0642 2015 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 2015 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 2015 GMC Sierra Description
What are the Possible Causes of the DTC P0642 2015 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 2015 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 2015 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 2015 GMC Sierra code?
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Frequently Asked Questions about P0642 2015 GMC Sierra Code
1. What does the OBDII code P0642 mean on a 2015 GMC Sierra?
P0642 indicates a low voltage issue in the 5-volt reference circuit 1, which supplies power to various engine sensors.
2. What are the common symptoms of code P0642 in a 2015 GMC Sierra?
Symptoms may include poor engine performance, reduced fuel efficiency, erratic sensor readings, and possible activation of the check engine light.
3. What causes the P0642 code to appear in a 2015 GMC Sierra?
Common causes include a short circuit in the 5-volt reference wiring, a faulty sensor, a malfunctioning engine control module (ECM), or damaged connectors.
4. Can I drive my 2015 GMC Sierra with code P0642?
Driving with this code is not recommended as it can lead to improper engine performance and potential damage to other components.
5. How do I diagnose the P0642 code on my 2015 GMC Sierra?
Start by inspecting the 5-volt reference wiring and connectors for damage, check for any faulty sensors connected to the circuit, and use a multimeter to verify voltage levels.
6. Which sensors rely on the 5-volt reference circuit in a 2015 GMC Sierra?
Sensors such as the throttle position sensor (TPS), manifold absolute pressure (MAP) sensor, and crankshaft position sensor may use the 5-volt reference circuit.
7. Can a damaged sensor cause the P0642 code on a 2015 GMC Sierra?
Yes, a shorted or faulty sensor connected to the 5-volt reference circuit can cause the voltage to drop and trigger the code.
8. How can I fix the P0642 code on my 2015 GMC Sierra?
Repairs may involve replacing a faulty sensor, repairing damaged wiring or connectors, or in rare cases, replacing the ECM if it is defective.
9. How much does it cost to fix the P0642 code on a 2015 GMC Sierra?
Repair costs vary, but replacing a sensor may cost $100–$300, while more extensive repairs involving wiring or the ECM can exceed $500.
10. Can a faulty ECM cause the P0642 code on a 2015 GMC Sierra?
While rare, a malfunctioning ECM can cause this code if it fails to properly regulate the 5-volt reference circuit.
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