P0643 2017 GMC Sierra Code - 5 Volt Reference 1 Circuit High 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
- P0643 2017 GMC Sierra indicates 5 Volt Reference 1 Circuit High 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 P0643 2017 GMC Sierra Description
What are the Possible Causes of the DTC P0643 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 P0643 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 P0643 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 P0643 2017 GMC Sierra code?
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Frequently Asked Questions about P0643 2017 GMC Sierra Code
1. What does the OBDII code P0643 mean on a 2017 GMC Sierra?
P0643 indicates a high voltage issue in the 5-volt reference 1 circuit, which is a critical voltage supply for various engine sensors.
2. What are the symptoms of code P0643 in a 2017 GMC Sierra?
Symptoms may include a check engine light, poor engine performance, erratic sensor readings, hard starting, or stalling.
3. What causes the P0643 code to appear on a 2017 GMC Sierra?
Common causes include a shorted or open 5-volt reference circuit, a faulty sensor, a damaged wiring harness, or a malfunctioning engine control module (ECM).
4. How do you diagnose the P0643 code on a 2017 GMC Sierra?
Diagnosis involves checking the 5-volt reference circuit for short circuits, inspecting wiring and connectors, testing sensors for faults, and verifying ECM operation.
5. Can a faulty sensor trigger the P0643 code on a 2017 GMC Sierra?
Yes, a faulty sensor that uses the 5-volt reference circuit can cause the voltage to exceed the expected range, triggering the code.
6. Is it safe to drive a 2017 GMC Sierra with the P0643 code?
Driving with this code is not recommended, as it can lead to poor performance or potential engine stalling, which could create unsafe driving conditions.
7. How do you fix the P0643 code on a 2017 GMC Sierra?
Repairs may include replacing a damaged sensor, repairing or replacing faulty wiring, or in rare cases, replacing the ECM.
8. Can a dead battery cause the P0643 code in a 2017 GMC Sierra?
While unlikely, electrical issues such as voltage spikes during jump-starting could potentially damage circuits and cause the code.
9. How much does it cost to fix the P0643 code on a 2017 GMC Sierra?
Repair costs vary depending on the issue, but replacing a sensor or repairing wiring typically costs between $100 and $500. ECM replacement can be more expensive.
10. Do I need to clear the P0643 code after repairs on a 2017 GMC Sierra?
Yes, after completing the repairs, you should clear the code using an OBDII scanner and verify that it does not return.
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