fault codes

**Big Knox** · 20th January 2011, 11:53

P0400 - Exhaust Gas Recirculation Flow Insufficient Detected
(5A) - Present
P0621 - Generator Lamp "L" Control Circuit Malfunction
(01) - Present

P0400 is EGR so just wondering how much success people have with cleaning it? Am I just delaying the inevitable replacement or does it actually bring the EGR valve back to life?

P0621 I think is related to the alternator. I replaced my alternator a few months ago after the original died so hope I don't need another one. No battery lamp on the dash though. Anyone got any thoughts on the above code?

Cheers.

PS I have 1.9 CDTi [150]

**Big Knox** · 20th January 2011, 20:56

**dh.dti** · 20th January 2011, 21:20

I haven't even removed mine on my cdti yet, i did on my preface dti & it made a big difference...
If your running around with that code present it certainly won't do any harm to strip it & clean etc...

**Big Knox** · 23rd January 2011, 14:28

this is my task for this afternoon. Going to pop to halfrauds and get some carb cleaner and then give the EGR and boost sensor a skoosh

**durham4416** · 23rd January 2011, 14:52

Could the alternator code just be a stored fault that wasn't deleted?

**djr69uk** · 23rd January 2011, 16:08

Regarding the P0621. I've read that some replacement alternators can throw this up. It happened after I got mine replaced a year ago. You don't get EML or spanner light, just the stored fault right? If so... my advice, as long as the glow plugs are working and you get GP light on for few seconds first thing in the morning as normal... then just ignore it. It doesn't seem to cause any problems.

With regard to the EGR. Strip and clean as per the 'how 2'. You are essentially servicing this item and as long as you do it semi regularly (I do mine about every 6 months), then it should last.

**djr69uk** · 23rd January 2011, 16:13

Taken from another forum post...

P0621 - "This happens if you fit the wrong alternator. On older types the L circuit was simply connected straight to the warning lamp. On a Canbus car it goes to the ECU which controls the warning light. I am guessing your alternator does not comply with Canbus.

This is a known problem when fitting an aftermarket alternator. Not all of them are correctly listed!"

I'd ignore it chap. I have been lol!

**Big Knox** · 23rd January 2011, 17:00

yeah, not sure if the alternator is throwing up the fault. The spanner light then the EML light came on and when I put OP-COM on the car, the two faults came up together so I'm assuming perhaps the EGR is the cause of the lights and the alternator one might be from the past.

This afternoon I got the EGR out and cleaned it and also cleaned the boost sensor. Still getting the spannerlight although no EML so far. Still getting P0400-5A, any other suggestions for what I can do?

**djr69uk** · 23rd January 2011, 17:09

Originally Posted by Big Knox

yeah, not sure if the alternator is throwing up the fault. The spanner light then the EML light came on and when I put OP-COM on the car, the two faults came up together so I'm assuming perhaps the EGR is the cause of the lights and the alternator one might be from the past.

This afternoon I got the EGR out and cleaned it and also cleaned the boost sensor. Still getting the spannerlight although no EML so far. Still getting P0400-5A, any other suggestions for what I can do?

Did you take it completely apart and drill out as per the 'how2'? If not then you need to do this chap.

**Big Knox** · 23rd January 2011, 17:55

spoke to soon, EML back on. I have to admit I just cleaned the valve. I didn't have time to punch out the solenoid. I guess that's my next step. is there anything else this could be other than EGR or boost sensor? solenoid side of EGR didn't look too bad visually.