On-Board Diagnostic (OBD), Function
On Board Diagnostic (OBD), function
The Multitronic o1i constantly variable automatic transmission is controlled electronically/hydraulically.
The Transmission Control Module (TCM) receives information from components which influence the shifts. Based on this information, the control module activates the applicable proportioning valves in the valve body. The three proportioning valves regulate the fluid pressure generated by the ATF pump.
Proportioning valve 1 regulates the opening and closing of the clutches or brakes respectively.
Proportioning valve 2 controls the transmission ratio between the two disc sets, depending on driving conditions, i.e. it regulates the pressures on the adjusting cylinders of the two disc sets and keeps the chain at a constant tension.
Proportioning valve 3 regulates ATF cooling of the transmission.
A more precise description and operation of the individual valves can be found in:
Refer to Self-study Program Course No. 951103, Variable Automatic Transmission, Multitronic 01J
Transmission Control Module (TCM) DTC Recognition
The term "On Board Diagnostic" refers to the electrical/electronic part of the controls.
The control module is equipped with a Diagnostic Trouble Code (DTC) memory so that in the event of the failure of an electrical/electronic component, or in the event of an open circuit the cause of the malfunction can be determined quickly.
The potential of the On Board Diagnostic (OBD) system can only be fully exploited with the V.A.G. 5051 Vehicle Diagnostic Measurement and Information System or with the V.A.G. 1551 scan tool, operating mode 1 "Rapid Data Transmission."
For functions which the V.A.G. 5051 Vehicle Diagnostic Measurement and Information System or the V.A.G. 1551 scan tool can cover, Overview of Selectable Functions.
Malfunctions are recognized by means of electrical signals. If malfunctions occur in the sensors or components being monitored, they are stored in the DTC memory indicating the type and location of the malfunctions.
If a malfunction is present it is saved as a statistical error. If the malfunction occurs only briefly and is then no longer present it becomes an intermittent malfunction after the ignition is switched off and on again.
Malfunctions occurring sporadically (intermittently, occasionally) are displayed on the screen as "sporadic."
After 40 engine cold starts (followed by transmission warm-up) the sporadic malfunctions are automatically deleted from the DTC memory
A maximum of 10 trouble codes are stored in the DTC memory. If an eleventh trouble code should be detected with 10 statistical trouble codes, emergency shutoff takes place.
If 10 trouble codes have already been saved in the DTC memory but they are not all statistical, and an eleventh trouble code is added, the oldest existing sporadic trouble code is overwritten.
Transmission Control Module (TCM) safety functions
In the event of a failure of individual or several components or sensors, the control module -J217- activates corresponding substitute functions. This ensures non-destructive operation of the transmission with the consequent effect on the function and quality of the shifts.
Three conditions can be distinguished which are recognized by multitronic.
1. The trouble code is stored and a substitute program allows the vehicle to continue to be driven (with some limitations). The driver is not alerted to this condition, since it is not critical to safety nor for the transmission. The transmission range display in the instrument cluster indicates as normal the particular range that has been selected -arrow-. The driver may notice a difference in vehicle driveability and contact an authorized dealer.
2. The trouble code is stored and a substitute program allows the vehicle to continue to be driven (with some restrictions). The fully illuminated transmission range display in the instrument cluster shows the driver a simple malfunction -arrow-. This malfunction is barely noticeable to the driver, but the brightly lighted transmission range display is intended to indicate that he or she should consult an authorized dealer as soon as possible to avoid subsequent damage in the transmission.
3. A flashing transmission range indicator in the instrument cluster points to a serious malfunction in the transmission -arrow-. The condition is critical to safety or for the transmission.
CAUTION: A flashing transmission range display Indicator In the Instrument cluster means the vehicle could come to an Immediate stop or might not continue operation the next time the vehicle is stopped. This could mean that stopping at a traffic signal can cause traffic to be obstructed.
The flashing transmission range display is requesting the driver to stop his or her vehicle at the nearest possible location and to inform an Audi authorized dealer.
Note: In specific cases following a short wai4 driving can be resumed by restarting the engine. In any case, the driver should immediately consult an Audi authorized dealer.
If the multitronic control module -J217- fails, for example, due to a loss of the voltage feed, it will not be possible to continue driving.
CAUTION: When the vehicle Is towed, the transmission selector lever must be In position N, and It must not be towed more than 50 km and not above 50 km/h, otherwise the transmission will be destroyed.