How does the secondary air pump work on a Mercedes Benz?
On start up from cold the secondary air pump relay ‘N’ is commanded to close, this applies voltage to the air pump DC motor protected by a 40A fuse, Fuse 31. At the same time the electrical solenoid controlling the check valve vacuum is energised, allowing vacuum to pull open both diaphragm caps.
What is the contact rating of the Mercedes air pump?
The relay is rated at 35/40A and the current drawn by the secondary air pump under full load can be as high as 35A which as an inductive load pushes the relay to it maximum as far as contact rating is concerned. Once the silver contact area of the relay has deteriorated unreliable operation will result.
Where are the fuses in a s CL Class W220?
Fuses 1 though 27, Relays A B C D E F G H I J : are in the engine compartment left side / driver side. Open the hood and look next to the hood hinge on the drivers side. Remove the black plastic cover and you will see these fuses. Fuses 28 through 49, Relays O N M L K are in the engine compartment on the right / passenger side.
How to disable secondary air injection in a Mercedes Benz?
The way to disable the system is to remove and plug the single vacuum outlet (the base of the clear thin pipe to the left in the picture above) from the control solenoid to the air check valves, one either side of the v6,v8 and v12 variants, then simply pull the control relay from the right hand fuse board in the engine compartment.
On start up from cold the secondary air pump relay ‘N’ is commanded to close, this applies voltage to the air pump DC motor protected by a 40A fuse, Fuse 31. At the same time the electrical solenoid controlling the check valve vacuum is energised, allowing vacuum to pull open both diaphragm caps.
The relay is rated at 35/40A and the current drawn by the secondary air pump under full load can be as high as 35A which as an inductive load pushes the relay to it maximum as far as contact rating is concerned. Once the silver contact area of the relay has deteriorated unreliable operation will result.
How to check secondary air injection in Mercedes?
Here is some info on the conditions that are required to be met for a check to be made by the ECU/ECM. It is worth noting that it takes faults to be detected on two engine start/run cycles for the engine management lamp to illuminate on the dashboard. Mercedes – Secondary air injection pump.
Fuses 1 though 27, Relays A B C D E F G H I J : are in the engine compartment left side / driver side. Open the hood and look next to the hood hinge on the drivers side. Remove the black plastic cover and you will see these fuses. Fuses 28 through 49, Relays O N M L K are in the engine compartment on the right / passenger side.