Intake Air Heater "B" Circuit Range/Performance
P2606 indicates the engine control module detected a performance or range problem with the intake air heater B circuit. This circuit preheats incoming air during cold starts to improve combustion and engine starting. The fault means the heater isn't reaching expected temperature or is responding outside normal parameters.
What You Might Notice
- Check Engine Light illuminated
- Difficult or extended cranking time during cold starts
- Engine stalls or rough idle at cold temperatures
- Engine may not start in cold weather
- Reduced fuel efficiency in cold conditions
Most Common Causes
- 1
Faulty Intake Air Heater Element
The heating element itself may be burned out, corroded, or degraded, preventing it from generating sufficient heat. This is the most common cause of this code.
- 2
Defective Heater Relay
The relay controlling power to the heater circuit may be stuck open, failing to energize the heating element properly or at the right time.
- 3
Intake Air Temperature Sensor Malfunction
A faulty temperature sensor sends incorrect readings to the PCM, causing it to fail to activate the heater or detect proper heating performance.
- 4
Corroded or Damaged Wiring and Connectors
Corrosion, loose connections, or damaged wiring in the heater circuit can interrupt power flow or create high resistance, preventing proper heater operation.
How to Diagnose It
- 1
Check Faulty Intake Air Heater Element — The heating element itself may be burned out, corroded, or degraded, preventing it from generating sufficient heat. This is the most common cause of this code.
- 2
Check Defective Heater Relay — The relay controlling power to the heater circuit may be stuck open, failing to energize the heating element properly or at the right time.
- 3
Check Intake Air Temperature Sensor Malfunction — A faulty temperature sensor sends incorrect readings to the PCM, causing it to fail to activate the heater or detect proper heating performance.
- 4
Check Corroded or Damaged Wiring and Connectors — Corrosion, loose connections, or damaged wiring in the heater circuit can interrupt power flow or create high resistance, preventing proper heater operation.
How to Fix It
- 1
Test and Replace Intake Air Heater Element
Use a multimeter to test the heater element for continuity and resistance. If open or out of specification, remove and replace the heater element assembly. Confirm proper installation and electrical connections.
- 2
Inspect and Replace Heater Relay
Test the relay with a multimeter or swap with a known good relay to confirm operation. Replace if faulty, ensuring proper seating in the relay socket.
- 3
Repair Wiring and Connectors
Inspect all wiring and connectors in the heater circuit for corrosion, damage, or loose connections. Clean corroded terminals with electrical cleaner, repair damaged wiring, and reseat all connectors securely.
- 4
Test and Replace Intake Air Temperature Sensor
Use a scan tool to monitor sensor voltage across temperature ranges or swap with a known good sensor to isolate the fault. Replace the sensor if readings are inconsistent or out of range.
Need a deeper diagnosis?
Search for related repair guides or browse by system.