The P2257: Secondary Air Injection System Control ‘A’ Circuit Low code indicates that there is a low voltage or signal in the secondary air injection system control ‘A’ circuit. This could be due to faulty control modules, wiring issues, or problems with the connectors, and it impacts the ability of the secondary air injection system to function properly. This system helps reduce emissions during engine warm-up, and a fault here can lead to increased exhaust emissions.
P2257 – Quick Overview
| Code | Information |
|---|---|
| Meaning | P2257: Secondary Air Injection System Control ‘A’ Circuit Low |
| Is it serious? | Yes, as improper function of the secondary air injection system can lead to increased emissions and failure to meet environmental regulations. |
| Possible causes | – Low voltage or signal in secondary air injection system control ‘A’ circuit – Faulty control module – Wiring issues – Connector problems |
| How to diagnose? | – Measure voltage in the secondary air injection system control ‘A’ circuit – Test the control module and associated components – Inspect wiring and connectors for faults |
P2257 Meaning
The P2257: Secondary Air Injection System Control ‘A’ Circuit Low code indicates that there is an issue with the voltage or signal in the secondary air injection system control ‘A’ circuit. The secondary air injection system is responsible for introducing air into the exhaust to help burn off excess emissions during cold starts, and it is controlled by a circuit connected to a control module. A low voltage in this circuit can indicate that the system is not functioning as intended, leading to increased emissions.
Step-by-step diagnostic guide
| Action | Description | Tools Needed |
|---|---|---|
| Check for Other Codes | Use an OBD-II scanner to determine if there are any other related codes. These codes can provide additional context on whether the issue is isolated or part of a broader system failure. | OBD-II Scanner |
| Measure Voltage in the Secondary Air Injection System Control ‘A’ Circuit | Use a multimeter to measure the voltage in the secondary air injection system control ‘A’ circuit. Compare the reading with the manufacturer’s specifications to determine if the voltage is lower than required. | Multimeter, Vehicle Service Manual |
| Test the Control Module and Associated Components | Use a diagnostic scanner to test the functionality of the control module responsible for managing the secondary air injection system. Verify that the module is working correctly and outputting the necessary control signals. If the control module fails the test, it may need replacement. | Diagnostic Scanner |
| Inspect Wiring and Connectors for Faults | Visually inspect the wiring and connectors associated with the secondary air injection system control ‘A’. Look for loose connections, corrosion, or damaged wiring that might cause low voltage in the circuit. Repair or replace any damaged components. | Flashlight, Safety Gloves |
| Check the Air Pump and Valves | Inspect the secondary air injection air pump and check valves to ensure they are not malfunctioning. A faulty pump or valve may affect the system’s ability to generate the necessary air flow, which can trigger a low signal condition. | Basic Hand Tools |
| Clear the Code and Test Drive | After repairing any faults, use an OBD-II scanner to clear the code. Conduct a test drive to ensure that the secondary air injection system is functioning correctly and that the P2257 code does not return. | OBD-II Scanner, Vehicle Owner’s Manual |
| Recheck for Codes | Re-scan the vehicle to confirm that the P2257 code has not returned. If the code persists, additional diagnostics may be necessary to determine the underlying problem in the system or circuit. | OBD-II Scanner |
Free PDF: How to choose OBD2 scanner
I’ve made you a free PDF to choose the OBD2 scanner in 5 minutes.
✅ Which OBD2 scanner is best?
✅ Which type should you get (DIY, Pro, Hobby)
✅ What is the best scanner for the exact brand/feature (e.g best for BMW)
✅ How to get a Bi-Directional tool for as cheap as $40
✅ Discount coupons for scanners
PDF is 100% free and it is designed to help you pick a scanner in less than a few minutes! Not a boring 50-page guide.
Just tell me where to send it.
Hi, I am Juraj “Yuri” Lukacko. I got frustrated by unhelpful and scammy mechanics, so I decided to learn everything about car diagnostics myself. I test dozens of new car diagnostic tools every month along with learning new strategies to fix and customize cars. About Juraj Lukacko (Yuri)