Dave Blundell sez "Vernon (deluded) sent me much of this info."
As a rule of thumb, 90 PR4s have external PA sensors, and 91
ECUs have internal PA sensors. You can tell (to some degree) by looking at the "code" of the
ECU:
| Label | Description |
|---|
| A00 | 90 5 Speed (-33 program) |
| A01 | 90 5 Speed (?? program) |
| A02 | 90 5 Speed (-54 program) |
| A51 | 90 Automatic (?? program) |
| A52 | 90 Automatic (-54 program) |
| A10 | 91 5 Speed (-92 program) |
| A12 | 91 5 speed (-92 program) |
| A60 | 91 auto (-92 program) |
| A62 | 91 auto (-92 program) |
Ok, with that out of the way... It is easy to select whether to use a internal or external
PA sensor. See the following table:
| Part | External PA | Internal PA |
|---|
| PA Sensor | missing | installed |
| C103 | missing | present(103Z) |
| R92 | jumper | 10Kohm |
| C106 | missing | present(103Z) |
*edit*
It seems that the Internal PA
ECU is missing C106, and the External PA
ECU has C106 present.