AutoCodes – Buick – P2602 Buick

P2602 Buick Code - Auxiliary Coolant Pump Circuit Low

Quick Answer

The auxiliary coolant pump and cooling fan system provides a measure of prevention against fuel vaporization due to excessive engine temperatures. Common causes include Faulty Auxiliary Coolant Pump Relay, Blocked pump control passage, Faulty Auxiliary Coolant Pump. 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: P2602 Buick indicates Auxiliary Coolant Pump Circuit Low.
Common causes: Common causes include Faulty Auxiliary Coolant Pump Relay, Blocked pump control passage, Faulty Auxiliary Coolant Pump.
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 1,599

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 Jan 19, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P2602 Buick Description

The auxiliary coolant pump and cooling fan system provides a measure of prevention against fuel vaporization due to excessive engine temperatures. The Engine Control Module (ECM) commands the auxiliary or after boil coolant pump ON when the engine coolant temperature exceeds a calibrated value after engine shut down. The ECM applies ground to the coil side of the auxiliary pump relay. This energizes the coil and applies voltage directly to the pump motor through the switch side of the relay. When the auxiliary coolant pump is activated, coolant is drawn from radiator and pumped into the engine through a tee in the engine coolant inlet pipe. As the colder temperature coolant is drawn into the engine warmer coolant is expelled from the engine and back to the radiator. Removing high temperature coolant from the engine after shut down helps prevent vaporization of the fuel that remains in the fuel injectors and fuel rail during a hot soak.

OBDII Code P2602 Buick - Auxiliary Coolant Pump Circuit Low - AutoCodes.com — P2602 Buick Code - Auxiliary Coolant Pump Circuit Low

What does this mean?

What are the Possible Causes of the DTC P2602 Buick?

Faulty Auxiliary Coolant Pump Relay
Blocked pump control passage
Faulty Auxiliary Coolant Pump
Auxiliary Coolant Pump harness is open or shorted
Auxiliary Coolant Pump circuit poor electrical connection

How to Fix the DTC P2602 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 P2602 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 P2602 Buick Code

1. What are the common symptoms of OBDII code P2602 in a Buick related to the Auxiliary Coolant Pump Circuit Low?

- Common symptoms include overheating of the engine, reduced engine performance, and the coolant temperature gauge reading higher than normal.

2. What are some possible causes of OBDII code P2602 in a Buick indicating an Auxiliary Coolant Pump Circuit Low?

- Possible causes include a faulty auxiliary coolant pump, damaged wiring or connectors in the circuit, low coolant levels, or a malfunctioning coolant temperature sensor.

3. How can I diagnose the OBDII code P2602 in my Buick for the Auxiliary Coolant Pump Circuit Low?

- Diagnosis involves checking the auxiliary coolant pump for proper operation, inspecting the wiring and connectors for any damage, testing the coolant temperature sensor, and verifying coolant levels.

4. What are the potential risks of driving with the OBDII code P2602 in a Buick related to the Auxiliary Coolant Pump Circuit Low?

- Driving with this code can lead to engine overheating, which may cause severe damage to the engine components and result in costly repairs if not addressed promptly.

5. Can I reset the OBDII code P2602 in my Buick indicating an Auxiliary Coolant Pump Circuit Low without fixing the underlying issue?

- While you can clear the code with a diagnostic tool, it is not recommended to do so without addressing the root cause, as the problem may persist and potentially lead to more significant issues.

6. Are there any simple repair tips for fixing OBDII code P2602 in a Buick due to an Auxiliary Coolant Pump Circuit Low?

- Start by checking the coolant levels, inspecting the pump and circuit for visible damage, and ensuring all connections are secure. If no issues are found, consider seeking professional help for a thorough diagnosis.

7. How much does it typically cost to repair OBDII code P2602 in a Buick associated with the Auxiliary Coolant Pump Circuit Low?

- The cost of repair can vary depending on the exact cause of the issue, but it may range from around $100 for a simple fix like replacing a sensor to several hundred dollars for more complex repairs involving the pump or wiring.

8. Can a DIY enthusiast with some automotive knowledge fix OBDII code P2602 in a Buick related to the Auxiliary Coolant Pump Circuit Low?

- Depending on the specific cause, some DIY enthusiasts may be able to address simpler issues like replacing a sensor or checking connections. However, more complex repairs involving the pump or wiring may require professional expertise.

9. How urgent is it to address OBDII code P2602 in a Buick indicating an Auxiliary Coolant Pump Circuit Low?

- It is essential to address this issue promptly to prevent engine overheating and potential damage. Ignoring the problem can lead to more severe consequences and higher repair costs in the long run.

10. Is it possible for the OBDII code P2602 in a Buick related to the Auxiliary Coolant Pump Circuit Low to reoccur after repairs?

- If the underlying cause of the code is not properly addressed during repairs, it is possible for the issue to reoccur. Ensuring a thorough diagnosis and complete repair can help prevent the problem from coming back.