Automatically Shifted Manual Transmission/Transaxle: Testing and Inspection
Troubleshooting
=> [ Control Module Malfunction Behavior ]
=> [ Troubleshooting, Special Information ]
Before beginning any service work, the cause of damage should be pinpointed using "Guided Fault Finding".
The Guided Fault Finding is performed using the vehicle diagnosis, testing and information system (VAS 5051).
Thoughts before Fault Finding
You should try to create a logical fault finding process.
- Make yourself aware of what kind of complaint is occurring and what fault finding possibilities you have. Finding faults without a logical fault finding process would be magic and does not lead to success.
• It should also be clear: You should not find faults that others have already found and recognize. Try to see if your problem already had a solution described in technical problem solving.
• It is possible for you to contact your Technician Support Center (TSC) or the importer in your country. You should use this possibility! It can save you time, effort and money.
• It can also be helpful to be acquainted with the Diagnostic Trouble Code (DTC) entries from other control modules. Always interrogate all control modules. Also, have the BUS topic in mind during fault finding.
• You should a have diagnostic protocol available when contacting your importer or TSC.
Control Module Malfunction Behavior
The control module works with developed software. This software has the ability to execute electrical functions, monitor and control within milliseconds. Everything modern transmission electronics have going for them is located in this control module. This should also be considered during troubleshooting.
However, no electronics can do what they were not designed to do. Likewise, it is not possible to detect electronically, for example, where the transmission housing is leaking and oil is leaking. However, it is possible to detect the effects of low oil. A failure in gear monitoring would be recognized causing the control module to respond that both clutches are open (no traction).
You should know this during troubleshooting and also when working with the tester. It is possible that the cause for the malfunction might not be found during Guided Fault Finding.
In addition to updating the software, much has been done to protect the transmission should there be a malfunction (safety features). And so, when necessary, malfunctions are saved and a replacement program is started.
Control module behavior during a malfunction
If a component in the transmission malfunctions, the control module reacts with a replacement function. In order to protect the transmission, there are 4 different kinds of malfunctions:
1. The malfunction is so minor that it is possible to continue driving with a replacement program while maintaining driving safety. The driver is not notified of this via the selector lever transmission range display (Y5). The display shows the selector lever position normally. When can changes in driving behavior actually be detected.
2. Individual lever positions blink in the selector lever transmission range display. This informs the driver that this gear can presently not be selected. Example: Reverse, lever in "R" and vehicle drives backward. If "D" is engaged in this situation, the letter "D" blinks in the selector lever transmission range display. In this case, the control module prevents 1st gear from being engaged to avoid damaging the transmission. The gear is only engaged when vehicle is stopped. If you want to test this, do so carefully!
3. The selector lever transmission range display is completely lit up and blinks. The selector lever position is indicated. Example: the transmission fluid temperature is too high. Reasons could include: towing a trailer with too large of a load, auxiliary installations on front of vehicle, lack of cooling air.
4. The selector lever position cannot be recognized. The selector lever transmission range display blinks. Differences in the driving and shifting can definitely be felt. It is not possible to shift into reverse. There is a serious malfunction, a sub-transmission is switched off, transmission repair is necessary.
Troubleshooting, Special Information
Selector Lever Position Display, No "R"
Simultaneous lighting of all segments of Transmission Range (TR) selector lever display indicates transmission is in emergency running mode. The vehicle does not drive in reverse.
Tip Function Malfunction, No Gear Selection
Check lock washers on selector lever cable mounting bracket at top of transmission. Washer - B - especially must never be used twice.
The washer - B - can get lost if it loses its residual stress. The - arrow - points to cable adjustment bolt.
Drive Faulty, Insufficient Oil
First click here once, refer to => [ DSG Oil ] General Repair Information.
Only add oil if you have definitely seen that oil has leaked out. Under any other circumstances it is just a needless expense.
No faults are stored
This especially depends on you. Experience shows that often a fault that is attributed to the transmission was caused by other components or units.
It has occurred that poor shifting behavior was a result of insufficient engine air supply. Do not make mistakes like this.
If such faults are to be eliminated, you can work sensibly with the VW tester.
Faults are stored
First inform yourself of what the faults stored indicated. The VW tester offers the Guided Fault Finding possibility. You can find many causes of faults when the Guided Fault Finding is used correctly.
Malfunctions Outside Transmission
If, for example, there is a malfunction in the transmission: " ABS signal missing" is stored in the transmission and perhaps another control module also says: "ABS signal missing": Then do not continue to suspect the transmission control module is defective.
The entry simply means: the transmission (and possibly other control modules) is waiting for a signal via the BUS but is not receiving it. In this case, the Anti-lock Brake System (ABS) control module has a problem. Under no circumstances should you remove the Direct Shift Gearbox (DSG) Mechatronic (J743). In this example, the fault points to problems with the ABS.