Volkswagen Transmission Range Control switch questions
Hello fellow Techs I'm working in a VW Passat that is not displaying the correct gear on the instrument cluster or in scan data when looking at PIDS for the TCM. The transmission will slam into reverse and drive and sometimes will not shift up from first gear when driving. Check engine light is on with code 17090/p0706: Transmission Range Sensor 'A' Circuit Range/Performance - implausible signal. So far I have replaced the transmission range sensor and this made no change. I read about the TCM getting flooded under the passenger side carpet and sure enough this area was soaking wet. I inspected the TCM and connectors but surprisingly did not see any signs of corrosion or wire damage. I have verified that I have battery voltage at pin 26, 54, and 55 at the TCM and constant ground at pins 6, 28, and 34. I have discovered that when I shift through the gears with "koeo" the instrument cluster will display the correct gears. Once I turn the vehicle on and repeat this test, The parameter for "Terminal 15" in scan data drops to 0 volts even though I still have battery voltage on pin 54 and 55 directly at the TCM. At this point, all letters on gear display on instrument cluster are filled in and scan data does not display correct binary number for certain positions. I have also noticed that the brake switch input seems to have an affect on the binary number/position letter that the TCM displays. Inconsistently when hitting the brake pedal, the position displayed on scan data will change from 'D" to "Z3" and binary number will change by 1 digit. This seems to be part of the systems operation yet sometimes the gear position shows a "Z" value even when not touching the brake pedal. Any insight or additional knowledge of this system would be helpful. Thanks!
Hi Andrew this car is definitely going into limp mode due to the TCM or harness getting wet.there’s some hidden fuses you should check inside the ECM storage box in the left side cowl.if power and ground are good to the TCM then replace it.as for the water leak it’s coming from the right side cowl area from a failed cabin filter housing gasket.
Thanks Louie, I appreciate the response. We actually followed the harness back and found some splices to be wet. The splices were no damage or totally corroded like I would expect but there we darker colored. We installed new splices and found there to be no more issues. Thanks for the reply.
Can you confirm that you've monitored pin 54/55 with the engine running when Terminal 15 reads 0? What are you using to check this? Also, do you have reverse lights?
Jamie, Thanks for the response. I actually found some splices that were causing our issues.
Thanks Louie, I appreciate the response. We actually followed the harness back and found some splices to be wet. The splices were no damage or totally corroded like I would expect but there we darker colored. We installed new splices and found there to be no more issues. Thanks for the reply.