My 2000 ML430 had the CEL light come on and threw code p0410 (Secondary Air Injection). Also the Secondary Air Injection 40 amp fuse was blown. I just had the brake fluid replaced, not that it's related but I wonder if a part of the engine was damaged while replacing it. The vehicle seems to run good, despite the CEL. Any suggestions?

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Steve32

Since air injection is an EMISSION warm-up system you shouldn't notice any runing problem.... Replace fuse/erase code & wait till tomorrow & see if the pump runs then.

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MERCEDES Benz Master Guild Technician (6 TIMES)
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190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

CEL is back. Fuse is not blown this time and scan indicates code 410 again. Any ideas?

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Steve32

There are at least 5 possibilities!

The air pump MUST run.
The air pump diverter switch-over valve must receive signal & open.
The air injection diverter valves must get vacuum from the switch-over valve.
The diverter valves must open allowing air into the exhaust.
The front oxygen sensors must se that oxygen & react by dropping their output to almost no signal.

Scanners that have a activation feature can perform those needed tests!

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Determined to resolve this issue I decided to check the fuses and found the following:

-Fuse F14 (25A), which is listed as (Diesel) Injection System had a 15A fuse in same and was blown. I replaced with the proper 25A fuse, although I don't know if this fuse is functional, as the ML430 is not a diesel.

-Fuse F40 (20A), which is listed as the Vacuum Pump was missing, which I replaced.

-Fuse F44 (30A), which is listed as Air Conditioner Blower had a 30A fuse in same and was blown. I replaced with the proper 30A fuse, however with the winter months, I have not been using and the air which worked fine over the summer.

I'm sure in some way these findings contributed to the CEL and code p0410, but am looking for some definitive feedback. I never had CEL issues before and never checked all the fuses. Also will the CEL reset itself, provided the new fuses resolve the problem, or do I need to reset it through the scanner? Anyone?

__________________
Steve32

Do you now hear the AIR PUMP run in the morning??? hood open & engine COLD...

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator