P0414

What it means

P0414 means the control unit has detected a short in the circuit controlling secondary air injection switching valve A. The module drives this valve to route pumped air to the exhaust or catalyst during cold starts, and it monitors the driver circuit for abnormal current or voltage. A shorted reading, either to power, to earth or within the valve coil, sets the code.

Symptoms

• Engine warning light on
• Secondary air system not working on cold start, or the pump running at odd times
• Slightly higher cold-start emissions or a failed emissions test
• Possible hissing or no audible pump noise just after a cold start
• Usually no noticeable change in driveability

Possible causes

• Internal short in the switching valve solenoid or coillikely
• Damaged, chafed or pinched wiring to the valve shorting to earth or a supplylikely
• Corroded, wet or damaged connector terminals at the valvepossible
• Faulty relay or fuse circuit feeding the secondary air system, depending on the vehicle's wiring layoutpossible
• Fault in the control unit output driverrare
• Water or debris ingress into the valve from the air pump or pipeworkpossible

How to diagnose

1. Read stored and pending codes and freeze frame data, noting engine temperature and conditions when the fault set
2. Check for other secondary air codes, as they may point to a shared supply or pump fault
3. Visually inspect the valve connector and wiring for chafing, heat damage, water and corrosion
4. Check the relevant fuse and relay against the wiring diagram for your model
5. Measure the valve coil resistance and compare with the manufacturer's specification
6. Back-probe the valve connector and check for short to earth or to supply on the control and feed wires with the module disconnected, as per the wiring diagram
7. Command the valve with a bidirectional scan function if available and confirm it operates and that the code does not return
8. Check the valve and air pipes for water, carbon or debris if the valve fails the tests

How to fix

• Replace the secondary air switching valve if the coil is shorted or the valve is faulty
• Repair or replace damaged wiring and secure it clear of heat and sharp edges
• Clean or replace corroded connector terminals and seal the connector
• Replace a faulty relay or fuse after finding out why it failed
• Clear any water ingress and repair the source, replacing the valve if it is contaminated
• Diagnose and repair or replace the control unit only after wiring and valve faults are ruled out

Can I keep driving?

Nearby codes

• P0413GenericAIR System Switching Valve A Circuit Open
• P0415GenericAIR System Switching Valve B Circuit