I have been getting a code for secondary air flow for over a year. I reset the light and it stays off a couple of days to a couple months. This seems to mean it’s a intermittent failure. Then it started coming back on in just a few days. I pulled off the EGR and cleaned the tube out as other posts have mentioned. There was not much carbon but I cleaned what I could see. Now it is back to keep the light off for close to a month. MY main Question is how do I check if the EGR is working correctly and how do I clean the inside of the EGR? (If you can clean it) Could the EGR be my problem not the pump?
Any help would be appreciated I’m getting tired of messing with this but also don’t want to buy a new pump if that’s not the problem – it’s quite expensive and the car runs well either way.
Sorry this is a '96 S320

 

If this is the V6, the problem is likely the electric motor used for exhaust gas recirc. If so, search forums for your code, which iirc is po400.

 

No this is the inline 6 Thanks though.

 

BUMP

 

Rod,

Here's the group of DTCs -- which ones are you getting?

P0400 Exhaust Gas Recirculation Flow Malfunction
P0401 Exhaust Gas Recirculation Flow Insufficient Detected
P0402 Exhaust Gas Recirculation Flow Excessive Detected
P0403 Exhaust Gas Recirculation Circuit Malfunction
P0404 Exhaust Gas Recirculation Circuit Range/Performance
P0405 Exhaust Gas Recirculation Sensor A Circuit Low
P0406 Exhaust Gas Recirculation Sensor A Circuit High
P0407 Exhaust Gas Recirculation Sensor B Circuit Low
P0408 Exhaust Gas Recirculation Sensor B Circuit High
P0410 Secondary Air Injection System Malfunction
P0411 Secondary Air Injection System Incorrect Flow Detected
P0412 Secondary Air Injection System Switching Valve A Circuit Malfunction
P0413 Secondary Air Injection System Switching Valve A Circuit Open
P0414 Secondary Air Injection System Switching Valve A Circuit Shorted
P0415 Secondary Air Injection System Switching Valve B Circuit Malfunction
P0416 Secondary Air Injection System Switching Valve B Circuit Open
P0417 Secondary Air Injection System Switching Valve B Circuit Shorted
P0418 Secondary Air Injection System Relay "A" Circuit Malfunction
P0419 Secondary Air Injection System Relay "B" Circuit Malfunction


Regards,
paul...

 

Paul. I'm getting
P0411 Secondary Air Injection System Incorrect Flow Detected

 

The secondary air system has nothing to do with the EGR. You could have a vacum problem to the diverter valve which allows air to the exhaust, weak O2 sensor or a malfunctioning pump. It would help if you had a diagnositc machine that can activate the air pump and watch the up stream O2 SENSOR and see if the millivolts drop, they should drop below 40 millivots very quickly.

 

Rod,

I agree with brakel8's post, and also about having a OBD2 diags tool that can read the actual live data coming off the ECU for the various sensors and plot it. These tools run off a laptop (or Palm tool) and are around $200 -- you'll spend more than that bringing your car to a shop. Many emission sensor problems are related to vacuum leaks that are very small and difficult to find/detect.

Also, the EPA required auto companies to make the OBD2 diags info available due to the emissions requirements in the US -- you may be able to find a bootlegged copy online somewhere.

Regards,
paul...

 

Hi Guys,

Sorry to invade. I have a 2004 c220 cdi estate..
The car drove really low and as in limp mode..would not want to pick up/kick down...just steady slow drive.
Was getting the code P1400...replaced the EGR...no luck...
replaced the air mass sensor...no luck...
Now getting the codes P0472 EXHAUST PRESSURE SENSOR LOW, P0403 EXHAUST GAS RECIRCULATION CIRCUIT MALFUNCTION, P1400.

Now not sure on how to fix it now. Any help or guidance would be appreciated.