P1642 GMC Code - Fan Control Relay 2 and 3 Control Circuit
Quick Answer
The P1642 GMC code indicates a problem with the Fan Control Relay 2 and 3 Control Circuit in the vehicle. Common causes include Faulty Fan Control Relay: The most common cause of the P1642 code is a malfunctioning fan control relay, which can prevent the cooling fans from operating as intended, Electrical Wiring Issues: Damaged or corroded wiring connections to the fan control relays can disrupt the circuit and trigger the code, Blown Fuse: A blown fuse in the cooling fan circuit can also cause the fan control relay to fail and trigger the code. 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
- P1642 GMC indicates Fan Control Relay 2 and 3 Control Circuit.
- Common causes
- Common causes include Faulty Fan Control Relay: The most common cause of the P1642 code is a malfunctioning fan control relay, which can prevent the cooling fans from operating as intended, Electrical Wiring Issues: Damaged or corroded wiring connections to the fan control relays can disrupt the circuit and trigger the code, Blown Fuse: A blown fuse in the cooling fan circuit can also cause the fan control relay to fail and trigger the code.
- 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.
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.
Code P1642 GMC Description
The P1642 GMC code indicates a problem with the Fan Control Relay 2 and 3 Control Circuit in the vehicle. The fan control relays are responsible for regulating the operation of the cooling fans in the engine. When these relays malfunction, it can lead to issues with the cooling system, potentially causing the engine to overheat.
Common Causes of P1642 GMC
- Faulty Fan Control Relay: The most common cause of the P1642 code is a malfunctioning fan control relay, which can prevent the cooling fans from operating as intended.
- Electrical Wiring Issues: Damaged or corroded wiring connections to the fan control relays can disrupt the circuit and trigger the code.
- Blown Fuse: A blown fuse in the cooling fan circuit can also cause the fan control relay to fail and trigger the code.
- Defective Cooling Fan Motor: A faulty cooling fan motor can put additional strain on the fan control relays, leading to their malfunction.
- ECM/PCM Failure: In rare cases, a failure in the engine control module (ECM) or powertrain control module (PCM) can cause issues with the fan control relays and trigger the code.
Symptoms of P1642 GMC
- Check Engine Light: The most common symptom associated with the P1642 code is the illumination of the check engine light on the dashboard.
- Engine Overheating: If the cooling fans fail to operate properly, the engine may overheat, leading to temperature spikes and potential damage.
- Poor Air Conditioning Performance: Malfunctioning fan control relays can also impact the performance of the air conditioning system, causing reduced cooling efficiency.
- High Engine Temperature Gauge Reading: The temperature gauge on the dashboard may show higher than normal temperatures if the cooling fans are not functioning correctly.
- Loud Fan Noise: In some cases, a malfunctioning fan control relay may cause the cooling fans to operate at high speeds, resulting in loud noise during operation.
How to Fix P1642 GMC
- Diagnose the Issue: Use a diagnostic scanner to retrieve the trouble codes and pinpoint the exact cause of the problem.
- Inspect Fan Control Relays: Check the fan control relays for any signs of damage or wear, and replace them if necessary.
- Check Wiring Connections: Inspect the electrical wiring connections to the fan control relays for any damage or corrosion, and repair or replace as needed.
- Test Cooling Fan Operation: Verify that the cooling fans are operating correctly after replacing the relays and repairing any wiring issues.
- Clear Codes and Test Drive: Clear the trouble codes from the vehicle's computer memory, and test drive the vehicle to ensure that the issue has been resolved.
Cost to Fix P1642 GMC
The typical repair costs for addressing the P1642 GMC code can vary depending on the specific cause of the issue. On average, the cost of replacing fan control relays and addressing wiring issues can range from $150 to $400, including parts and labor. However, the total cost may increase if additional components such as cooling fan motors or ECM/PCM need to be replaced. It's important to note that diagnosis time and labor rates at auto repair shops can vary, so it's recommended to check with local shops for a more accurate estimate.
Need more information about the P1642 GMC code?
Need more information on how to fix the P1642 GMC code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the P1642 GMC code diagnosed by a professional: Find a repair shop in your area
Frequently Asked Questions about P1642 GMC Code
No Frequently Asked Questions about P1642 GMC Code found.
Discuss the causes and fixes for P1642 GMC OBDII Code
Code P1642 GMC comments
No comments found for this page.
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.