OBD Guide
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P1E28

Auxiliary Transmission Fluid Pump Control Module Hybrid/EV Battery System Voltage

P1E28 is an OBD-II diagnostic trouble code meaning: Auxiliary Transmission Fluid Pump Control Module Hybrid/EV Battery System Voltage. Common causes: hybrid/electric battery voltage low, pump control module malfunction. Estimated repair cost: $56–222.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$56–222 (est.)

Symptoms

  • Uneven transmission operation
  • Check Engine Light Illuminates
  • Gear shifting problems
  • Reduced hybrid system efficiency
  • Unusual noises from the transmission

Causes

  • Hybrid/Electric Battery Voltage Low
  • Pump control module malfunction
  • Wiring harness damage
  • Grounding problems
  • Transmission fluid auxiliary pump malfunction

How to Fix

  1. Check hybrid/electric battery voltage
  2. Diagnose the pump control module
  3. Check the integrity of wiring and connections
  4. Test the operation of the auxiliary pump
  5. Replace faulty components

Related codes

P1E00P1E29P0A80

FAQ

What does the P1E28 code mean?

P1E28 is an OBD-II diagnostic trouble code that indicates: Auxiliary Transmission Fluid Pump Control Module Hybrid/EV Battery System Voltage

What causes a P1E28 error code?

The most common causes of P1E28 include: Hybrid/Electric Battery Voltage Low; Pump control module malfunction; Wiring harness damage; Grounding problems.

How do I fix a P1E28 diagnostic trouble code?

To fix P1E28: Check hybrid/electric battery voltage. Diagnose the pump control module. Check the integrity of wiring and connections. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P1E28?

Limited driving only, diagnose soon

How much does it cost to fix P1E28?

The estimated repair cost for P1E28 is $56–222. Actual cost depends on your vehicle, location, and labor rates.

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