P0414

Code

Generic P — Powertrain

AIR System Switching Valve A Circuit Shorted

Brand: Generic

Type: P — Powertrain

Views: UK: 29 EN: 42 RU: 38

AI status

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Page language: EN

Causes

Damaged/shorted wiring harness to AIR switching valve (chafing, pinched, rodent damage)
Corroded or loose connector terminals
Failed AIR switching valve (solenoid) with internal short
Blown fuse or failed relay related to AIR system
Incorrect aftermarket wiring/equipment tied into the circuit
PCM/ECM driver transistor failure or internal short

Symptoms

Malfunction Indicator Lamp (MIL) / Check Engine Light ON
Possible failed emissions test (increased NOx/HC)
Little or no noticeable change in driveability on many vehicles
Possible rough idle or hesitation if AIR system affects combustion

What to check

Read and record freeze-frame data and related codes (P0410–P0416)
Visually inspect wiring and connector for the AIR switching valve A for damage, corrosion, or pinching
Check related fuses and relays for the AIR/secondary air system
Backprobe valve connector and observe control signal with key on / engine running
Measure valve coil resistance with connector disconnected (key OFF)
Perform a wiggle test on harness/connectors while monitoring the circuit

Signal parameters

Control signal: typically either switched 12 V or a PCM-switched ground/pulsed output when active (varies by vehicle)
OFF state: control circuit should read near open/high impedance or battery voltage depending on circuit topology
ON state: control circuit may show pulsed or steady voltage; observe expected switching behavior with scope
Coil resistance: typically a low value (few ohms to a few tens of ohms); exact spec varies by vehicle—consult service data
Current draw: coil will draw measurable current when energized; abnormal high or near short-level current indicates internal failure

Diagnostic algorithm

Retrieve all stored codes and freeze-frame data. Note if other AIR-related codes are present.
Visually inspect the AIR switching valve A connector and wiring harness from valve to PCM for damage, corrosion, or aftermarket modifications.
With ignition OFF, disconnect the valve connector and measure coil resistance between valve terminals. Compare to service spec or expect low-ohm value; an almost zero ohm reading suggests internal short.
Check for short to battery or ground: with connector disconnected and ignition OFF, measure resistance from the harness control pin to battery positive and to chassis ground. Low resistance to either indicates wiring short.
Check fuses and relays in the AIR/secondary air circuit. Replace any blown fuses and retest.
With backprobe and key ON (engine off) or engine running as required, measure control voltage at the harness connector and observe behavior when command is given by the scan tool. Use an oscilloscope for pulsed signals.
Perform a wiggle test on wiring while monitoring the circuit and MIL to locate intermittent shorts or opens.
If wiring checks good and valve coil resistance/spec are out of range or behaves like a short, replace the AIR switching valve A.
If valve and harness are good, suspect PCM output driver fault—verify with manufacturer procedures before replacing PCM.
Clear codes, run the vehicle through drive cycle or re-test conditions and confirm the fault does not return.

Likely causes

Shorted/grounded wire in valve control circuit (most common)
Failed switching valve coil
Corroded connector or poor contact causing short
PCM output stage fault (less common)

Fault status

⚠️ Status

P0414 — AIR (Secondary Air Injection) System Switching Valve A Circuit Shorted: PCM detected an abnormal short/low resistance in the control circuit. Check valve, wiring, connectors, fuses/relays, and PCM output.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5 - 2.5 hours