Intake Air Temperature (IAT) sensor, checking: Notes

Recommended special tools and equipment 

• V.A.G 1526 multimeter or V.A.G 1715 multimeter
• V.A.G 1594 connector test kit
• Wiring diagram
• Chilling spray (commercially available)

Requirements 

• The respective fuses of Diesel-Direct fuel injection system must be OK:

Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations

• Battery voltage must be at least 11.5 volts.
• For vehicles with automatic transmission, selector lever must be in position -P- or -N-.
• Parking brake must be engaged.
• Ground (GND) connections between engine and chassis must be OK.

• Ignition is switched off.

Function test 

• Connect diagnostic tester. Refer to Diagnostic tester, connecting 
• Switch ignition on.
• Under address word 33, select "Diagnostic mode 1: Check measured values."
• Select measuring value "PID 15: Intake air temperature".

• Check specified value of intake air temperature:

PID		Diagnostic text		Specified value:
15:		Intake Air Temperature (IAT)		approx. ambient temperature1)

1) 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 a substitute value of approx. 134 ° C is displayed:

• Check resistance at Intake Air Temperature (IAT) Sensor -G42-. Refer to Intake Air Temperature (IAT) sensor, checking  .

If specified value is not obtained:

• Check Intake Air Temperature (IAT) Sensor -G42-. Refer to Intake Air Temperature (IAT) sensor, checking  .