| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM connectors and ground circuit are okay. If either are suspect, 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 appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT. |
Note. If DTCs P0110, P0115 and P0120 are output together, check circuit E2 (Brown wire) between terminal No. 18 at ECM harness connector E11 and splice I6. Repair as necessary. See WIRING DIAGRAMS article.
Note. For component location, see appropriate illustration in THEORY & OPERATION article.
Circuit Description
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 air intake temperature. If temperature displayed on scan tool is -40°F (-40°C), IAT sensor circuit may be open. If temperature displayed on scan tool is 284°F (140°C) or more, IAT sensor circuit may be shorted. Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.