Mechatronic · DQ400E

DQ400E mechatronic replacement unit

The DQ400E is a 6-speed dual-clutch transmission with a wet clutch, designed for hybrid applications and also known as the 0DD. It combines the DSG principle with an interface to the vehicle’s hybrid system.

This page covers the symptoms most commonly associated with DQ400E faults, the mechatronic issues behind them, the fault codes that accompany them, and how to identify the correct mechatronic assembly or part.

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Technical overview

What the DQ400E mechatronic does

The DQ400E uses a wet dual clutch and is built for hybrid drivetrains, where the transmission works alongside an electric motor. The clutch and hydraulic design reflect that combined duty.

Faults on this family can involve hydraulic control and the hybrid control interface, because the transmission interacts with the hybrid system as well as the engine.

The mechatronic assembly holds the hydraulic and electronic control for the transmission. Because of the hybrid interface, confirming the exact unit and generation matters before ordering.

Transmission family	DQ400E (6-speed hybrid DSG)
Also known as	0DD
Clutch type	Wet dual clutch (hybrid)
Gears	6 forward
Factory code	0DD

What’s included

Contents of the DQ400E mechatronic assembly

The mechatronic assembly combines the hydraulic control unit and the electronic control unit in one housing. A replacement unit is supplied complete, ready to be fitted and adapted to the vehicle.

Hydraulic control unit

Valve body, solenoids and the pressure regulation that operates the clutches and shift forks.

Electronic control unit

The transmission control unit and its sensors, integrated with the hydraulic side in one assembly.

Actuators and sensors

The solenoids, speed sensors and position sensors that let the control unit operate and monitor the transmission.

Housing and connector

The machined housing and the electrical connector through which the unit communicates with the vehicle.

Replacement vs exchange

Two ways to source the DQ400E unit

Both options are agreed manually by email. There is no automated core deposit and no online payment.

Replacement unit. You receive a mechatronic assembly and keep your original unit. The simplest option when the original is not serviceable or not required back.
Exchange unit. You receive a unit and return your original. Exchange is agreed by email and is marked on the quotation request form.
Fitment and adaptation. The replacement unit is adapted to the vehicle after fitting, which requires a suitable diagnostic tool. This is confirmed in the quotation reply.

Technical references

DQ400E fault codes and repair information

The fault codes and repair pages for this family help confirm which unit is required before you order.

