| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM connectors and ground circuits are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
Note. If DTCs P0110, P0115, P0120, P0440, P0441, P0446, P0450 and P0451 are output together, inspect ECM E2 circuit (sensor ground) between ECM and splice I8. Repair as necessary. See WIRING DIAGRAMS article.
Note. For component location, see appropriate illustration in THEORY & OPERATION article.
Circuit Description
Intake Air Temperature (IAT) sensor is a thermistor built into MAF meter and is used to monitor temperature of air flowing through MAF meter. DTC is set when ECM detects an open or short in IAT sensor circuit. ECM will operate in fail-safe mode if DTC P0110 is set. Possible causes are
- IAT sensor circuit is open or shorted.
- Defective IAT sensor (built into MAF meter).
- Defective ECM.
Diagnostic Aids
After confirming DTC P0110, use scan tool to access CURRENT DATA to confirm intake air temperature. If IAT sensor value displayed on scan tool is always -40°F (-40°C), IAT sensor circuit may be open. If IAT sensor value displayed on scan tool is always 284°F (140°C) or more, IAT sensor circuit may be shorted. Using scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.