94 530i wont shift into drive

[chris_e34]

So i bought another 530i today. i got it at a steal, 900$ in excellent condition. The reason it was so cheap is because it has a major problem. When you shift the auto tranny into Drive, Reverse, or any other moving gear the engine stalls out. Im thinking it could be a bad tcu, but working on mid 90 chevys and fords, this could point to the torque converter. In all of your opinions what do you think i should try first? thanks

[632 Regal]

I would swap TCU's first with a known working one first, if that makes no differance then id say the TC and trans are bad. I might have a line on a 530 trans if you need one.


So i bought another 530i today. i got it at a steal, 900$ in excellent condition. The reason it was so cheap is because it has a major problem. When you shift the auto tranny into Drive, Reverse, or any other moving gear the engine stalls out. Im thinking it could be a bad tcu, but working on mid 90 chevys and fords, this could point to the torque converter. In all of your opinions what do you think i should try first? thanks

[chris_e34]

anyone got any good suggestions of where i can get a tcu? besides junkyards and anything local to me.

[chris_e34]

so i scanned the car for any codes today, and no luck. No codes whatsoever, interesting though, the scanner couldnt register the shift position. on the instrument cluster however, i can see the gear position as normal. i pulled the shifter cover off and resat all electrical connections, and probed with a test light each lead. i got light when i probed the d lead, p,r,2,3,4 did the same as normal. i am now completely in the dark. why would the instrument cluster register the gear, and program im running, but not the trans computer and scanner?

[chris_e34]

i have swapped tcm, dme, program selector switch, diagnosed shift selector switch, and made sure shift interlock is working properly. what else is there to diagnose in terms of the scanner not picking up what gear the tranny is in. i beleive if i solve this issue, the stall problem will be solved. anyone have any ideas????i am really stumped on this one. thanks

[pcross]

The last thing that comes to my mind is a bad speed sensor inside the tranny. Depending on the fault, the sensor could be sending a high-speed signal to the TCU when the car is at idle. If that happens, I believe a stall would be inevitable. The speed sensor is cheap enough. I am not sure there is a diagnostic test for it though. My Carsoft 6.5 program performs a through EGS test, but not a test for the speed sensor in the tranny. Maybe you can search BMW forums for "Transmission Speed Sensor problem".

[bad_manners_god]

The last thing that comes to my mind is a bad speed sensor inside the tranny. Depending on the fault, the sensor could be sending a high-speed signal to the TCU when the car is at idle. If that happens, I believe a stall would be inevitable. The speed sensor is cheap enough. I am not sure there is a diagnostic test for it though. My Carsoft 6.5 program performs a through EGS test, but not a test for the speed sensor in the tranny. Maybe you can search BMW forums for "Transmission Speed Sensor problem".

IS the Carsoft 6.5 program worth it? Are you able to clear annoying messages?

[pcross]

"IS the Carsoft 6.5 program worth it? Are you able to clear annoying messages?"

To me it is worth it weight in gold IF you understand the maxim, "garbage in, garbage out." Even the Carsoft people are quick to point out in their user's manual, "The handbook and explanatory text covering the single components are only support materials. They do not replace the competent knowledge of a mechanic or workshop guide." In other words, Carsoft will not fix your car. It will, however, provide a pointed reference to a detected problem area. It might, for example, point to erratic operation (not complete failure) of the fuel pump relay. If you know that the fuel pump relay is in the same electrical circuit as the EGS module, that in itself might point you to a probable source for erratic shift patterns. In a nutshell, Carsoft is the best diagnostic tool available to a non-BMW factory-trained tech. And, Yes. It does clear annoying messages (you have to take care of the diagnosed problem or the annoying message will re-occur later on of course) and with it you can reset oil, inspection and Check Engine lights. A Peake tool doesn't compare with the Carsoft program. After a complete system diagnosis - recommended for first time diagnostic run - you might not understand exactly what the problem is that Carsoft has pointed out about your ECU, but at least you know the problem you have is WITH the ECU and not the mass air flow sensor. Whew! I'm winded!