My 98 Outback AWD has had the CEL on for the past month. The only symptom it has is irratic idleing and poor acceleration (may be a "get you home mode" from the ECU). However this only happens intermittently and when it does simply turning the engine off and restarting seem to clear the problem.
I took it to my local garage and they carried out a diagnostic with a Snap-on Computer and the codes found were: P0500 Vehicle Speed Sensor, P1507 Idle Control System Malfunction and P1540 Speed Sensor Malfunction 2. The speedo is working ok and they found good signals from both speed sensors going into the ECU. In there words - "sensors and signals to TCM (transmission computer?) and ECM (ECU) test fine, signal from ECM drops out intermittently"
Has any one heard of this type of fault? Could it be a faulty ECU or ECM if so how can this be determied prior to going to great expense on buying a new one. I am reluctant to go to a Subaru dealer from them to just start plugging in new parts to problem solve.
Any advice would be appreciated.