P2609
Intake Air Heater System Performance
The intake air heater system did not raise intake temperature by the expected amount during cold-start support. Suggests low current draw, poor connection to the grid, or a failed temperature feedback path.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- High-resistance battery feed to the heaterCommon
- Intake air temperature sensor reads with offsetPossible
Parts involved
- Intake Air Heater
- Intake Air Temperature Sensor
- Heater Relay
P2609 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.