My 1998 Volvo S90 (70K) had P0715 and P0705 codes 2 months ago. I was told that the gear position sensor (PNP switch) has to be replaced. I replaced it a week ago. However, after replacement the gear cannot be engaged. I can put the shift to D position for driving a just one minute, but then the gear became disengaged. I have to stop engine for several minutes and then I can drive for another one minute. Today I used ODB II code scanner and got 3 codes P0715, P0740, P0705. After erased the codes, the Check Engine light got off but the problem was still there (can only engage the gear for a minute). However, when I used the scanner to scan the codes, I could not get any codes. Can somebody help me to figure out what was wrong with my car? Why I could not get the error codes (the Check Engine light was off too)? Thanks.

 

Did you align it properly?

 

I'm not sure. I used the ohmmeter to connect to RED adn BULE lines in the
wiring and heard Beeps when the shift put at N position. What else I can do
to align it properly? BTW, how long the TCM can detect and store the code?
Why after I erased the code (P0715, P0705), I could not read the codes
any more? Thanks.

 

Did it also beep in park as well?

Once you clear them they are gone.

 

Tech, thanks for the prompt response. I have not tested it at P position. I will do it this afternoon
and will let you know the result (What you menat was that I should be beeps at both N and P
positions, right?). If after erasing the codes and the codes do not come back, does that mean
the P0715 and P0705 problems were resolved? If the gear cannot be engaged, are we supposed
to get some kind of error codes? Thanks.

 

Yes you should hear the beeps on both P and N.

Usually if the codes do not come bad yes they are resolved. But if it still doesn't go into gear it might be a problem inside the transmission.

 

Tech, thanks for the advice. I will check with my PNP switch alignment this afternoon and give it
another try and will keep you posted in this issue.

 

Tech, I checked with the new PNP switch again. Yes, it beeps at both N and P postions. Does
that mean the alignment is correct? Or do we have other method to test/adjust PNP switch
alignment? Since I also got P0715 code, which said that the RMP signal missing or Transmission
speed sensor signal missing, do you think I should replace transmission speed sensor too? Can
we replace the transmission speed sensor or RPM sensor by ourselves? Where are they located?
Thanks.

 

Yes the beeping in both positions means it is right.

The speed sensor should be the one in the side of the tranny on the drivers side. You can replace it.

 

Tech, thanks for the response. Do you have any reference that I can use to locate and learn how to replace the speed sensor? Is it easy to access to? Thanks.

 

I will check tomorrow but there should be a screw holding it in I believe. I also think it goes right into the side of the tranny.

 

Tech, thanks for check it for me. Have a good day and may hear from you tomorrow.