I like most people have now got the dreaded P0410 code. I have a plan, however I have noticed a new situation that did not give the result I would have expected. I may have missed this in all the reading I have done, so can I run it by you all to ask for comment?

known facts:-
The air pump runs as expected, the air pump can be heard to run for 20 seconds or so while the car is at first idle. NO warning light illuminates 90% of the time.
For the other 10% I will be looking at the RCM soldered joints and relays, the main 40A fuse, the earth connector on the motor, the power connector to the motor etc etc.

I have made an assumption that the P0410 error can be triggered by the air pump being seized up, a bad earth connection or a poor power connection. The logic would also indicate that if the earth was missing (broken wire) or the power supply was poor (oxidisation, broken wire, bad RCM) the P0410 code would be set.

Therefore if I disconnect the earth and power connectors from the air pump and fire her up the P0410 code should be set. Not in my case, no code is being set.

Can anybody explain this? Does anybody know what logic is being used to set the code?

Cheers

 

Just a guess O2 sensors and temperature of engine coolant.

 

I have started to pull things apart and am fixing as I go along. By this I mean:-

1. Air pump earth oxidised, therefore a potential bad earth. All cleaned up. Fitted a crinkle washer to ensure bolt and earth tag are fully bonded together. Tested and good earth point present. Cranked engine no P0410 code set.
2. Air pump power connector oxidised, again a source for poor contact. All cleaned up and refitted. Cranked engine no P0410 code set.

Been for a short drive, no P0410 code set.

Now moved onto the Vacuum Solenoid (item 13 on the air pump drawing). I appreciate that this may have nothing to do with the P0410 issue, but I noticed the power cable to this unit was blocking the "breather pipe" and also a hard foul on the engine body. Perhaps the reduced airflow into this unit is the issue or perhaps the cable has become damaged and is shorting out?

 

THe criteria that determine when the ECU will run the pump is not clear to me. I don't always hear the pump on startup.
You can google "Secondary AIr Injection" and learn WHY it runs and what the criteria are, but like me, you will probably find conflicting information.

My understanding:
The pump is run in order to add air (which means you add more oxygen) to the exhaust gasses, this helps cause a reaction in the cats that helps them heat up faster (they do their job better when hot).
The ECU 'knows" if the pump runs and does it's job by seeing an increase in O2 level via oxygen sensors in the exhaust.
If the ECU 'gets the idea' that the cats are already probably hot, it won't run the pump - but I don't know how it comes to that conclusion, other than monitoring water temperature, or maybe it has a memory of how long it's been since the engine last ran or maybe if the ambient or intake air temp is over a certain temp. Hard to say, but I do know that my pump does not always run on startup even with a cold engine.

 

[QUOTE=pizzaguy;972959]THe criteria that determine when the ECU will run the pump is not clear to me. I don't always hear the pump on startup.

Do you think it's a fair assumption that the pump would run on a typical cold damp British day ie low 50's?

 

[QUOTE=THETESTER;972968]

On initial startup, yes. BUT if warmed up and not sitting for too long (where pressure may drop after a period of time), no. If you suspect a drop in pressure, then get the test done at the schrader port on the fuel rail. Otherwise, hunt and peck for a solution (used to be called and still is 'the shotgun' method), that usually costs a lot more in the long run. Good Luck!


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