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Engine-Codes – Generic – P1E21

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

Quick Answer

The diagnostic trouble code P1E21 refers to an issue with the Auxiliary Transmission Fluid Pump Control Module Hybrid/EV Battery Voltage Sense Circuit High Voltage. Common causes include Faulty Control Module: A malfunction in the auxiliary transmission fluid pump control module can trigger this code, Wiring or Connection Issues: Poor connections or damaged wiring related to the battery voltage sense circuit can cause high voltage readings, Battery Pack Problems: Issues with the hybrid or electric battery pack, such as overcharging or internal faults, can lead to 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 indicates Auxiliary Transmission Fluid Pump Control Module Hybrid/EV Battery Voltage Sense Circuit High Voltage.
Common causes
Common causes include Faulty Control Module: A malfunction in the auxiliary transmission fluid pump control module can trigger this code, Wiring or Connection Issues: Poor connections or damaged wiring related to the battery voltage sense circuit can cause high voltage readings, Battery Pack Problems: Issues with the hybrid or electric battery pack, such as overcharging or internal faults, can lead to 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 17, 2024
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Code P1E21 Description

The diagnostic trouble code P1E21 refers to an issue with the Auxiliary Transmission Fluid Pump Control Module Hybrid/EV Battery Voltage Sense Circuit High Voltage. In hybrid and electric vehicles, the auxiliary transmission fluid pump control module plays a crucial role in managing the transmission system's fluid circulation. The battery voltage sense circuit is responsible for monitoring the voltage levels in the vehicle's hybrid or electric battery pack.

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

Common Causes of P1E21

  1. Faulty Control Module: A malfunction in the auxiliary transmission fluid pump control module can trigger this code.
  2. Wiring or Connection Issues: Poor connections or damaged wiring related to the battery voltage sense circuit can cause high voltage readings.
  3. Battery Pack Problems: Issues with the hybrid or electric battery pack, such as overcharging or internal faults, can lead to high voltage levels.
  4. Software Glitch: An error or glitch in the vehicle's software or control module programming could also be a potential cause of this code.

Symptoms of P1E21

  1. Check Engine Light: The most common symptom associated with this code is the illumination of the check engine light on the vehicle's dashboard.
  2. Reduced Power: The vehicle may experience a decrease in power output or performance due to the high voltage sensed in the battery.
  3. Poor Fuel Efficiency: High voltage levels can impact the vehicle's fuel efficiency, leading to increased fuel consumption.
  4. Transmission Issues: The transmission may exhibit abnormal behavior, such as shifting problems or hesitation, as a result of the auxiliary transmission fluid pump control module issue.

How to Fix P1E21

  1. Diagnostic Scan: Begin by performing a comprehensive diagnostic scan to confirm the P1E21 code and identify the specific underlying cause.
  2. Inspect Wiring and Connections: Check the wiring and connections related to the battery voltage sense circuit for any damage or loose connections. Repair or replace as needed.
  3. Test Control Module: Test the auxiliary transmission fluid pump control module to determine if it is functioning correctly. Replace the module if it is found to be faulty.
  4. Battery Pack Inspection: Inspect the hybrid or electric battery pack for any issues that could be causing the high voltage readings. Address any battery pack problems accordingly.
  5. Clear Codes and Test Drive: After completing the repairs, clear the diagnostic trouble codes and test drive the vehicle to ensure that the issue has been resolved.

Cost to Fix P1E21

The typical repair costs for addressing the P1E21 code can vary depending on the specific cause of the issue and the extent of the repairs needed. In general, the cost of parts and labor for this repair could range from $200 to $800. It's important to note that the actual cost can vary based on factors such as the vehicle make and model, the location of the repair shop, and the rates charged for diagnosis and labor. It's recommended to consult with a qualified mechanic or auto repair shop for a more accurate estimate based on the individual circumstances.

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Code P1E21 Information for Specific Makes

  • P1E21 Buick — Auxiliary Transmission Fluid Pump Control Module Hybrid/EV Battery Voltage Sense Circuit High Voltage
  • P1E21 Cadillac — Auxiliary Transmission Fluid Pump Control Module Hybrid/EV Battery Voltage Sense Circuit High Voltage
  • P1E21 Chevrolet — Auxiliary Transmission Fluid Pump Control Module Hybrid/EV Battery Voltage Sense Circuit High Voltage
  • P1E21 GMC — Auxiliary Transmission Fluid Pump Control Module Hybrid/EV Battery Voltage Sense Circuit High Voltage
  • P1E21 Saturn — Auxiliary Transmission Fluid Pump Control Module Hybrid/EV Battery Voltage Sense Circuit High Voltage
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 Code

1. What are common symptoms of OBDII code P1E21?

The common symptoms of OBDII code P1E21 include the check engine light coming on, reduced fuel efficiency, and potential issues with the transmission fluid pump.

2. What could cause the OBDII code P1E21 to appear?

The OBDII code P1E21 typically appears due to a malfunction in the auxiliary transmission fluid pump control module hybrid/EV battery voltage sense circuit, resulting in high voltage readings.

3. How can I diagnose the issue related to OBDII code P1E21?

Diagnosing the issue related to OBDII code P1E21 may involve using a scan tool to read the code, checking the transmission fluid pump control module, and inspecting the hybrid/EV battery voltage sense circuit for any faults.

4. Can I continue driving with OBDII code P1E21 present?

It is not recommended to continue driving with OBDII code P1E21 present, as it can lead to further damage to the vehicle's transmission system and potentially affect other components.

5. What are the repair options for OBDII code P1E21?

Repair options for OBDII code P1E21 may include replacing the auxiliary transmission fluid pump control module, repairing or replacing the hybrid/EV battery voltage sense circuit, and clearing the code with a scan tool.

6. Are there any DIY tips for fixing OBDII code P1E21?

DIY tips for fixing OBDII code P1E21 include checking the electrical connections related to the transmission fluid pump control module and the battery voltage sense circuit for any loose or damaged wires.

7. How serious is OBDII code P1E21?

OBDII code P1E21 is considered a serious issue that should be addressed promptly to prevent further damage to the vehicle's transmission system and ensure safe driving conditions.

8. Can a mechanic reset OBDII code P1E21 without fixing the underlying issue?

While a mechanic can reset OBDII code P1E21 with a scan tool, it is important to address the underlying issue causing the code to prevent it from reoccurring and potentially causing more significant problems.

9. Is OBDII code P1E21 specific to hybrid or electric vehicles?

OBDII code P1E21 is specific to hybrid and electric vehicles due to its relation to the auxiliary transmission fluid pump control module and the hybrid/EV battery voltage sense circuit.

10. How much does it typically cost to repair OBDII code P1E21?

The cost to repair OBDII code P1E21 can vary depending on the extent of the issue, the specific components needing repair or replacement, and the labor rates of the repair shop. It is recommended to obtain quotes from different mechanics for an accurate estimate.

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