P172A — Hydraulic pressure — too high
Reference detail for fault code P172A on the DQ400E DSG transmission family.
What P172A indicates
The DQ400E transmission control unit stores P172A when it detects the following condition: Hydraulic pressure — too high. The fault concerns the hydraulic supply of the mechatronic unit. The control unit compares the required system pressure with the measured pressure and stores the code when the pressure is too low, too high, builds up too slowly, or the pump runs outside its normal operating time. A stored code does not by itself prove that a part has failed. Before replacing anything, check the live data, wiring, connectors, power supply and fluid condition, and confirm the fault on the vehicle.
Symptoms
- Delayed gear engagement or loss of drive
- Pump running unusually often or for a long time
- Emergency mode or no drive in gear
- Transmission warning light
Possible causes
- Internal hydraulic leakage (valve body, seals, accumulator)
- Faulty hydraulic pump or pump motor
- Low or contaminated transmission fluid
- Faulty pressure sensor or pressure control valve
Related components
Hydraulic pump / pump motor · Pressure accumulator · Mechatronic valve body
| Fault code | P172A |
|---|---|
| Transmission | DQ400E (6-speed hybrid DSG) |
| Factory code | 0DD |
| Category | Hydraulic pressure |
| Status | Documented — review advised |
This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part.
Have this code on your vehicle?
Send us the code and the vehicle details and we will confirm the correct unit or part by email.
Related pages for the DQ400E
DQ400E repair
Symptoms, mechatronic issues and what repair involves for this family.
DQ400E mechatronics
Replacement mechatronic unit and exchange options for this family.
DQ400E parts
Selected parts most often involved in repair for this family.
DQ400E fault codes
Every documented code for this family in one table.
Have a fault code to check?
Send us the code and the vehicle details and we will confirm the correct unit or part by email.