Powertrain
generic / SAE
P0418
Secondary Air Injection System Relay "A" Circuit Malfunction
General electrical fault in the secondary air injection pump relay A circuit. Without the relay, the air pump cannot be commanded and the system cannot complete its cold-start function.
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number4 / 18
Possible causes
- Air pump relay failed high
- Wiring or connector fault medium
Inspection / repair
- Difficulty: easy
- DIY: possible
- Estimated cost: 40–300 €
- Estimated time: 0.3–1.5 h
- Component: secondary air relay
- Component: secondary air pump
- Component: relay wiring
- MIL / check engine light
- emissions-relevant
- drive cycle required
Sources
References
sae:J2012