arrow light flashing

realredf31 · Post by **realredf31** » 04 Jun 2011, 22:16

The arrow light started flashing on my 94 850.Before the arrow light came on it was acting strange by not wanting to shift first thing in the morning. I would put it in 3rd for a little while then shift it to drive and it would be fine. I checked to see if it pulled codes and it did not. It went off for a couple days then came back on and has been going off and on since. When its flashing it acts sluggish as well. I took it to a shop and they put it on a diagnostic machine and it pulled a code for a speed sensor. The guy said it was on the side of the trans. My question is would the speed sensor make the light come off and on intermittently, and what is the pnp sensor? I was reading info on same problem and everything I read said it was a PNP sensor. How do you know?

mdvolvo · Post by **mdvolvo** » 05 Jun 2011, 06:32

you probably have a p0500 code.( vehicle speed sensor ) I repaired this same problem for a friend of mine by replacing the speed sensor. It is located on the top of the tranmission under the air filter box.

Post by **Ozark Lee** » 05 Jun 2011, 06:33

Welcome to MVS,

The speed sensor is important but 99% of the automatic transmission problems are ultimately traced back to a failing PNP switch. A temporary cure - I'm on year 3 of the temporary cure for my son's 850 - is to row the shifter back and forth, quickly, a couple of dozen times.

What codes are you pulling from port A-1?

...Lee

mdvolvo · Post by **mdvolvo** » 05 Jun 2011, 07:17

P0500

BigRed · Post by **BigRed** » 05 Jun 2011, 13:39

mdvolvo wrote:you probably have a p0500 code.( vehicle speed sensor ) I repaired this same problem for a friend of mine by replacing the speed sensor. It is located on the top of the tranmission under the air filter box.

I'm having the same problem, P0500. I just disconnected the VSS and tested with a DVOM. The resistance starts in the 10's of millions of Ohms and then just climbs to just about 40 then resets to 0. I guess is the limit of the meter is 40 MOhms, and then it goes to infinity.

I couldn't find the specs for it, but I'm assuming with a reading of infinity that it is bad.

The wiring of it does not line up with what I read in AllData, so here's a pic if someone could please confirm I tested right sensor. This is the back half of the top of the transmission.

mdvolvo · Post by **mdvolvo** » 05 Jun 2011, 15:29

that is the right sensor

realredf31 · Post by **realredf31** » 06 Jun 2011, 07:15

Ozark Lee wrote:Welcome to MVS,

The speed sensor is important but 99% of the automatic transmission problems are ultimately traced back to a failing PNP switch. A temporary cure - I'm on year 3 of the temporary cure for my son's 850 - is to row the shifter back and forth, quickly, a couple of dozen times.

What codes are you pulling from port A-1?

...Lee

It doesn't pull any codes when we check it.

realredf31 · Post by **realredf31** » 06 Jun 2011, 08:06

The code that it pulled at the garage was a 114. It said speed sensor and he said it was on the side of the trans. I've been apprehensive about changing it because of the PNP sensor maybe being bad as both are expensive. I also have seen people say that if you clean all the connectors that this sometimes helps but i just don't know where all of them are.

mdvolvo · Post by **mdvolvo** » 06 Jun 2011, 18:24

the one that you showed in the picture is the one to replace
I changed that same sensor last week on a 1997 850T and it resolved the problem
The guy said that he had that light on for over a year and they could not resolve the problem.
If u have a good scanner such as a Launch you would see the code. P 0500