Fault Family System: Powertrain (P-Codes) 16 SAE Codes

Trans Fluid Pump Supply Hydraulic

Diagnostic & Technical Explanation

Code P0B09 sets when the control module monitors the electric transmission fluid pump's hydraulic supply-pressure feedback and the reported value does not build or hold within the window expected after the pump is commanded on. The most common physical causes are a clogged fluid pickup screen restricting the pump's suction side, a corroded or unseated connector at the pressure-feedback sensor, and worn pump-gear or gerotor clearance that lets pressure bleed off internally. This is a hydraulic-output fault distinct from the pump motor's electrical phase-current fault or its control-module communication fault covered by the other two families in this pump's group.

These 16 diagnostic trouble codes share one detection mechanism and one repair path, which is why MechanicDB groups them into a single authored fault family rather than repeating the same explanation 16 times.

Codes in this family (16)

Code	Definition	Repair coverage
P0B09	Electric/Auxiliary Transmission Fluid Pump A Motor Supply Voltage Circuit/Open	3 ranked fixes
P0B0A	Electric/Auxiliary Transmission Fluid Pump A Motor Supply Voltage Circuit Low	3 ranked fixes
P0B0B	Electric/Auxiliary Transmission Fluid Pump A Motor Supply Voltage Circuit High	3 ranked fixes
P0B0C	Electric/Auxiliary Transmission Fluid Pump A Hydraulic Leakage	3 ranked fixes
P0DE4	Electric/Auxiliary Transmission Fluid Pump A Motor Over Temperature	3 ranked fixes
P276A	Electric/Auxiliary Transmission Fluid Pump B Motor Supply Voltage Circuit/Open	3 ranked fixes
P276B	Electric/Auxiliary Transmission Fluid Pump B Motor Supply Voltage Circuit Low	3 ranked fixes
P276C	Electric/Auxiliary Transmission Fluid Pump B Motor Supply Voltage Circuit High	3 ranked fixes
P277A	Electric/Auxiliary Transmission Fluid Pump B Hydraulic Leakage	3 ranked fixes
P277D	Electric/Auxiliary Transmission Fluid Pump B Motor Over Temperature	3 ranked fixes
P27E1	Electric/Auxiliary Transmission Fluid Pump A Pressure Too Low	3 ranked fixes
P27E2	Electric/Auxiliary Transmission Fluid Pump B Pressure Too Low	3 ranked fixes
P27E3	Electric/Auxiliary Transmission Fluid Pump Control Valve Circuit/Open	3 ranked fixes
P27E4	Electric/Auxiliary Transmission Fluid Pump Control Valve Circuit Range/Performance	3 ranked fixes
P27E5	Electric/Auxiliary Transmission Fluid Pump Control Valve Circuit Low	3 ranked fixes
P27E6	Electric/Auxiliary Transmission Fluid Pump Control Valve Circuit High	3 ranked fixes

What this page does not show

This page publishes the fault mechanism and the code index. The licensed dataset adds, for every one of the 15,886 codes, the full authored repair set (56,729 procedures in total) with the fields deliberately withheld here:

Procedures 2..n after the first-listed procedure
Aftermarket parts cost ranges in USD (est_parts_cost_min/max_usd)
Professional labor-hour estimates (est_labor_hours)
Step-by-step diagnostic and repair instructions
Replacement-part mappings and catalog lookups
6,637 manufacturer-specific OEM codes across 32 makes ($149 tier)

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