DTC 23 - Intake Air Temperature Sensor Voltage High Test FC-3A

1. Using DRB-II, read Intake Air Temperature (IAT) sensor voltage. If voltage is greater than 4.5 volts, go to step 4). If voltage is 4.5 volts or less, wiggle IAT sensor harness while observing DRB-II display. If voltage changed while harness was wiggled, repair harness where wiggling caused change. Perform TEST VER-1.

2. If wiggling harness did not cause a voltage change, condition required to set fault is not present at this time. INTAKE AIR TEMP SENSOR VOLTAGE HIGH fault sets if IAT sensor circuit voltage is greater than 4.5 volts. Possible causes are: sensor circuit open, sensor open internally or sensor ground wire open.

3. Inspect all related wiring and connectors. Repair wiring and connectors as necessary. Perform TEST VER-1. If no problems were found with wiring and connectors, see INACTIVE FAULT CONDITION. Test is complete. Perform TEST VER-1.

4. Disconnect IAT sensor. Connect a jumper wire between IAT sensor connector terminals, signal circuit (Black/Red wire) and ground circuit (Black/Light Blue wire). Using DRB-II, read IAT sensor voltage. If voltage is less than one volt, replace IAT sensor. Perform TEST VER-1. If voltage is one volt or more, move jumper wire from IAT sensor connector, ground circuit (Black/Light Blue wire) to engine ground.

5. Using DRB-II, read IAT sensor voltage. If voltage is less than one volt, repair open ground wire. Perform TEST VER-1. If voltage is one volt or more, turn ignition off. Disconnect Powertrain Control Module (PCM).

6. Using external ohmmeter, check resistance of IAT sensor signal circuit (Black/Red wire) between IAT sensor connector and PCM connector terminal No. 21. If resistance is 5 ohms or more, repair open Black/Red wire. Perform TEST VER-1. If resistance is less than 5 ohms, replace PCM. Perform TEST VER-1.