AutoCodes – Generic – P1641

P1641 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 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 52,352

How popular is this code, among other codes? Medium

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

What does this mean?

What are the Possible Causes of the DTC P1641?

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?

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 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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Information for Specific Makes

P1641 Buick — Cooling Fan Relay 1 Control Circuit
P1641 Cadillac — Cooling Fan Relay 1 Control Circuit
P1641 Chevrolet — Cooling Fan Relay 1 Control Circuit
P1641 Dodge — Cabin Heater 1
P1641 Ford — Fuel Pump Driver Module Fault Conditions
P1641 GMC — Cooling Fan Relay 1 Control Circuit
P1641 Honda — ACTTRQ Motor Torque Signal Circuit High Input
P1641 Hyundai — VI Motor Open / Short Coil 2
P1641 Jaguar — Fuel Pump Relay 1 Malfunction
P1641 Lincoln — Fuel Pump Driver Module Fault Conditions
P1641 Mazda — Fuel Pump Circuit Malfunction
P1641 Mercedes-Benz — Engine Control Module TP Signal
P1641 Mercury — Fuel Pump Driver Module Fault Conditions
P1641 Pontiac — Cooling Fan Relay 1 Control Circuit
P1641 Saab — Fuel Pump Relay No Voltage To Fuel Pump / Oxygen Sensor Heater
P1641 Saturn — Cooling Fan Relay 1 Control Circuit

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 Code

1. What are common symptoms of OBDII code P1641 (Cooling Fan Relay 1 Control Circuit)?

- Common symptoms include overheating of the engine, erratic cooling fan operation, and illumination of the check engine light.

2. What are possible causes of OBDII code P1641?

- Possible causes include a faulty cooling fan relay, damaged wiring or connectors in the cooling fan circuit, or a malfunctioning engine coolant temperature sensor.

3. How can I diagnose the cause of OBDII code P1641?

- To diagnose this code, you can use a scan tool to check for any other related codes, inspect the cooling fan relay and its connections, test the engine coolant temperature sensor, and check for any damaged wiring in the circuit.

4. Can I still drive my vehicle with OBDII code P1641?

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

5. How do I repair OBDII code P1641?

- Repair options may include replacing the cooling fan relay, repairing or replacing damaged wiring or connectors, and testing or replacing the engine coolant temperature sensor.

6. Will resetting the check engine light resolve OBDII code P1641?

- Resetting the check engine light may temporarily turn it off, but the underlying issue causing the code will still need to be diagnosed and repaired to prevent it from returning.

7. Can a DIY enthusiast fix OBDII code P1641?

- Depending on your level of automotive repair experience, you may be able to address this code yourself by following repair guides and using basic tools. However, if you are unsure, it's best to seek professional help.

8. Is OBDII code P1641 specific to certain vehicle makes and models?

- This code can be found in various vehicle makes and models, particularly those equipped with OBDII systems and cooling fan circuits controlled by relays.

9. Are there any preventive maintenance tips to avoid OBDII code P1641?

- Regularly inspecting and maintaining the cooling system, including the cooling fan relay, wiring, and sensors, can help prevent issues that may trigger this code.

10. How long does it typically take to repair OBDII code P1641?

- The repair time can vary depending on the exact cause of the code and the availability of parts. It may take anywhere from 30 minutes to a few hours to diagnose and repair the issue.