16-07-2015, 12:27 PM
Here is small case study about dreadful P0402 error.
As I was pulling to the A1 went into limp mode. After 2 km stopped at the gas station and plugged in my
bluetooth OBDII android. Greeted with P0402 . Cleared the error and continued my journey. After another 2km
limp mode again. Same error. After 2 more stops and clearing the error find out that if I keep revs above 3000 rpm
I can continue without limp mode. If my revs fall to 2800 rpm i got limp mode. OK so I kept revs above 3k and continued
to the destination and back next day. Total 1000 km with revs above 3000 rpm.
Here is the OBDII error code:
From OBDII error it is not clear if the ERG or MAF is causing the P0402. Dirty MAF can measure wrong air quantity
and trow P0402.
Connected the car to the Lexia and took a closer look at the error P0402 :
Looking at the EGR valve position 89% and revs 2377 rpm it was no brainier. EGR was stuck open and it was
passing more air into the engine than MAF sensor was picking up.
Time to take EGR apart.
This is electrical EGR. Consists of 2 parts. Lower mechanical part where the valve is situated and upper electrical motor part
witch is used to open and close regulating valve.
Just undo 3 bolts and 2 parts are separated. When I moved lower part of the EGR it was moving freely.
When I moved upper electrical part there was some resistance. Like it was "jumping" in one place.
So I opened electrical part:
I have found the problem. Bearing has lost it's lubricant due to carbon residue going to it. Without the proper lubricant bearing
balls were "eaten" at one point creating "jump". So the only solution is to order another EGR because it is impossible to change
that bearing. Mechanical part was ok and it was used to "blank" the EGR :
With 2 wires connected to valve small shaft , valve is pulled up closing the gap and EGR is blocked properly.
I have ordered one from Aliexpress 90$ with shipping , 1 year warranty. Prices at the dealer are nightmare
After 3 weeks of driving with blanked EGR and limp mode fitted new EGR and cleared the error P0402 everything is OK.
Sorry for the long post. Hope it helps someone.
Best regards,
brajomobil
As I was pulling to the A1 went into limp mode. After 2 km stopped at the gas station and plugged in my
bluetooth OBDII android. Greeted with P0402 . Cleared the error and continued my journey. After another 2km
limp mode again. Same error. After 2 more stops and clearing the error find out that if I keep revs above 3000 rpm
I can continue without limp mode. If my revs fall to 2800 rpm i got limp mode. OK so I kept revs above 3k and continued
to the destination and back next day. Total 1000 km with revs above 3000 rpm.
Here is the OBDII error code:
From OBDII error it is not clear if the ERG or MAF is causing the P0402. Dirty MAF can measure wrong air quantity
and trow P0402.
Connected the car to the Lexia and took a closer look at the error P0402 :
Looking at the EGR valve position 89% and revs 2377 rpm it was no brainier. EGR was stuck open and it was
passing more air into the engine than MAF sensor was picking up.
Time to take EGR apart.
This is electrical EGR. Consists of 2 parts. Lower mechanical part where the valve is situated and upper electrical motor part
witch is used to open and close regulating valve.
Just undo 3 bolts and 2 parts are separated. When I moved lower part of the EGR it was moving freely.
When I moved upper electrical part there was some resistance. Like it was "jumping" in one place.
So I opened electrical part:
I have found the problem. Bearing has lost it's lubricant due to carbon residue going to it. Without the proper lubricant bearing
balls were "eaten" at one point creating "jump". So the only solution is to order another EGR because it is impossible to change
that bearing. Mechanical part was ok and it was used to "blank" the EGR :
With 2 wires connected to valve small shaft , valve is pulled up closing the gap and EGR is blocked properly.
I have ordered one from Aliexpress 90$ with shipping , 1 year warranty. Prices at the dealer are nightmare
After 3 weeks of driving with blanked EGR and limp mode fitted new EGR and cleared the error P0402 everything is OK.
Sorry for the long post. Hope it helps someone.
Best regards,
brajomobil
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