Ive got a 5A fuse in the undercowl fuse box that keeps blowing, along with it I have gotten codes:


P0418 (Secondary Air Injection System Control A Circuit- No signal/communication, test conditions are not completed, fault is currently active and causing DTC light)
P0419 (Secondary Air Injection System Control B Circuit- No signal/communication, test conditions are not completed, fault is not currently active and not causing a DTC light)
P2307 (Secondary Air Injection System Control B Circuit- Value below lower limit value, test conditions are not completed, fault is currently active and causing a DTC light)


I've already disassembled both secondary air pumps and verified they are not physically damaged (broken blades, etc). This also seems to have came about the same time my "Brake Booster Failure" notification (which came from a failed vacuum line that has been mended) has returned... Is it possible these issues are connected?


Any leads to pursue would be greatly appreciated. Thank you.

 

On the 955 the 5 amp fuse in the engine compartment is F12.

It runs the secondary air pumps control relay circuits and also the afterrun pump relay and pump.

You may have a problem with the secondary air pump control circuit or the circulation pump / circuit.

The secondary pumps themselves receive power via 40 amp fuses and would not affect the 5 amp fuse.

To test the circulation pump you can select the REST function on your climate panel after the engine is warm and confirm the pump works.

 

I would try replacing the relay for the air pumps.

 

Rest function works properly.


Will be checking that relay next.


Thanks for the tips guys

 

For future search reference, this issue has been resolved. Going on 2 weeks with no warning indicators or blown fuses, so Im feeling confident its been mended.


The problems were not related.


Issue A regarding the fuse and check engine light were resolved by replacing relay 1/4. (very many thanks Mr Haney).


Issue B regarding the re-appearance of brake booster failure light was due to a new vacuum leak which occurred in another area of the same vacuum line between the brake booster and firewall.