P0418

DTC P0418
Secondary air pump power stage (relay) fault Drive cycle D:Signal missing.

DTC P0418
Secondary air pump power stage (relay) fault Drive cycle D:Signal out of range - above maximum.

DTC P0418
Secondary air pump power stage (relay) fault Drive cycle D:Signal out of range - below minimum.

Possible causes by suggested order of priority:
- Secondary air pump relay.
- Secondary air pump M207.
- Short Circuit C0573/1 (R) - C0879/2 (R).
- Open Circuit C0573/1 (R) - C0879/2 (R).
- Open Circuit C0879/1 (B) - C0563/1.

Secondary air pump relay.
- Check the secondary air pump relay for any faults or damage.
- Check Connector C0573/1 (R) is fitted correctly.

Secondary air pump M207.
- Check the secondary air pump for any faults or damage.
- If TestBook available, it can be used to confirm any suspected faults. Run the secondary air system diagnostic, as this will tell you if the system is operating correctly.

Short Circuit C0573/1 (R) - C0879/2 (R).
- Check resistance < 5.0 Ohm

Open Circuit C0573/1 (R) - C0879/2 (R).
- Check resistance > 1M Ohm

Open Circuit C0879/1 (B) - C0563/1.
- Check resistance > 1M Ohm