Fuse and Relay Location for Secondary Air Pump
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From: 🇨🇦
W463 G550 / C190 GTC //prev: W204 C63 507 / R170
Fuse and Relay Location for Secondary Air Pump
Can anyone tell me which 40A fuse and which relay control the Secondary Air Injection pump?
The dealer's technician believes my relay or pump are faulty and that's what's been giving me the occasional misfire and check air injection system warning lights.
A new pump and relay are on order, but I may need to pull the fuse if it misfires again.
I suppose this makes sense as a root cause for my issues - if the pump is running when it shouldn't be, it will lean out the mixture and cause a misfire?
The dealer's technician believes my relay or pump are faulty and that's what's been giving me the occasional misfire and check air injection system warning lights.
A new pump and relay are on order, but I may need to pull the fuse if it misfires again.
I suppose this makes sense as a root cause for my issues - if the pump is running when it shouldn't be, it will lean out the mixture and cause a misfire?
Super Member
Joined: Dec 2012
Posts: 600
Likes: 6
From: Bay Area
2010 C63 P31 AMG
Can anyone tell me which 40A fuse and which relay control the Secondary Air Injection pump?
The dealer's technician believes my relay or pump are faulty and that's what's been giving me the occasional misfire and check air injection system warning lights.
A new pump and relay are on order, but I may need to pull the fuse if it misfires again.
I suppose this makes sense as a root cause for my issues - if the pump is running when it shouldn't be, it will lean out the mixture and cause a misfire?
The dealer's technician believes my relay or pump are faulty and that's what's been giving me the occasional misfire and check air injection system warning lights.
A new pump and relay are on order, but I may need to pull the fuse if it misfires again.
I suppose this makes sense as a root cause for my issues - if the pump is running when it shouldn't be, it will lean out the mixture and cause a misfire?
MBWorld Fanatic!
Joined: Oct 2012
Posts: 3,704
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From: Denham Springs,LA
'12 C63 Black Series, '12 ML350 BlueTech
Can anyone tell me which 40A fuse and which relay control the Secondary Air Injection pump?
The dealer's technician believes my relay or pump are faulty and that's what's been giving me the occasional misfire and check air injection system warning lights.
A new pump and relay are on order, but I may need to pull the fuse if it misfires again.
I suppose this makes sense as a root cause for my issues - if the pump is running when it shouldn't be, it will lean out the mixture and cause a misfire?
The dealer's technician believes my relay or pump are faulty and that's what's been giving me the occasional misfire and check air injection system warning lights.
A new pump and relay are on order, but I may need to pull the fuse if it misfires again.
I suppose this makes sense as a root cause for my issues - if the pump is running when it shouldn't be, it will lean out the mixture and cause a misfire?
Thread Starter
MBWorld Fanatic!
Joined: Jun 2014
Posts: 2,030
Likes: 434
From: 🇨🇦
W463 G550 / C190 GTC //prev: W204 C63 507 / R170
Right, but if the air pump stays on when it shouldn't (either because the relay is stuck open or the pump is somehow defective), then you can have a misfire because the engine control computer thinks the engine is running too rich (it senses the extra oxygen in the exhaust), so it leans the engine to compensate. It gets overly lean and cylinders start to cut out.
That's my understanding anyway.
That's my understanding anyway.
