What Does P2257 Mean?
The PCM has detected a low voltage condition on the Secondary Air Injection (AIR) system control circuit A. The control circuit voltage is below the minimum threshold required to activate the air injection pump or valve.
Common Causes
30%
Shorted to ground in AIR pump or valve control circuit wiring
25%
Failed AIR pump relay with internal short
20%
Faulty AIR pump motor with short circuit
15%
Damaged or corroded AIR system connector or ground connection
10%
PCM driver circuit failure
Diagnostic Steps
1
Step 1: Locate and inspect secondary air injection pump relay and check for proper operation
2
Step 2: Disconnect AIR pump and measure resistance to ground on control circuit (should be high resistance)
3
Step 3: Check for battery voltage at AIR pump when commanded on by scan tool
4
Step 4: Inspect all wiring and connectors in AIR system for damage, corrosion, or shorting to ground
5
Step 5: Test AIR pump motor resistance and operation with direct power application if circuits test normal
Estimated Repair Cost
$150 - $600
Parts + labor, varies by vehicle and location
The PCM has detected a low voltage condition on the Secondary Air Injection (AIR) system control circuit A. The control circuit voltage is below the minimum threshold required to activate the air injection pump or valve.
The most common cause of P2257 (Secondary Air Injection System Control "A" Circuit Low) is: Shorted to ground in AIR pump or valve control circuit wiring
Typical repair costs for P2257 range from $150 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is completely safe to drive. Secondary air system only operates during cold starts to reduce emissions during warm-up period.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2257 to identify the root cause.
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Quick Info
Category
Powertrain
System
Emissions Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
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