My Boxster has a problem of not having any speed signal with both the ABS and Spoiler warning light on.
The CEL light is NOT on. The transmission 4th Gear light is NOT on, either.
Now, the car has also been shifting poorly lately especially when cold. It lurches and slips and the gears don't engage or downshift properly. It is still driveable, but only if carefully shifting. The problem is more marked when driving gently. It seems to be masked when driving aggressively (the delay in shifting and slip between gears become less noticeable to me).
Having spent heaps of money on my Boxster last year alone, I have decided to trouble shoot this one myself. So I bought a OBD2 scanner.
It didn't return any speedo signal related codes!
It did return a P0740 which is "torque converter solenoid circuit open".
I am guessing that this means the torque converter is not engaging properly due to this solenoid not switching it right.
I have two questions for those in the know:
1. What is the most likely cause/fix to this P0740? Is replacing the solenoid a start and can that be DIY?
2. Can this P0740 also relate to the lack of speedo signal problem which surprisingly doesn't seem to show any related codes at the moment?
The scanner I used is from
http://www.obd-2.com/
Please help. The last thing I need now is a transmission replacement. It's a 1997 Boxster with 120kkm on it. No tiptronic service yet as far as I know.
P0740 error, poor shifting when cold, no speedo!
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