AW 55-50 No Reverse & VW 09G No Move

I recently received a phone call from a shop that was working on a 2001 Volvo with an AW55-50传播。从停车转移到反向时，车辆不会移动。如果选择器首次投入驱动器然后移动以反转，则接合正常。检查手动连杆，确认手动阀处于反向位置。我的第一个想法是“km没有反向综合征”，所以我问是否有可能在涡轮机速度传感器和输出速度传感器上交换连接器。技术人员说他会尝试连接器并回电。果然，在交换连接器后，车辆在选择时，车辆现在已经反转。

For those that do not know what "KM no reverse syndrome" is, here is the explanation. The KM transaxle had two speed sensors (pulse generators) which plugged into two holes in the case or, on other models, one hole in the case and one hole in the end cover. One sensor was for output speed and the other was for turbine speed. The two sensors were wired directly to a common connector. There was enough wire to plug the common connector into the main harness with the sensors installed in the wrong holes.

The KM Transmission Control Module (TCM) would inhibit reverse if it saw output speed. When the sensors were installed incorrectly, the output speed sensor would be reading the speed of the turbine shaft, which is normally spinning at about engine speed in park. The TCM sees output speed and does not allow a reverse engagement. When the selector is put in drive while stationary, all of the components in the transaxle come to a stop. If reverse is then selected, the TCM does not see any output speed and reverse will be allowed to engage. Most vehicles on the road today will have a reverse inhibit feature to protect thetransmissionand drivetrain. Not all will have the turbine speed sensor and output speed sensor close enough to swap the locations.

The09G, 09K and 09Mtransaxles in Audi and Volkswagen have a unique feature that will show up in your shop sooner or later. Most everyone knows that the brake pedal must be depressed in order to move the shifter from park. The new feature is that the brake pedal must remain depressed until the desired gear has been selected. If the brake pedal is released before the desired gear is selected the PRNDL lights will flash, the transmission will remain in neutral and the engine RPM's may fluctuate. Depressing the brake pedal will turn off the flashing PRNDL and allow the transmission to engage. This is a normal condition, there is no repair needed. Advise the driver to keep the brake pedal depressed until the transmission has engaged.

这些信息可以从VW Bulletin＃34 06 04日期为2006年8月17日，或奥迪公告＃34 09 02日期为2009年2月3日。

Jeff Parlee is Director of Product Support at Valve Body Xpress and a member of the SonnaxTASC Force®(Technical Automotive Specialties Committee), a group of recognized industry technical specialists, transmission rebuilders and Sonnax Industries Inc. technicians.