Code	Description	Category	Status
30097	Transmission fluid pressure sensor — manufacturer event-memory code	Pressure sensor	Review
Description The DQ400E transmission control unit stores 30097 when it detects the following condition: Transmission fluid pressure sensor — manufacturer event-memory code. The fault concerns a pressure sensor or pressure switch in the transmission. The control unit uses these signals for clutch and system pressure control, and stores the code when the signal is out of range, too low or implausible. 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 Harsh engagement or judder Emergency mode Pump running unusually Transmission warning light Possible causes Faulty pressure sensor Wiring or connector fault A real hydraulic pressure problem Fault in the control electronics Transmission: DQ400E Category: Pressure sensor Status: Documented — review advised Related components: Pressure sensor · Mechatronic unit This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DQ400E quote DQ400E repair
P0218	Transmission overtemperature condition	Hydraulic pressure	Review
Description The DQ400E transmission control unit stores P0218 when it detects the following condition: Transmission overtemperature condition. 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 Transmission: DQ400E Category: Hydraulic pressure Status: Documented — review advised Related components: Hydraulic pump / pump motor · Pressure accumulator · Mechatronic valve body This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DQ400E quote DQ400E repair
P0607	Control module — implausible operation / hardware related	Internal control unit (TCU)	Review
Description The DQ400E transmission control unit stores P0607 when it detects the following condition: Control module — implausible operation / hardware related. The fault originates in the transmission control electronics integrated into the mechatronic unit. The unit's self-diagnosis has detected an internal error, an implausible internal value or a software problem. 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 Emergency mode or no drive Intermittent faults that change with temperature No communication with the diagnostic tester Transmission warning light Possible causes Faulty control electronics (circuit board, integrated sensors, bond wires) Overheating or moisture damage Software fault or interrupted programming Unstable power supply Transmission: DQ400E Category: Internal control unit (TCU) Status: Documented — review advised Related components: Transmission control unit (TCU) · Mechatronic unit This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DQ400E quote DQ400E repair
P0715	Input / turbine speed sensor A — circuit	Speed sensor	Review
Description The DQ400E transmission control unit stores P0715 when it detects the following condition: Input / turbine speed sensor A — circuit. The fault concerns a speed signal. The control unit needs the input (clutch/turbine) and output shaft speeds to control shifts and clutch slip, and stores the code when a signal is missing, implausible or electrically faulty. 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 Harsh or badly timed shifts Emergency mode Incorrect gear or speed display Transmission warning light Possible causes Faulty speed sensor in the mechatronic unit Wiring or connector fault Metal debris on the sensor or sender wheel Fault in the control electronics Transmission: DQ400E Category: Speed sensor Status: Documented — review advised Related components: Input speed sensor · Output speed sensor · Mechatronic unit This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DQ400E quote DQ400E repair
P0731	Gear 1 — incorrect ratio	Gear ratio / gear loss	Review
Description The DQ400E transmission control unit stores P0731 when it detects the following condition: Gear 1 — incorrect ratio. This is a mechanical plausibility check: the control unit compares the input and output shaft speeds with the ratio expected for the selected gear. The code is stored when the calculated ratio does not match or a gear drops out unexpectedly. 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 Engine revs flare without acceleration Gear drops out or the transmission stays in one gear Emergency mode Transmission warning light Possible causes Clutch slip Gear disengaging because of a gear selector or shift fork fault Faulty input or output speed sensor Internal mechanical damage (gears, synchronisers, bearings) Transmission: DQ400E Category: Gear ratio / gear loss Status: Documented — review advised Related components: Speed sensors · Gear selector / shift fork · Dual clutch · Gear set This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DQ400E quote DQ400E repair
P074A	Gear 1 — incorrect ratio	Gear ratio / gear loss	Review
Description The DQ400E transmission control unit stores P074A when it detects the following condition: Gear 1 — incorrect ratio. This is a mechanical plausibility check: the control unit compares the input and output shaft speeds with the ratio expected for the selected gear. The code is stored when the calculated ratio does not match or a gear drops out unexpectedly. 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 Engine revs flare without acceleration Gear drops out or the transmission stays in one gear Emergency mode Transmission warning light Possible causes Clutch slip Gear disengaging because of a gear selector or shift fork fault Faulty input or output speed sensor Internal mechanical damage (gears, synchronisers, bearings) Transmission: DQ400E Category: Gear ratio / gear loss Status: Documented — review advised Related components: Speed sensors · Gear selector / shift fork · Dual clutch · Gear set This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DQ400E quote DQ400E repair
P0842	Transmission fluid pressure sensor — low signal	Pressure sensor	Review
Description The DQ400E transmission control unit stores P0842 when it detects the following condition: Transmission fluid pressure sensor — low signal. The fault concerns a pressure sensor or pressure switch in the transmission. The control unit uses these signals for clutch and system pressure control, and stores the code when the signal is out of range, too low or implausible. 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 Harsh engagement or judder Emergency mode Pump running unusually Transmission warning light Possible causes Faulty pressure sensor Wiring or connector fault A real hydraulic pressure problem Fault in the control electronics Transmission: DQ400E Category: Pressure sensor Status: Documented — review advised Related components: Pressure sensor · Mechatronic unit This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DQ400E quote DQ400E repair
