Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Proz]

Hi all .... i have been having problems with the P0420 code coming on all the time but after 2 new cats i just keep resetting the code .

Was coming back yesterday from visiting family and there was a really loud bang which after looking today turns out to be one of the rear springs giving up .....then further on the journey the mil light comes on again   .... assumed it would be the usual code but after reading it today its not ..... its P0170 fuel trim malfunction  :-/ :-/..... i have new springs coming tommorrow so as im working all over new year hopefully i can get the chance to change them at work  ....

So as for this new code before i start throwing money at this car or a box of matches where do i look to sort this code  

I have read Kevin Woods post on the issue  

Thanks

[Proz]

Here is the freeze frame data ..... hopefully it will help someone to see what is happening  

CALC LOAD   47.4%
COOLANT      167 (F)
ST FTRM        12.4%
LT FTRM         11.7%
ENGINE RPM   2716
SPEED           65 MPH

I had only been driving for maybe 10 mins on a cold start if it helps .

Thanks

[Proz]

Anyone ...... been doing a lot of looking on google for this code and lots of people seem to cure it by replacing the maf ..... should i try the same ?

[Kevin Wood]

It's possible it could be a MAF problem. There's a lot of fuel trim as you can see from the snapshot (short term plus long term).

Best way to diagnose would be to compare live data with a known good example. Maybe someone with an OBDII reader could take some readings of the MAF airflow data at, say, idle, 2000 RPM, 3000 RPM. Then you could do the same and compare.

The other possibilities would be an air leak in the induction system or poor fuel delivery (pump, filter clogged, pressure low, etc).

Kevin

[Proz]

It's possible it could be a MAF problem. There's a lot of fuel trim as you can see from the snapshot (short term plus long term).

Best way to diagnose would be to compare live data with a known good example. Maybe someone with an OBDII reader could take some readings of the MAF airflow data at, say, idle, 2000 RPM, 3000 RPM. Then you could do the same and compare.

The other possibilities would be an air leak in the induction system or poor fuel delivery (pump, filter clogged, pressure low, etc).

Kevin

I dont think my reader does live data .... only freeze frame  :-/