Mercedes A Class (W169) CVT 722.8 transmission ECU problems

This Mercedes A Class CVT (Continuously Variable Transmission) ECU is an extremely common problem for the 722.8 transmission. 

The root cause of this A Class gearbox problem is internal component breakdown of the ECU, commonly causing fault codes including: "0793 - The RPM Signal From Component Y3/9B4 CVT Secondary RPM Sensor Is Not Available" and "0722 - The RPM Sensor From Component Y3/9B5 CVT Output RPM Sensor Is Not Available", among others to be stored in the gearbox ECU. Faults with the output and secondary transmission speed sensor are also very common.

When the gearbox ECU fails, the vehicle will experience a loss of power, limp home mode and poor to limited gear selection. A warning message will also be displayed across the dash: Transmission Visit Workshop. 

This fault is not limited to only the Mercedes A Class gearbox ECU, these problems will also occur for the B Class CVT models.  

The usual solution for this CVT gearbox problem consist of replacing the gearbox ECU, valve chest, solenoids and subsequent coding. This can be avoided using our test and rebuild service, no need for subsequent programming as we retain the original coding. All we require is the gearbox ECU to resolve the 0722 and 0793 fault codes and eliminate the "Transmission Visit Workshop" display message.

Our rebuild option re-engineers the original manufacturing defects, meaning that the chance of further problems arising would be slim to none, but should any issues occur our lifetime warranty will ensure swift resolution of any problems. However, our work defect rate is lower than 0.6% on all of our rebuilds, so you can be assured of our very high standard of work.

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Common Failure symptoms:

• Limp home mode / safe mode
• Loss of power
• ‘Transmission visit workshop’ warning message on dashboard
• Transmission warning light on dashboard
• Not selecting gears
• Sticking in gear
• Output speed sensor fault
• Speed sensor fault

Common fault codes:  

• 0722 - The RPM Sensor From Component Y3/9B5 CVT Output RPM Sensor Is Not Available
• 0793 - The RPM Signal From Component Y3/9B4 CVT Secondary RPM Sensor Is Not Available
• 0717 - The RPM Signal From Component Y3/9B5 (CVT Output RPM Sensor) Is Not Available
• 0730 - The Gear Ratio In The Continuously Variable Automatic Transmission (CVT) Is Not Permissible
• 1634 - Component Y3/9N1 (CVT (Continuously Variable Automatic Transmission) Control Unit) Is Defective Or The Voltage Supply Is Faulty

Affected Vehicles:  

• Mercedes A-Class A150 / A160 / A170 / A180 / A200
• Mercedes B-Class B150 / B160 / B170 / B180 / B200

Test and rebuild: 

We test these problematic Mercedes CVT gearbox ECU’s under various, real-world load and driving conditions using our state of the art Hardware In-the-Loop (HIL) testing rig which will enable us to identify all internal faults. Our technicians will rebuild the transmission ECU and replace all common failing components with versions that are higher rated than standard, and then extensively re-test to ensure that no faults remain. This means that your rebuilt CVT gearbox ECU will perform as good as, if not better than a brand new replacement unit, ridding the Mercedes A Class of CVT gearbox problems once and for all.

Programming: 

This transmission control ECU is coded to the vehicle, however all original programming is retained meaning that once received back it is plug and play.

Quality: 

Our strict quality control: encompassing testing, components and workmanship will ensure only the highest level of work is carried out to meet our lifetime warranty standards. Due to our extremely high standards we work very closely with dealerships and specialists, offering a better solution to replacement.

Warranty:

Lifetime unlimited mileage*

How do I get my unit rebuilt?

Select your part number above and click: Get yours rebuilt

Print the payment/booking confirmation email.

Package the Mercedes A Class gearbox ECU inside a sturdy box with plenty of packaging material (make sure you include your confirmation email in the box).

Send us your package by tracked courier (the shipping instructions are on the confirmation email).

Once received we will test, rebuild and return your CVT transmission ECU with an unlimited mileage lifetime warranty. (if your unit turns out not to be faulty then we will refund your payment less a small testing fee and return shipping)

What if I don’t want to pay up front?

This is not a problem, if you prefer this option then follow the following steps:

Fill in and submit this test form.

Print the booking confirmation email.

Package the 722.8 gearbox ECU inside a sturdy box with plenty of packaging material (make sure you include your confirmation email in the box).

Send us your package by tracked courier (the shipping instructions are on the confirmation email).

Once received, we will test your transmission ECU and call you to advise on the outcome of testing, if your Mercedes A Class gearbox ECU is faulty and you choose to go ahead with the rebuild then we will take payment over the phone using a debit/credit card.

We will then rebuild your transmission ECU and return it to you with an unlimited mileage warranty.

If you require further information regarding this Mercedes A Class gearbox ECU then please contact us.