P1799

DTC P1799: Problem in Intake Air Temperature Sensor Circuit

NOTE: Record all freeze data and review General Troubleshooting Information before you troubleshoot.

1. Turn the ignition switch ON (II).
2. Check whether the OBD II scan tool indicates code for the intake air temperature (IAT) sensor.
Does the OBD II scan tool indicate code for IAT sensor?
YES-Do the DTC Troubleshooting for the IAT sensor circuit low voltage, and the IAT sensor circuit high voltage. Recheck for DTC P1799 after troubleshooting.
NO-Turn the ignition switch OFF, then go to step 3.
3. Disconnect TCM connectors A (26P) and B (22P).
4. Turn the ignition switch ON (II).





5. Measure the voltage between TCM connector terminals B20 and A4 or A17.
Is there 4.75 - 5.25 V ?
YES-Go to step 6.
NO-Repair open or short in VREF wire between TCM connector terminals B20 and the ECM.





6. Measure the voltage between TCM connector terminals B19 and A4 or A17.
Is there 0.1 - 4.8 V?
YES-Check for loose terminal fit in the TCM connectors. If necessary, substitute a known-good TCM and recheck.
NO-Repair open or short in the wire between TCM connector terminal B19 end the IAT sensor..