10-25-2012, 11:31 AM
Join Date: Jul 2012
My Ride: Smg M3 2002
So I did this mod: Car drives fine, but then after a while the gearbox light comes on and it shifts to "N" - Hydraulic fluid temperature sensor issue search forums for the resistor fix. (~$30)
Originally Posted by roadtrip1098
So far I have helped many people fix their SMG's through troubleshooting via PM's and locally through test driving and reading codes. This guide is for people that do not have access to the dealer software. I highly recommend that you get your codes read by someone with the appropriate software regardless of what this thread identifies as the issue. I make no guarantees that this thread will be correct 100% of the time, as with any troubleshooting, this offers a "best guess"
Go out to your car after it's cooled down.
Stand next to it.
Hit the unlock button.
Do you hear the SMG pump priming?
No - Best guess is the Salmon Relay (~$10)
How long does the pump run before it shuts off?
More than 10 seconds - Points to a low battery or bad accumulator (Battery ~$120) (Accumulator ~$Life savings)
Less than 10 seconds - Good news. The really expensive stuff seems to be ok.
Get in your car and put it in "N" with your foot on the brakes, start your car.
Car does not shift to "N" - Most likely the actuator, but could also be the brake pedal sensor.
Car shifts to "N" and starts.
Shift to "1" or "R"
"N" Flashes or car selects "2" instead of "1"- Bad Gear Position Sensor (~$300)
"1" or "R" Flashes - Hood or door sensor is most likely (DIY resistor fix ~$15)
The car shifts into the selected gear. Go for a drive.
Car shudders when taking off - perform SMG soft reset get above 40 MPH, shift to "N", pull back both paddles for about 10 seconds, shift back into gear. (~$0)
Car is not shifting to 1st at stops - Gear Position Sensor
Only usable gears are R,2,5 and 6 - Gear Position Sensor (~$300)
Car will sometimes miss shifts randomly for the same gears - Broken Compression Spring (~$20)
Car drives fine, but then after a while the gearbox light comes on and it shifts to "N" - Hydraulic fluid temperature sensor issue search forums for the resistor fix. (~$30)
When hitting shifter paddle, nothing happens but car shifts fine using stick - Bad Paddle Switch Recommend replacing both
Go home and relax, if none of this happened, you're probably going to be okay.
Open to suggestions for improving this thread. Will continue to edit this post as required.
- Added prices for most common fixes, DIY of course. The SMG is fairly inexpensive to own, especially considering the added clutch life from flawless shifting.
but car still drops me into Neutral - Why do ppl do that mod? And how much is the hydro temp sensor anyways? Maybe I should just buy that piece? If it is attached to the SMG pump then my pump is new and I dont see how it would already be failing... PLEASE HELP!