| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM connectors and ground circuits are okay. If either are defective, repair and repeat testing to confirm ECM malfunction. If ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. For programming procedures, see COMPUTER RELEARN PROCEDURES - IMPORT article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT. |
Note. For component location, see appropriate illustration in THEORY & OPERATION article.
Circuit Description
Park/Neutral Position (PNP) switch sends a signal to ECM when transaxle is in Neutral or Park. This signal is used for air/fuel correction and for idle speed control. DTC is set when 2 or more switches are on simultaneously for "P", R", "N", "2" and "L" position, or ECM is receiving an ON signal from PNP switch when vehicle has been operated for more than 30 seconds at 44 MPH or more and engine speed is 1500-2500 RPM. Possible causes are
- Shorted PNP switch circuit.
- Defective PNP switch.
- Defective ECM.
Diagnostic Aids
Using Toyota hand-held tester or scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.