Q: Got a code of p0851 on 04 Forester xt. Shifter was stuck in park but I was able to jiggle it free. Today the oil light was flicking and stalling. Are these Related?

asked by on December 21, 2016

Shifter stuck in p. Jiggled free but got code "po851.Park-Neutral Switch input circuit low" Next day nearly stalls and at oil light flickers. Can the neutral safety switch be cause of both? Does " circuit low" mean NSs needs replacing? Do u have to remove exhaust to get at nss? Thanks

My car has 136000 miles.
My car has an automatic transmission.

Hi there. The neutral safety switch (transmission position switch (sensor)) on the transmission and the engine oil light on the dash have nothing in common. If the neutral safety switch has failed, then the transmission may start in gear or in any position that the shifter is in. Also, the engine may not start at all, but the engine will not stall out due to the switch failing. The engine oil light flickering only means that there is a loose connection to the oil pressure sending unit on the engine or the sending unit is failing or the oil pump is loosing oil pressure. I recommend putting a mechanical oil pressure gauge on the engine and testing the oil pressure when the light is flickering. If the light is flickering and the oil pressure is high, then the sending unit has a problem. If the oil pressure is very low and the light is flickering, then the oil pump is failing or the oil filter is plugged up. When removing the neutral safety switch, it is not necessary to drop the exhaust down, but if you need the extra room, then you could drop the exhaust down. If you need further assistance with replacing the transmission position switch (sensor) and diagnosing the low oil pressure, then seek out a professional, such as one from Your Mechanic, to help you.

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