Yet another electrical gremlin.

steveskeggy

Active Member
Joined
Jul 4, 2011
Messages
172
Car
S55 AMG
Having sorted most of the other electrical gremlins on my S55 AMG W220, I am down to the last major one.
It has the check engine light on the dash, reading the codes gives me P2023 Secondary air pump relay 0410.
The additional info gives that signal not present.
if we use standard relay numbering, I have checked the relay (N) socket, there is power to pin 30, as there should be.
If I start the engine and put a meter across pins 85 and 86, it reads 12v, as it should.
If I put a relay into the socket, and manualy push the contact across, it runs the pump.
But, if I leave the relay in the socket (I checked the relay, and it works fine), it does not pull the contact across, and does not trigger the pump.

Thats with a standard A0025421319 relay, which is a common relay for the car.
I understand that the air pump uses its own special relay, and the 1319 may not be up to the job, but I would have thought it would at least trigger.
The part number for the correct relay for the secondary air pump is A0025429019.
I tried ordering one from the local Mercedes main dealer, only to be told that that part is no longer available, and they could not suggest an alternative part!
I cant even find one on the internet, the only listings are on Russian sites, and although they list them, they dont seem to sell them.
The 500 4matic uses the same relay, but the rest of the range seems to use the 1319 relay including the non-supercharged S55, and it looks like the W221`s use the 1319 as well.

Does anyone know a proper alternative to this relay, or can tell me where to get one?
Can anyone think why the good 1319 relay wont work in the socket?

Thanks
Steve
 

Riva811

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CL500 Blueefficiency
0986332040 Bosch

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steveskeggy

steveskeggy

Active Member
Joined
Jul 4, 2011
Messages
172
Car
S55 AMG
OK thanks, I will get one ordered.
Further to earlier, I have found out that the ground side of the relay seems to be faulty.
If I jump a ground wire to pin 86 (or it could be 85) the relay triggers, and the pump works.
However it starts before the engine is running, when the key is in position 2.
So, I am guessing that all the timing for the circuit is done on the negative side.
Could this be a SAM fault?
 

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