Fix High Idle on Subaru Outback and trouble code P0507
Shops are reporting a high incidence of P0507 High Idle codes on 2000-01 Subaru Outbacks (2.5L) when the idle isn’t really high at all. On earlier models the problem may be associated with a bad connection at the transmission neutral/safety switch. The switch may be mistakenly telling the PCM that the vehicle is in gear when it isn’t, or vice versa.
Disconnect the electrical connector from the transmission switch and check each pin to make sure it’s properly seated and not corroded. Next, clean all the ground connections in the engine compartment—clean, not just check. That means remove, sand a clean surface, and apply a coating of dielectric grease before re-assembly. Then clear the code and see if that fixes the problem. If it doesn’t, your vehicle may need a flash update for the PCM.
© 2012 Rick Muscoplat