Faulty VSS causing flashing arrow?

Mabes101 · Post by **Mabes101** » 05 Jun 2019, 12:31

Hello all,

I've been chasing the flashing arrow on my 1997 850 GLT Automatic.
Problem first showed up after a long trip through Montana. I stopped to check the coolant level as it had a small leak on the coolant line sent back to the overflow tank. When I tried to start driving the car went into limp mode with flashing arrow and CEL.

So after looking into probable causes I tried changing the PNP switch. This worked for about a day and then the arrow came back. I then did 3 drains and refills of trans fluid and drove 300km (Mostly on the highway but made sure to run through all gears) before the arrow came back. Volvo then ran a diagnosis and came back with the Auto Trans 222 code, pointing towards the shift solenoid.

In the last week the Tracs off and ABS light have now shown up after car has been sitting in garage. As I pulled out of the garage and then put into park, the car moved a couple feet forward before slamming to a halt. I have recently been looking through the forums and seen similar problems with a faulty or failing VSS.

I pulled the VSS off the transmission yesterday and got a resistance reading of 435 ohms. I've seen a large range of sensor ohm readings depending on car year and transmission model and am trying to determine if the reading I got is within an acceptable range or if is causing problems by sending poor information to the TCM or ECU. Below is the sensor I have located near the back of the transmission.

download/file.php?id=9518

I'm looking at the VSS in the case I don't need to change the shift solenoid as the car actually shifts pretty good when arrow is not flashing.

Anyone know what the reading should be on that 1997 sensor or have any ideas where I should continue looking for the problem? Or should I be booking a Saturday to do the solenoid?

Sommerfeldt · Post by **Sommerfeldt** » 06 Jun 2019, 00:38

ESS/VSS should be 200-400 ohms. It doesn't seem to be within acceptable, but it could depend a little on temperature, etc. I'm not the best with electrical stuff, so I'm just referencing what the basic testing info says.

- S

tardcart · Post by **tardcart** » 06 Jun 2019, 04:51

Keep your code reader in the car and immediately erase to get out of limp mode. if you drive it it will ruin the clutches when the arrow is blinking. I assume the speedometer is working? Im under the impression that the speed sensor is not critical on the 850 as this is calculated by the ECU and ABS. On the 960 and 940 the speed sensor was critical to the transmission. Maby some one who knows this relationship can chime in. (ECU, ABS ,Speed sensor) so I doubt its the sensor. I would be inclined to revisit the PNP. no after market, and check alignment.