Volvo All Engines (2010 Emissions) Fault Code: SPN 729 FMI 4 PID: SID 70 Intake Air Heater (IAH) 1

The preheat function is used to warm up the inlet air during cold conditions both before and after cranking to make the starting easier and better for the environment at very low temperatures. This diagnostic trouble code (DTC) detects a faulty preheat function.

Conditions for diagnostic trouble code (DTC):
1) Preheating requested
2) The voltage at pin A14.EB:7 is less than 29?% of the battery voltage

Observable symptoms
1) Intake air heater (IAH) does not function
2) White smoke at cold start
3) Difficult to start in extreme cold

Probable cause
1) Wiring harness
2) Connector
3) Intake air heater (IAH) relay