P0867	Transmission fluid pressure — low / implausible	Hydraulic pressure	Review
Description The DQ400E transmission control unit stores P0867 when it detects the following condition: Transmission fluid pressure — low / implausible. 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 Transmission: DQ400E Category: Hydraulic pressure Status: Documented — review advised Related components: Hydraulic pump / pump motor · Pressure accumulator · Mechatronic valve body This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DQ400E quote DQ400E repair
P0962	Pressure control valve 1 — low control current	Valve / solenoid electrical	Review
Description The DQ400E transmission control unit stores P0962 when it detects the following condition: Pressure control valve 1 — low control current. The fault is electrical: the control unit monitors the current and resistance of each solenoid and pressure control valve, and stores the code when it detects an open circuit, a short circuit or a control current outside the expected range. 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 Harsh or missing gear changes Some gears unavailable Emergency mode, often with only certain gears Transmission warning light Possible causes Faulty solenoid or pressure control valve coil Damaged internal wiring or connector in the mechatronic unit Fault in the valve driver stage of the control electronics Contaminated transmission fluid affecting valve operation Transmission: DQ400E Category: Valve / solenoid electrical Status: Documented — review advised Related components: Solenoid / pressure control valve · Mechatronic valve body · Transmission control unit (TCU) This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DQ400E quote DQ400E repair
P0966	Pressure control valve 2 — low control current	Valve / solenoid electrical	Review
Description The DQ400E transmission control unit stores P0966 when it detects the following condition: Pressure control valve 2 — low control current. The fault is electrical: the control unit monitors the current and resistance of each solenoid and pressure control valve, and stores the code when it detects an open circuit, a short circuit or a control current outside the expected range. 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 Harsh or missing gear changes Some gears unavailable Emergency mode, often with only certain gears Transmission warning light Possible causes Faulty solenoid or pressure control valve coil Damaged internal wiring or connector in the mechatronic unit Fault in the valve driver stage of the control electronics Contaminated transmission fluid affecting valve operation Transmission: DQ400E Category: Valve / solenoid electrical Status: Documented — review advised Related components: Solenoid / pressure control valve · Mechatronic valve body · Transmission control unit (TCU) This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DQ400E quote DQ400E repair
P172A	Hydraulic pressure — too high	Hydraulic pressure	Review
Description 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 Transmission: DQ400E Category: Hydraulic pressure Status: Documented — review advised Related components: Hydraulic pump / pump motor · Pressure accumulator · Mechatronic valve body This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DQ400E quote DQ400E repair
P172B	Hydraulic pressure — too low	Hydraulic pressure	Review
Description The DQ400E transmission control unit stores P172B when it detects the following condition: Hydraulic pressure — too low. 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 Transmission: DQ400E Category: Hydraulic pressure Status: Documented — review advised Related components: Hydraulic pump / pump motor · Pressure accumulator · Mechatronic valve body This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DQ400E quote DQ400E repair
P1735	Clutch 1 position sensor — electrical fault	Clutch faults	Review
Description The DQ400E transmission control unit stores P1735 when it detects the following condition: Clutch 1 position sensor — electrical fault. The fault concerns clutch control: engagement, adaptation, torque limitation or clutch temperature. The control unit compares the commanded clutch position or pressure with the measured value and stores the code when the difference or the adapted value leaves the permitted range. 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 Judder when pulling away Delayed or harsh engagement Reduced power or emergency (limp-home) mode Transmission warning on the instrument cluster Possible causes Clutch wear or overheating Adaptation values out of range or basic setting not performed Deviation in hydraulic clutch actuation Faulty clutch position or pressure sensor in the mechatronic unit Transmission: DQ400E Category: Clutch faults Status: Documented — review advised Related components: Dual clutch · Clutch actuator / pressure control valve · Mechatronic unit This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DQ400E quote DQ400E repair
P1736	Clutch 2 position sensor — electrical fault	Clutch faults	Review
Description The DQ400E transmission control unit stores P1736 when it detects the following condition: Clutch 2 position sensor — electrical fault. The fault concerns clutch control: engagement, adaptation, torque limitation or clutch temperature. The control unit compares the commanded clutch position or pressure with the measured value and stores the code when the difference or the adapted value leaves the permitted range. 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 Judder when pulling away Delayed or harsh engagement Reduced power or emergency (limp-home) mode Transmission warning on the instrument cluster Possible causes Clutch wear or overheating Adaptation values out of range or basic setting not performed Deviation in hydraulic clutch actuation Faulty clutch position or pressure sensor in the mechatronic unit Transmission: DQ400E Category: Clutch faults Status: Documented — review advised Related components: Dual clutch · Clutch actuator / pressure control valve · Mechatronic unit This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DQ400E quote DQ400E repair
