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Common Mercedes A Class (W169) CVT Transmission ECU Issues
The Mercedes A Class W169 equipped with the CVT (Continuously Variable Transmission) 722.8 faces recurrent ECU (Electronic Control Unit) problems, leading to a range of symptoms and fault codes. This article addresses the root causes, symptoms, and solutions for resolving these issues, including a test and rebuild service that eliminates the need for subsequent programming.
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 Symptoms:
- Limp home mode / safe mode
- Loss of power
- ‘Transmission visit workshop’ warning message on the dashboard
- Transmission warning light illuminated
- Difficulty 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 Control Unit) Is Defective Or The Voltage Supply Is Faulty
Affected Vehicles:
Common Part Numbers:
Test and Rebuild Process:
The problematic Mercedes CVT gearbox ECU undergoes rigorous testing under various real-world conditions using a state-of-the-art Hardware In-the-Loop (HIL) testing rig. After identification of internal faults, technicians rebuild the transmission ECU, replacing common failing components with higher-rated versions. Extensive re-testing ensures optimal performance, equivalent to or better than a new replacement unit. Original programming is retained, offering a plug-and-play solution.
Quality Control:
Stringent quality control measures, including testing, component replacement, and workmanship, ensure adherence to lifetime warranty standards. The process aligns closely with dealership and specialist standards, providing a superior alternative to complete replacement.
Warranty:
Lifetime unlimited mileage warranty ensures long-term reliability and peace of mind for the vehicle owner.
How to Get Your Unit Rebuilt:
- Select your part number and proceed to the “Get yours Repaired” option.
- Print the payment/booking confirmation email.
- Package the Mercedes A Class gearbox ECU securely with the confirmation email.
- Send the package via tracked courier using the provided shipping instructions.
- Upon receipt, the ECU undergoes testing, rebuilding, and is returned with a lifetime warranty. In case of a non-faulty unit, a refund is issued, deducting a small testing fee and return shipping.
Option Without Upfront Payment:
- Fill and submit the Repair form.
- Print the booking confirmation email.
- Package the 722.8 gearbox ECU securely with the confirmation email.
- Send the package via tracked courier using the provided shipping instructions.
- After testing, a phone call provides the outcome. If faulty and proceeding with the rebuild, payment is taken over the phone, and the rebuilt ECU is returned with an unlimited mileage warranty.
Contact Information:
For further inquiries about the Mercedes A Class gearbox ECU, contact the provided information.
Contact AUTOTRONICS at 0116 276 7054 or email us at [email protected] for expert assistance. Our experienced engineers are here to solve all your queries and provide top-notch services.[/vc_column_text]
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