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Engine-Codes – GMC – P1E21 GMC

P1E21 GMC Code - Auxiliary Transmission Fluid Pump Control Module Hybrid/EV Battery Voltage Sense Circuit High Voltage

Quick Answer

The P1E21 diagnostic trouble code for GMC vehicles specifically pertains to the Auxiliary Transmission Fluid Pump Control Module Hybrid/EV Battery Voltage Sense Circuit High Voltage. Common causes include Malfunctioning auxiliary transmission fluid pump control module, Faulty wiring or connectors in the voltage sense circuit, Issues with the hybrid/EV battery, such as high voltage levels. 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
P1E21 GMC indicates Auxiliary Transmission Fluid Pump Control Module Hybrid/EV Battery Voltage Sense Circuit High Voltage.
Common causes
Common causes include Malfunctioning auxiliary transmission fluid pump control module, Faulty wiring or connectors in the voltage sense circuit, Issues with the hybrid/EV battery, such as high voltage levels.
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.
What is this?
Table of contents Created and updated by William Orellana on Sep 11, 2024
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Code P1E21 GMC Description

The P1E21 diagnostic trouble code for GMC vehicles specifically pertains to the Auxiliary Transmission Fluid Pump Control Module Hybrid/EV Battery Voltage Sense Circuit High Voltage. In hybrid or electric vehicles, the auxiliary transmission fluid pump plays a crucial role in maintaining proper transmission function and cooling. The control module is responsible for managing the voltage sense circuit, which monitors the voltage levels in the hybrid/EV battery to ensure optimal operation.

OBDII Code P1E21 GMC - Auxiliary Transmission Fluid Pump Control Module Hybrid/EV Battery Voltage Sense Circuit High Voltage
P1E21 GMC Code - Auxiliary Transmission Fluid Pump Control Module Hybrid/EV Battery Voltage Sense Circuit High Voltage

Common Causes of P1E21 GMC

  1. Malfunctioning auxiliary transmission fluid pump control module.
  2. Faulty wiring or connectors in the voltage sense circuit.
  3. Issues with the hybrid/EV battery, such as high voltage levels.
  4. Software glitches in the vehicle's computer system.
  5. General wear and tear on components related to the transmission system.

Symptoms of P1E21 GMC

  1. Illumination of the check engine light on the dashboard.
  2. Reduced fuel efficiency or overall performance of the vehicle.
  3. Transmission slipping or shifting irregularly.
  4. Overheating of the transmission fluid.
  5. Inability to switch between driving modes in hybrid vehicles.

How to Fix P1E21 GMC

  1. Use a diagnostic scanner to retrieve the specific trouble code and pinpoint the exact cause of the issue.
  2. Inspect the wiring and connectors in the voltage sense circuit for any damage or corrosion, repairing or replacing as needed.
  3. Test the hybrid/EV battery for high voltage levels and replace if necessary.
  4. Replace the auxiliary transmission fluid pump control module if it is found to be faulty.
  5. Clear the trouble code from the vehicle's computer system and test drive to ensure the issue has been resolved.

Cost to Fix P1E21 GMC

The typical repair costs for addressing the P1E21 GMC diagnostic trouble code can vary depending on the exact cause of the issue and the specific components that need to be repaired or replaced. In general, you can expect to pay anywhere from $200 to $800 for parts and labor. However, it's important to note that diagnosis time and labor rates at auto repair shops can vary significantly. It's recommended to check with local repair shops to get a more accurate estimate based on your vehicle make and model, as well as your location.

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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 P1E21 GMC Code

1. What are the common symptoms of OBDII code P1E21 in a GMC vehicle?

- Common symptoms include the check engine light coming on, reduced hybrid system performance, and potential issues with the transmission fluid pump.

2. What can cause the OBDII code P1E21 in a GMC vehicle?

- The code P1E21 can be triggered by a malfunction in the auxiliary transmission fluid pump control module or a high voltage sense circuit issue related to the hybrid/EV battery.

3. How serious is the OBDII code P1E21 in a GMC vehicle?

- This code can affect the performance and drivability of the vehicle, so it is recommended to address it promptly to prevent further damage to the hybrid/EV system.

4. How can I diagnose the OBDII code P1E21 in my GMC vehicle?

- Diagnosis typically involves using a scan tool to retrieve the code, checking the auxiliary transmission fluid pump control module, and inspecting the hybrid/EV battery voltage sense circuit for any issues.

5. Can I drive my GMC vehicle with the OBDII code P1E21?

- It is not recommended to drive the vehicle with this code present, as it may lead to further damage to the hybrid/EV system and affect the overall performance.

6. How can I repair the OBDII code P1E21 in my GMC vehicle?

- Repair may involve replacing the auxiliary transmission fluid pump control module, repairing any wiring or connection issues in the high voltage sense circuit, or addressing any other underlying causes of the code.

7. Will resetting the check engine light fix the OBDII code P1E21 in a GMC vehicle?

- Simply resetting the check engine light may temporarily clear the code, but it is important to diagnose and address the root cause of the issue to prevent it from recurring.

8. Can a DIYer fix the OBDII code P1E21 in a GMC vehicle?

- While some DIYers may have the skills to diagnose and repair this code, it is recommended to seek professional help, especially when dealing with high-voltage systems in hybrid vehicles.

9. How much does it typically cost to repair the OBDII code P1E21 in a GMC vehicle?

- The cost of repair can vary depending on the underlying issue, parts needed, and labor costs. It is advisable to get a professional diagnosis to determine an accurate estimate.

10. Are there any recalls or technical service bulletins related to the OBDII code P1E21 in GMC vehicles?

- It is advisable to check with a GMC dealership or visit the NHTSA website to see if there are any recalls or technical service bulletins related to this specific OBDII code in your vehicle.

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