The Electronic Control Module (ECM) supplies and monitors a voltage signal (terminal 7) to one side of the Intake Air Temperature sensor (IAT). The other side of the IAT sensor is connected to a common sensor ground, which is also connected to the ECM (terminal 26).
The IAT sensor works by having a specific resistance at a specific temperature. As the resistance varies, so does the voltage on terminal 7.
At high temperatures, the sensor resistance is very low, which effectively lowers the signal voltage on terminal 7.
At low temperatures, the resistance is very high, alowing the voltage to rise close to 5 volts.
The ECM monitors this voltage to compensate for various operating conditions.
DTC P0112: IAT sensor voltage low
DTC P0113: IAT sensor open/high
You might check for:
- Poor connections on ECM and harness connector, damaged terminals, etc
- Intermittent faults "wiggle test" of wiring for poor connections
- Sensor may have become out of calibration.
The manual you are missing is the "Electrical Diagnostic Manual" for your particular model. Just like the Shop Manual, you can order one from the dealer. The electrical diagnostic manual has a table of sensor temperatures and voltages to check sensor performance.
The Delphi engine management system looks a lot like a GM car in terms of diagnostic codes. I think these IAT Diagnostic Trouble Codes are the same for my Corvette.
The manual is well worth the $$ if you have one of these Delphi bikes - pretty straight forward once you have the proper documentation.
