Strange transmission issue 2002 E530i Sport

[DomE39]

Strange issue has come up.

Whilst I was out enjoying the car yesterday I stopped for some groceries. When I returned to the car I jumped in and started it as per normal.

Upon moving into drive I noticed there was a thud, then driving off when the gearbox changed from 1st to 2nd it was harsh thud - everytime the tranmission changed gear it was harsh. Decided to quickly head home. No warning lights on dash.

Next morning checked level of fluid all okay / decided to reset ECU. Strangely car drives as its supposed to again - transmission shifts perfectly.

Any ideas? Could it be the TCU playing up or shift solenoids etc?

I've booked the car in to have the fluid and filter replaced next week.

Cheers.

[seagreen323i]

Hmm, probably wrong. But maybe the transmission found an error and reverted to maximum line pressure. When you reset it, the transmission reverted back.

Sent from my SM-G973U using Tapatalk

[ross1]

was it also shifting late? A wonky MAF sensor can do this as the engine DME and trans controller are in cahoots.

[jclausen]

Check for faults

[crazy4trains]

Before you do anything, ensure your battery and alternator are working correctly. Take voltage readings with the car running and after the car has sat for a few hours. Measure those voltages at the battery. Post those voltages here.

The transmission is very voltage sensitive. It will go into failsafe mode if it senses low voltage.

[balidawg]

Read the EGS fault codes using INPA, BMW Scanner 1.4, or the like. That will give specific clues.