AutoCodes – Buick – P1641 Buick

P1641 Buick Code - Cooling Fan Relay 1 Control Circuit

Quick Answer

Ignition voltage is supplied to the Cooling Fan relay coil. Common causes include Faulty Cooling Fan Relay, Cooling Fan Relay harness is open or shorted, Cooling Fan Relay circuit poor electrical component. 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: P1641 Buick indicates Cooling Fan Relay 1 Control Circuit.
Common causes: Common causes include Faulty Cooling Fan Relay, Cooling Fan Relay harness is open or shorted, Cooling Fan Relay circuit poor electrical component.
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.

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Code Popularity 7,357

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Sep 04, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1641 Buick Description

Ignition voltage is supplied to the Cooling Fan relay coil. The Powertrain Control Module (PCM) controls the relay by grounding the control circuit via an internal switch called a driver. The primary function of the driver is to supply the ground for the component being controlled. Each driver has a fault line which is monitored by the PCM. When the PCM is commanding a component ON, the voltage of the control circuit should be low (near 0 volts). When the PCM is commanding the control circuit to a component OFF, the voltage potential of the circuit should be high (near battery voltage). If the fault detection circuit senses a voltage other than what is expected, the fault line status will change causing the code to set.
The relay is used to control the high current flow to the cooling fan motors. This allows the PCM driver to only have to handle the relatively low current used by the relay.

OBDII Code P1641 Buick - Cooling Fan Relay 1 Control Circuit - AutoCodes.com — P1641 Buick Code - Cooling Fan Relay 1 Control Circuit

What does this mean?

What are the Possible Causes of the DTC P1641 Buick?

Faulty Cooling Fan Relay
Cooling Fan Relay harness is open or shorted
Cooling Fan Relay circuit poor electrical component

How to Fix the DTC P1641 Buick?

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 P1641 Buick 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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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P1641 Buick Code

1. What are the common symptoms of OBDII code P1641 in a Buick related to the Cooling Fan Relay 1 Control Circuit?

- Common symptoms include the cooling fan not operating properly, engine overheating, and the check engine light being illuminated.

2. What are some possible causes of OBDII code P1641 in a Buick related to the Cooling Fan Relay 1 Control Circuit?

- Possible causes include a faulty cooling fan relay, wiring issues, a malfunctioning cooling fan motor, or a problem with the engine control module.

3. How can I diagnose the issue causing OBDII code P1641 in my Buick related to the Cooling Fan Relay 1 Control Circuit?

- You can diagnose the issue by checking the cooling fan relay, inspecting the wiring for any damage, testing the cooling fan motor, and scanning the engine control module for any related fault codes.

4. Can I continue to drive my Buick with OBDII code P1641 related to the Cooling Fan Relay 1 Control Circuit?

- It is not recommended to drive your Buick with this code as it can lead to engine overheating and potential damage. It is best to address the issue promptly.

5. How can I repair OBDII code P1641 in my Buick related to the Cooling Fan Relay 1 Control Circuit?

- Repairing the issue may involve replacing the cooling fan relay, repairing any damaged wiring, replacing the cooling fan motor if necessary, or reprogramming the engine control module.

6. Are there any DIY tips for addressing OBDII code P1641 in a Buick related to the Cooling Fan Relay 1 Control Circuit?

- DIY tips include checking and cleaning electrical connections, inspecting for any visible damage to wiring, and ensuring the cooling fan blades can spin freely.

7. Will resetting the check engine light resolve OBDII code P1641 in a Buick related to the Cooling Fan Relay 1 Control Circuit?

- Resetting the check engine light will not fix the underlying issue causing the code. It is important to diagnose and repair the problem to prevent further issues.

8. Is it necessary to replace the cooling fan assembly when dealing with OBDII code P1641 in a Buick related to the Cooling Fan Relay 1 Control Circuit?

- Not necessarily. The issue may be isolated to the relay, wiring, or control module. However, if the cooling fan motor is faulty, it may require replacement.

9. How long does it typically take to repair OBDII code P1641 in a Buick related to the Cooling Fan Relay 1 Control Circuit?

- The repair time can vary depending on the exact cause of the issue. It may take anywhere from 1-3 hours to diagnose and repair the problem.

10. Can extreme weather conditions impact the occurrence of OBDII code P1641 in a Buick related to the Cooling Fan Relay 1 Control Circuit?

- Yes, extreme heat can put more strain on the cooling system components, potentially leading to issues with the cooling fan relay and causing the code to be triggered.