P179C	Main pressure valve — electrical malfunction	Valve / solenoid electrical	Review
Description The DQ400E transmission control unit stores P179C when it detects the following condition: Main pressure valve — electrical malfunction. The fault is electrical: the control unit monitors the current and resistance of each solenoid and pressure control valve, and stores the code when it detects an open circuit, a short circuit or a control current outside the expected range. 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 Harsh or missing gear changes Some gears unavailable Emergency mode, often with only certain gears Transmission warning light Possible causes Faulty solenoid or pressure control valve coil Damaged internal wiring or connector in the mechatronic unit Fault in the valve driver stage of the control electronics Contaminated transmission fluid affecting valve operation Transmission: DQ400E Category: Valve / solenoid electrical Status: Documented — review advised Related components: Solenoid / pressure control valve · Mechatronic valve body · Transmission control unit (TCU) This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DQ400E quote DQ400E repair
P17BF	Hydraulic pump system overload protection	Hydraulic pressure	Review
Description The DQ400E transmission control unit stores P17BF when it detects the following condition: Hydraulic pump system overload protection. 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 Transmission: DQ400E Category: Hydraulic pressure Status: Documented — review advised Related components: Hydraulic pump / pump motor · Pressure accumulator · Mechatronic valve body This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DQ400E quote DQ400E repair
P189C	Function restriction — insufficient pressure build-up	Hydraulic pressure	Review
Description The DQ400E transmission control unit stores P189C when it detects the following condition: Function restriction — insufficient pressure build-up. 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 Transmission: DQ400E Category: Hydraulic pressure Status: Documented — review advised Related components: Hydraulic pump / pump motor · Pressure accumulator · Mechatronic valve body This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DQ400E quote DQ400E repair
P2711	Unexpected mechanical gear disengagement	Gear ratio / gear loss	Review
Description The DQ400E transmission control unit stores P2711 when it detects the following condition: Unexpected mechanical gear disengagement. This is a mechanical plausibility check: the control unit compares the input and output shaft speeds with the ratio expected for the selected gear. The code is stored when the calculated ratio does not match or a gear drops out unexpectedly. 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 Engine revs flare without acceleration Gear drops out or the transmission stays in one gear Emergency mode Transmission warning light Possible causes Clutch slip Gear disengaging because of a gear selector or shift fork fault Faulty input or output speed sensor Internal mechanical damage (gears, synchronisers, bearings) Transmission: DQ400E Category: Gear ratio / gear loss Status: Documented — review advised Related components: Speed sensors · Gear selector / shift fork · Dual clutch · Gear set This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DQ400E quote DQ400E repair
P2884	Engine disconnect clutch K0 — stuck open	Clutch faults	Review
Description The DQ400E transmission control unit stores P2884 when it detects the following condition: Engine disconnect clutch K0 — stuck open. The fault concerns clutch control: engagement, adaptation, torque limitation or clutch temperature. The control unit compares the commanded clutch position or pressure with the measured value and stores the code when the difference or the adapted value leaves the permitted range. 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 Judder when pulling away Delayed or harsh engagement Reduced power or emergency (limp-home) mode Transmission warning on the instrument cluster Possible causes Clutch wear or overheating Adaptation values out of range or basic setting not performed Deviation in hydraulic clutch actuation Faulty clutch position or pressure sensor in the mechatronic unit Transmission: DQ400E Category: Clutch faults Status: Documented — review advised Related components: Dual clutch · Clutch actuator / pressure control valve · Mechatronic unit This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DQ400E quote DQ400E repair
U0101	Lost communication with TCM	Communication	Review
Description The DQ400E transmission control unit stores U0101 when it detects the following condition: Lost communication with TCM. The fault concerns data communication between the transmission control unit and other control units on the powertrain CAN bus. The code is stored when messages are missing or corrupted, or the bus hardware reports an error. 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 Gear display missing or flashing Emergency mode Several control units reporting communication faults Transmission not reachable with the diagnostic tester Possible causes Wiring or connector fault on the CAN bus Power supply or ground fault at the control unit Faulty transmission control unit Fault in another control unit on the same bus Transmission: DQ400E Category: Communication Status: Documented — review advised Related components: Powertrain CAN bus · Transmission control unit (TCU) · Connectors and wiring This code is documented but not independently confirmed. Confirm it against the specific vehicle before ordering any part. Open full detail Request a DQ400E quote DQ400E repair

All DQ400E fault codes →

Price & exchange

DQ400E mechatronic unit

Prices are confirmed per request, because the correct unit depends on the transmission generation and the vehicle.

DQ400E Exchange available

DQ400E DSG mechatronic unit — 0DD927770

Refurbished DSG mechatronic unit for the DQ400E (6-speed hybrid DSG), OEM part number 0DD927770 (0DD 927 770). Supplied as a complete assembly with the integrated control electronics.

Replacement unit Price on request