Intake Air Temperature Sensors, Checking
Intake Air Temperature Sensors, Checking
Intake air temperature sensor and Mass Air Flow (MAF) sensor are one component.
Special tools, testers and auxiliary items required
• Multimeter (VAG1526) or Multimeter (VAG1715)
• Connector test kit (VAG1594)
• Wiring diagram
• Chilling spray (commercially available)
Test Prerequisites
• The respective fuses of Engine Control Module (ECM) (J623) must be OK:
• The parking brake button must be engaged in order to connect the electrical parking brake.
Function Test
- Connect diagnostic tester.
- Switch ignition on.
- Under address word 33, select "Diagnostic mode 1: Checking measured values."
- Select measuring value "PID 15: Intake air temperature".
- Check specified value of intake air temperature:
* If a temperature is indicated which is below the ambient temperature of sensor, first check sensor wires for contact resistance. Note that while the vehicle is standing still the sensor might warm up due to radiant heat.
If specified value is not obtained or a fixed value is displayed, check wire connections.
- End diagnosis and switch ignition off.
If specified value is not obtained, check wire connections.
Wire Connections, Checking
- Connect test box (VAG1598/31) to wiring harness of Engine Control Module (ECM).
- Disconnect connector from Intake Air Temperature (IAT) sensor (Mass Air Flow MAF sensor connector).
The following wire connections must be checked for short circuit to B+, Ground (GND) and for open circuit
- Repair open circuit in wiring or short circuit if necessary.
- In addition, check both wires to each other for short circuit.
Specified value: infinite ohms (no continuity)
- If no malfunction was detected during the previous tests, replace Engine Control Module (ECM).
- Read readiness code => [ Readiness Code, Reading ] Monitors, Trips, Drive Cycles and Readiness Codes. If DTC memory was erased, readiness code must be generated again => [ Readiness Code, Generating ] Monitors, Trips, Drive Cycles and Readiness Codes.