Is the control unit 722.9 of the 7G-tronic gearbox defective?

A malfunction in the EGS 722.9 7G-tronic automatic transmission control unit is a common problem in Mercedes-Benz cars with automatic transmissions. This occurs because the metal parts and linings of the clutch plate, which float in the oil, wear out over time. The resulting filings clog the sensors and valves, requiring our controller to supply more power. This causes the sensors and circuits to overheat. Therefore, it is important to properly care for the controller's oil and change it regularly.

Symptoms of a damaged 7 G-Tronic control unit

The most common of these are:

• Engine warning light comes on
• The 7G-tronic gearbox switches to emergency mode, causing the car to lose power
• The gearbox jerks when shifting to D or R position
• No acceleration possible
• Unintelligible RPM signal from sensor - Signal disrupted
• No driving allowed
• Abrupt and incorrect gear changes
• The car will start in third gear when the MIL light is on
• No communication with the transmission controller
• Internal speed sensor error

The following errors can be caused by:

• Internal short circuits
• Wire break
• In-line short circuits
• Mechanical damage to the pulse ring
• Contamination of the filings

How to remove and install the automatic transmission controller on the Mercedes 7G-Tronic:

The main cause of automatic transmission failure in the Mercedes 7G-Tronic (722.9) is the oil (ATF). This oil lubricates the transmission and controls the hydraulics. While regular oil changes can help delay failure, keep in mind that, like any other mechanical component, it can break down over time. While it's best to leave repairs and updating the controller to professionals, we should also be able to remove contamination from the transmission ourselves.

Disassembly and assembly of the 7G-tronic controller in a few steps:

• We start by draining the oil from the gearbox
• We unscrew the lid of the box
• We remove the oil filter
• We dismantle the hydraulic plate (our 722.9 controller is screwed onto this)
• We dismantle the solenoid valves.
• We unscrew our controller from the board (we only send the 722.9 TCU controller)

We will send it to ABS Control Units for repair.

NB!
Remember to prepare the package securely for shipping. This prevents the control unit from being damaged during transport. This is important because it contains components such as sensors and valves that are easily damaged.
After the repair, the control unit must be reassembled, the gearbox must be bled, an adjustment must be made and the faults must be cleared.

Computer diagnostics and the most common errors it displays

The most common errors with 7G-tronic controllers are:

• P0715 , P0716 , P0717 , P0718 , P2204 , P2205 , P2206 , P2207 – Y3/8n1 Turbine Speed ​​Sensor (VGS)
• P2766 , P2767 , P2768 , 8705 , P2201 , 8704 , P2200 – Y3/8n2 Internal speed sensor
• P0720 , P0721 , P0722 , P0723 – Y3/8n3 Outboard/Output RPM Sensor
• P0705 , P0706 – Y3/8s1 Range Selection Sensor
• P0778 – Y3/8y5 Brake control solenoid valve B1
• P2725 – Y3/8y6 Brake Control Solenoid Valve B2
• P2725 , P0778 – Y3/8y7 Brake control solenoid valve B3
• P2759 – Y3/8y8 Solenoid valve for friction clutch control
• P0705 – Component Y3/8S1 (Selection Range Sensor (VGS)) is defective
• P0706 – Y3/8S1 (range sensor (VGS) selection)
• P2216 – Component Y3/8S1 (Selection Range Sensor (VGS)) The adjustment sequence occurred out of range