I received a PO 758 code on my 1998 Isuzu Rodeo 3.2l V6 w/ (i believe) a 4L30 automatic transmission. The code description reads 'shift solenoid B - electrical problem'. This happened before, and my old shop told me that it was a failed PCM - they replaced it (under warranty) and it has worked fine until now. Now the dealer is telling me that I need a new transmission (at more than $4000) and another is saying that the tranny needs to be rebuilt. Both are telling me that the PCM has nothing to do with it; that it is in the tranny. I called my old shop and they said these shops don't know what they're talking about - that a PO758 error is strictly electrical in nature; if it was mechanical (specifically, the B solenoid inside the tran) then it would throw PO756 instead. Based on the fact that replacing the PCM fixed it before, i'm inclined to side with the old shop. The vehicle has no other codes displayed. the only physical symptoms displayed are at highway speeds; the tran shifts into overdrive but will not downshift at deceleration, then goes into the 3rd gear "failsafe". If the car is stopped and turned off four five minutes, the error clears and it drives normally until the next time it shifts into overdrive. very seldom, it occurs during normal city side-street driving (45mph and below). |
which shop is leading me in the right direction? what else could be causing the PCM to fail like this? I've had so many opinions that I don't know who to believe, including two different diagnoses by two different Isuzu dealers. I'm not going to just start blindly replacing transmissions and electrical components, hoping to get lucky.