What Does P041F Mean?
The PCM has detected a low voltage condition on the secondary air injection switching valve A circuit. The control signal voltage is below the expected threshold, indicating the circuit may be shorted to ground or the valve solenoid has excessively low resistance. The AIR system cannot properly operate switching valve A during cold-start emissions reduction. The check engine light will be on with no noticeable driveability impact.
Common Causes
35%
AIR switching valve A signal wire shorted to ground
30%
Internally shorted switching valve A solenoid with low resistance
20%
Connector pin-to-ground short due to moisture or contamination
15%
PCM output driver pulling the line low inappropriately
Diagnostic Steps
1
Monitor the AIR switching valve A circuit voltage on the scan tool. With the system not commanded, the circuit should not be actively grounded by the PCM.
2
Disconnect the valve A connector and measure solenoid resistance — spec is typically 20-40 ohms. Readings below 10 ohms indicate a partially shorted coil.
3
With the valve disconnected, check the control wire for short to ground from the harness connector side. Use a multimeter to measure resistance from the signal wire to chassis ground — should be OL (infinite).
4
Inspect the wiring harness routing, especially near the exhaust manifold where heat can melt insulation and cause the wire to contact the engine block or exhaust components.
5
If the wiring and valve test good, check the PCM output by measuring voltage at the PCM connector pin for the valve A circuit. If the PCM is pulling the line low with the system off, the PCM driver may be failed.
Estimated Repair Cost
$120 - $450
Parts + labor, varies by vehicle and location
The PCM has detected a low voltage condition on the secondary air injection switching valve A circuit. The control signal voltage is below the expected threshold, indicating the circuit may be shorted to ground or the valve solenoid has excessively low resistance. The AIR system cannot properly oper...
The most common cause of P041F (Secondary Air Injection System Switching Valve "A" Circuit Low) is: AIR switching valve A signal wire shorted to ground
Typical repair costs for P041F range from $120 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving. The AIR system only affects cold-start emissions and has no impact on engine performance. The vehicle will fail emissions testing with this code set.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P041F to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Powertrain
System
Emission Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
