My 2003 S40 would occasionally go into limp mode, show the flashing arrow, and throw P0705 check engine light code. If I turn off the car and move/shove/row the gear **** back and forth ten times and restart the car, I would say 9 times out of 10 it got out of limp mode and drove normally. The flashing arrow might stay on that day, but the next day it would be off. CEL would stay on.

So I finally had a local independent mechanic replace the PNP switch. $100 labor, $130 part (OEM). He called me to say that after he replaced the switch, CEL would turn back on immediately. He tried adjusting the alignment of PNP switch a dozen times, to no avail. Tomorrow he's going to check if the new part maybe has a high rate of failure, in which case he may be able to get another unit from the parts dealer he uses. If that doesn't resolve the problem, he thinks it's got to be something *inside* the transmission -- which he doesn't want to go into.

Any advice? Am I screwed -- is it the transmission that's bad? Can it be something else?

 

I'd put the old one back on to see if it returned to the previous behavior.

 

My mechanic & I agreed that the best strategy for now is to leave the new PNP switch in there, and see if the car goes into limp mode. So far (2 days) ... so good.

Are there any other reasons why P0705 might be thrown?

I might take it into a Volvo dealer to see if they have a diagnosis....

 

OP here. I took my to an independent Volvo specialist 1.5 hours away, and they cleared the code in the TCM and in the ECM, and the CEL went off. They said you need a Volvo-specific tool to clear the code in the TCM--I guess my local mechanic did not have it.