Secondary Air Injection System Control Circuit Low
The P2257 code indicates that the Powertrain Control Module (PCM) has detected a low voltage condition in the control circuit of the secondary air injection system. This system pumps fresh air into the exhaust to reduce emissions during cold starts. A low circuit condition typically points to a short to ground, open circuit, or a faulty relay or pump.
1. Most Common Causes
- Blown fuse for secondary air injection system
- Faulty secondary air injection pump relay
- Short to ground in control circuit wiring
- Failed secondary air injection pump
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Increased emissions during cold start
- Possible rough idle or hesitation on cold start
3. Step-by-Step Diagnosis
Step 1: Use a scan tool to verify the code and check for related codes.
Step 2: Inspect the secondary air injection system fuse and replace if blown.
Step 3: Test the relay and pump control circuit for shorts or opens using a multimeter.
Step 4: Check the pump itself for proper operation and replace if faulty.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, but the vehicle may fail emissions testing and the Check Engine Light will stay on. It's best to repair promptly to avoid potential catalytic converter damage.
How much does it cost to fix?▼
Typically $50-$150 for diagnosis and repair, but costs can vary if the pump or relay needs replacement.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.