DTC P0112: IAT SENSOR VOLTAGE LOW Dodge Ram Wagon B1500

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For circuit identification and wiring diagram, see RAM VAN & RAM WAGON wiring diagram in WIRING DIAGRAMS article.

Note. DTC P0112: IAT SENSOR VOLTAGE LOW is monitored with ignition on and battery voltage more than 10.4 volts. DTC may be stored in Powertrain Control Module (PCM) when PCM senses Intake Air Temperature (IAT) sensor voltage is less than .08 volt. Possible causes are: defective IAT sensor, defective PCM, defective connectors or defective wiring.

Scheme 27

1. Turn ignition on, with engine off. Using scan tool, read IAT sensor voltage. If voltage is less than.5 volt, go to next step. If voltage is.5 volt or more, go to step 6).
2. Turn ignition off. Disconnect IAT sensor connector. (Scheme 27) Clean and/or repair connector as necessary. Turn ignition on, with engine off. Using scan tool, read IAT sensor voltage. If voltage is more than 4 volts, replace IAT sensor. Perform TEST VER-5A. If voltage is 4 volts or less, go to next step.
3. Turn ignition off. Ensure IAT sensor connector is still disconnected. Disconnect PCM connectors. PCM is located in engine compartment. See PCM LOCATION table under SYSTEM DIAGNOSTICS. Clean and/or repair connectors as necessary. Using an ohmmeter, check resistance between ground and IAT sensor connector, signal circuit (Black/Red wire). If resistance is less than 5 ohms, repair signal circuit for short to ground. Perform TEST VER-5A. If resistance is 5 ohms or more, go to next step.
4. Ensure ignition is off. Ensure IAT sensor and PCM connectors are still disconnected. Using ohmmeter, check resistance between IAT sensor connector, signal circuit (Black/Red wire) and sensor ground circuit (Black/Light Blue wire). If resistance is less than 5 ohms, repair signal circuit for short to sensor ground circuit. Perform TEST VER-5A. If resistance is 5 ohms or more, go to next step.
5. At this time, PCM is assumed to be defective. Replace PCM. Perform TEST VER-5A.
6. Turn ignition on, with engine off. Wiggle IAT sensor connector and wiring harness while monitoring IAT sensor voltage. If voltage changes while wiggling connector and wiring harness, repair connector or wiring harness that caused voltage to change. Perform TEST VER-5A. If voltage does not change, go to next step.
7. Turn ignition off. Visually inspect related connectors and wiring harness for damage. Repair connectors and wiring harness as necessary. Perform TEST VER-5A. If connectors and wiring harness are okay, go to next step.
8. Ensure ignition is on, with engine off. Using scan tool, read and record FREEZE FRAME data. Ensure CAUSED BY DTC matches DTC on DTC screen. If DTC matches, road test vehicle under conditions in FREEZE FRAME data. Using scan tool, read DTCs. If DTC P0112: IAT SENSOR VOLTAGE LOW returns, visually inspect related connectors and wiring harness for damage. Repair connectors and wiring harness as necessary. Perform TEST VER-5A. If DTC P0112: IAT SENSOR VOLTAGE LOW does not return, see «INACTIVE DTC CONDITION»(ref-139160-S32382818132002042600000). Test is complete.