AutoCodes – GMC – P26A3 GMC

P26A3 GMC Code - Engine Coolant Bypass Valve Range/Performance

Quick Answer

The passenger compartment heater coolant control valve regulates the engine coolant flow into the cabin heater loop depending on engine coolant temperature and ambient temperature conditions. Common causes include Faulty Engine Coolant Bypass Valve, Engine Coolant Bypass Valve harness is open or shorted, Engine Coolant Bypass Valve circuit poor electrical connection. 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: P26A3 GMC indicates Engine Coolant Bypass Valve Range/Performance.
Common causes: Common causes include Faulty Engine Coolant Bypass Valve, Engine Coolant Bypass Valve harness is open or shorted, Engine Coolant Bypass Valve circuit poor electrical connection.
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 1,292

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 03, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P26A3 GMC Description

The passenger compartment heater coolant control valve regulates the engine coolant flow into the cabin heater loop depending on engine coolant temperature and ambient temperature conditions. The passenger compartment heater coolant control valve has two positions: ByPass or Link. In the ByPass position, the coolant in the engine loop and heater loop are separated and in the link position the coolant circulates through both loops. The valve movement is controlled by a PWM signal. A 50% duty cycle is a normal duty cycle. A 75% duty cycle represents a valve commanded to the link position. A 25% duty cycle represents a valve commanded to the ByPass position. The passenger compartment heater coolant control valve uses an internal position sensor that sends a signal to the hybrid powertrain control module to determine the valve position.
When the engine coolant temperature heats up, a valve learn procedure takes place. The hybrid powertrain control module 2 commands the valve to the link position and records the voltage coming back from the position sensor. Then the hybrid powertrain control module 2 commands the valve back to the bypass position and records the voltage coming back from the position sensor. The voltage values in both the link and bypass positions must fall within calibrated ranges.

OBDII Code P26A3 GMC - Engine Coolant Bypass Valve Range/Performance - AutoCodes.com — P26A3 GMC Code - Engine Coolant Bypass Valve Range/Performance

What does this mean?

What are the Possible Causes of the DTC P26A3 GMC?

Faulty Engine Coolant Bypass Valve
Engine Coolant Bypass Valve harness is open or shorted
Engine Coolant Bypass Valve circuit poor electrical connection

How to Fix the DTC P26A3 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 P26A3 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 P26A3 GMC Code

1. What does the OBDII code P26A3 mean on a GMC vehicle?

The P26A3 code indicates an issue with the Engine Coolant Bypass Valve, specifically a range or performance problem detected by the vehicle's computer.

2. What are the common symptoms of a P26A3 code in a GMC?

Symptoms may include the check engine light turning on, unusual engine temperature fluctuations, poor cabin heating, or reduced engine performance.

3. What causes the P26A3 code to appear?

The P26A3 code can be caused by a malfunctioning coolant bypass valve, wiring or connector issues, a stuck valve, or a failure in the engine control module (ECM).

4. Can I drive my GMC with the P26A3 code?

While it may be safe to drive short distances, ignoring the P26A3 code could lead to engine overheating or inefficient temperature control, potentially causing further damage.

5. How do I diagnose the P26A3 code on a GMC?

Diagnosis involves using an OBDII scanner to confirm the code, visually inspecting the coolant bypass valve and wiring, and testing the valve's operation to ensure proper functionality.

6. How is the P26A3 code fixed?

Common fixes include replacing the faulty coolant bypass valve, repairing damaged wiring or connectors, and clearing the code with a scanner after repairs.

7. How much does it cost to repair a P26A3 code on a GMC?

Repair costs vary but typically range from $150 to $400, depending on whether only the bypass valve needs replacement or additional wiring repairs are required.

8. Can a P26A3 code cause engine overheating?

Yes, if the coolant bypass valve fails to regulate coolant flow properly, it can lead to engine overheating or irregular temperature control.

9. What tools are needed to repair a P26A3 code on a GMC?

Youâ€™ll need an OBDII scanner, basic hand tools, and possibly a multimeter to test electrical connections.

10. How can I prevent the P26A3 code from reoccurring?

Regular maintenance of the cooling system, checking for leaks, and ensuring proper operation of the bypass valve can help prevent this code from reappearing.