P2003 P0410 W211.065 E320 2002 Secondary Air Injection Malfunction

[Driver41]

Hello Xulfiqar bhai, @Xulfiqar

I got this Mercedes 211.065 WDB2110651A040807.pdf (52.4 KB)

Purchased it at 55k Km, now it around 63km Km.

Fuel average is around 9.5 / 10 kmpl.

Changed Gear oil by 236.10, gear oil filter, ac filter (inside one and outside ones), air filter, engine oil.

Replaced steering rack solenoid valve (steering was bit stiff before, now it is much better).
Replaced 4 wheels brake pads and sensors.
Inspected timing belt, no sign of wear.

Car is good overall.

But there is one problem and it is not resolving, checked multiple workshops but nothing yet.

There is this error code P2003 P0410 Malfunction of Secondary air injection. So far i have done following things:
1. Smoke test to check any leak , result = no leak found
2. Visual inspection of all hoses = all good, no hardened hoses, or cracked hoses, all good
3. Cleaning of sensor near valve
4. Replacement of Secondary Air Pump and Air Switch valve
5. Replacement of valve seal for any possible oil leak and going inside (breather)

6. Checking for current in Secondary air pump and switch valve

All this work done but this check light comes back after driving for around 300km. Car is not sluggish or any issue, fuel average at mix speed of 100-140km cruising is around 9.5kmpl.

Can you please guide me on how to resolve this issue? My electrician is saying we need to replace complete Intake Manifold because it is leaking oil which is causing this check light.

My Engine oil level is still showing Ok in cluster. Last I replaced 8 liter and have driven around 8000 km after that.

Please need your guidance in resolving this problem. It is just painful to see this check light popping in.

Many thanks,

[Xulfiqar]

Hi

Please check if the secondary air injection one way diaphragms work, they are on the front edge of the cyl head connected to the air pump.

Their internal passage opens into the cyl head casting on all exhaust ports,

The troubleshooting for them is 2 steps. Let me explain, the ecu commands a function then checks for feedback. We know that there is no travel sensor on the vacuum pods so thats out

The function is conmanded by the ecu, the air pump runs (ecu can see this as a voltage sink of that transistor in it but mb doesnt care) the actual feedback is seen by the oxygen sensors. If the exhaust is running lean when the ecu commands a health check (idling at a traffic light, the startup sequence of dead cold is a long timer)

So now we have a grasp of how it works.

There are a couple of vacuum pods that lift a valve to allow air to pass, if air doesnt pass then the oxygen sensors dont change output and the ecu doesnt see the expected change and throws a code.

To fix it
Check the vacuum solenoid that connects manifold vacuum to the pods if its working (its a simple on/off)
Check if you have manifold vacuum at the vacuum solenoid, if not then your internal vacuum chamber in the manifold is leaking, dont bother opening the manifold to try and repair that, its impossible,, plumb a toyota part to the system.

Check the pods if they respond to vacuum (use a handy vacuum pump)
Blow air through the vacuum pod connections to the heads and listen or feel at the exhaust pipe to verify its working

Good luck