What Does P0C28 Mean?
DTC P0C28 indicates the auxiliary transmission fluid pump motor is drawing more current than the maximum threshold. Excessive current typically results from a mechanically seized or binding pump, a short circuit within the motor windings, or an abnormally high fluid viscosity placing excessive load on the motor. This condition can damage the motor or its driver circuitry if not addressed.
Common Causes
30%
Auxiliary pump motor mechanically seized or partially jammed with debris
25%
Shorted motor windings drawing excessive current
20%
Transmission fluid heavily contaminated or incorrect viscosity
15%
Blocked or restricted fluid passages downstream of the pump
10%
Short-to-ground in the motor power wiring
Diagnostic Steps
1
Use a current clamp to measure actual pump motor current draw and confirm it exceeds the manufacturer's specification.
2
Inspect transmission fluid level and condition — low fluid, metal particles, or wrong viscosity can overload the pump.
3
Check the pump motor wiring for short-to-ground conditions using an ohmmeter with the motor disconnected.
4
Attempt to rotate the pump by hand (if accessible) to check for mechanical binding or foreign object obstruction.
5
If the pump is mechanically seized or motor resistance is abnormally low (shorted windings), replace the pump assembly.
Estimated Repair Cost
$300 - $1,300
Parts + labor, varies by vehicle and location
DTC P0C28 indicates the auxiliary transmission fluid pump motor is drawing more current than the maximum threshold. Excessive current typically results from a mechanically seized or binding pump, a short circuit within the motor windings, or an abnormally high fluid viscosity placing excessive load ...
The most common cause of P0C28 (Auxiliary Transmission Fluid Pump Motor Current High) is: Auxiliary pump motor mechanically seized or partially jammed with debris
Typical repair costs for P0C28 range from $300 to $1,300, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Excessive motor current can cause overheating of the pump motor and its driver circuit, potentially leading to a fire hazard in extreme cases or sudden loss of pump function. The transmission may overheat if the pump fails. Diagnose and repair promptly.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0C28 to identify the root cause.
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Quick Info
Category
Powertrain
System
Transmission / Hybrid Drivetrain
Difficulty
Type
Generic (SAE)
Recommended Tools
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