AutoCodes – GMC – P2602 GMC

P2602 GMC 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 GMC 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 1,497

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

What does this mean?

What are the Possible Causes of the DTC P2602 GMC?

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 GMC?

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 GMC 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 GMC Code

1. What are the common symptoms of OBDII code P2602 GMC (Auxiliary Coolant Pump Circuit Low)?

The common symptoms include engine overheating, poor heater performance, and a potential decrease in fuel efficiency.

2. What are the possible causes of OBDII code P2602 GMC?

Possible causes include a faulty auxiliary coolant pump, damaged wiring or connectors in the coolant pump circuit, low coolant levels, or a malfunctioning engine control module.

3. How can I diagnose the cause of OBDII code P2602 GMC?

You can diagnose the code by checking the coolant pump for proper operation, inspecting the wiring and connectors for any damage, testing the coolant level, and using a scan tool to read live data and monitor the coolant pump circuit.

4. Can I continue driving with OBDII code P2602 GMC active?

It is not recommended to continue driving with this code active, as it can lead to engine overheating and potential damage. It is best to address the issue as soon as possible.

5. How can I repair OBDII code P2602 GMC?

Repairing the code involves addressing the root cause, which may include replacing the faulty auxiliary coolant pump, repairing damaged wiring or connectors, ensuring proper coolant levels, or reprogramming the engine control module if necessary.

6. Will resetting the trouble codes make OBDII code P2602 GMC disappear?

Resetting the trouble codes may temporarily clear the code, but if the underlying issue is not addressed, the code is likely to reappear once the problem is detected again by the vehicle's system.

7. Can a DIYer fix OBDII code P2602 GMC?

Depending on your level of automotive repair knowledge and experience, you may be able to address this code yourself by following diagnostic steps, checking components, and making necessary repairs. However, if you are unsure, it is recommended to seek professional help.

8. How much does it cost to repair OBDII code P2602 GMC?

The cost of repairing this code can vary based on the specific cause of the issue, parts needed for replacement, and labor costs. It is advisable to obtain quotes from automotive professionals to get an accurate estimate.

9. Is OBDII code P2602 GMC a serious issue?

OBDII code P2602 GMC should be addressed promptly to prevent potential engine damage due to overheating. While it may not cause an immediate breakdown, ignoring the issue can lead to more significant problems over time.

10. Can extreme weather conditions affect OBDII code P2602 GMC?

Extreme weather conditions, such as very high or very low temperatures, can potentially exacerbate issues related to the auxiliary coolant pump circuit, leading to the activation of OBDII code P2602 GMC.