What Does P2604 Mean?
The PCM has detected that the intake air heater system is not performing within expected parameters. The heater may be drawing incorrect current or heating element resistance is outside specifications.
Common Causes
35%
Degraded intake air heater element with reduced resistance or partial failure
25%
Corroded or loose connections at intake air heater
20%
High resistance in power or ground circuit to intake air heater
12%
Faulty intake air heater relay or control module
8%
Low battery voltage or charging system issues affecting heater performance
Diagnostic Steps
1
Step 1: Monitor intake air heater current draw with scan tool or amp clamp during activation (compare to specifications)
2
Step 2: Measure resistance of intake air heater element with ignition off (typical range 0.3-2.0 ohms depending on design)
3
Step 3: Inspect all connections to intake air heater for corrosion, looseness, or damage
4
Step 4: Check voltage at heater during activation (should see near battery voltage); verify ground circuit continuity
5
Step 5: Test battery and charging system voltage under load to ensure adequate power supply
Estimated Repair Cost
$200 - $600
Parts + labor, varies by vehicle and location
The PCM has detected that the intake air heater system is not performing within expected parameters. The heater may be drawing incorrect current or heating element resistance is outside specifications.
The most common cause of P2604 (Intake Air Heater "A" Circuit Range/Performance) is: Degraded intake air heater element with reduced resistance or partial failure
Typical repair costs for P2604 range from $200 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Hard starting in cold weather and increased white smoke on startup. Vehicle remains drivable but may have extended cranking time in cold conditions.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2604 to identify the root cause.
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Quick Info
Category
Powertrain
System
Intake Air Heating System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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