I’m working on a 95 855, getting a check engine light with flashing arrow. When the fault occurs, the transmission downshifts hard and the speedo fluctuates wildly. Volvo scan tool reveals a 232 “speedo signal absent or faulty.” I’ve replaced the speedo sensor on the trans with a used part, as well as the instrument cluster with no effect. No sign of corrosion or loose pin connectors on the TCM or instrument cluster. I’ve had a similar problem caused by faulty abs module on newer 850/s70 models, but they’ve always had the ABS light on and the usual cluster of codes. Any advice would be greatly appreciated.

 

Sounds like the PNP switch. It tells the computer what gear is selelected. When it goes bad the computer gets conflicting info and flashes the upshift indicator. The PNP switch is on top of the transmission and below the airbox. About $150 and takes only 1 1/2 to replace.

 

if nothing else works, i'll try it, but there are no pnp codes, and it's not showing the usual starting in 3rd symptoms. also pnp was replaced 13 months ago according to our files.

 

Buphalo,

I bought my 850 for $300 because a shop told the owner that the Tranny was bad. I got intermittent flashing of the up arrow and CEL. I did not get 313 or PNP codes. I did the "ratchet clean" technique. Hold the shift button in and "row" the shifter from Park to 1 and back about 20 times real quick. This stopped the problem for about 2 or 3 days. So being new to Volvo's I researched farther and found that you do not always get the PNP switch code. I replaced the switch in about an 2 hours and Voila!! No more BAD tranny!

One other thing that strikes me is if the switch was replaced about 1 year ago could the pinch bolt have lossened and allowed it to be out of alignment??

 

If you have the Volvo scan tool check the ABS wheel speed on the sensors and make sure they are all reading the same speed.

 

A total of 3 posts FYR.

Just thought of adding a schematic on the TCM connection, in case if someone had removed it in the past and FOD got in there or is simply getting dirty, etc... When you remove any of the ECU's, disconnect the negative battery cable and let it sit for 20 minutes, until power supply to the ECU's disappears. After re-connecting the battery, the engine ECU has to re-learn idle and the radio code has to be reset.

I hope the problem gets resolved soon.


JPN

 

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