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View Full Version : Eliminating the Nasty P0300



1WkdEvo
10-29-2008, 01:17 PM
Looks like it may finally be resolved.

http://forums.evolutionm.net/showthread.php?t=377898

mrfred on Evom:

dan_l and I had been working on his P0300 error, and I finally have found the P0300 subroutines in the ECU code. More importantly, I found the periphery bit to disable the P0300 test. Both periphery2 bit4 and bit5 must be set to 0. bit5 is already set to zero on USDM cars, so it is only a simple matter of setting bit4 to zero.

The code for the P0300 test is pretty long, so besides banishing the P0300 code by disabling the P0300 test, the ECU will be a little bit more responsive to critical engine control (e.g. timing and fuel control), so I may disable the P0300 test on my own car even though my car has never thrown a P0300 error.

If you are using ECUFlash v1.35 or newer, the simplest way to set a periphery bit to zero is to copy the new periphery bit definitions to your ROM xml file, relaunch ECUFlash, and find Periphery2 bit4. The new periphery bit definitions can be found here:

http://forums.evolutionm.net/showthread.php?t=366879

Once you've got the definitions copied to your xml file, relaunch ECUFlash, select bit4, and hit the "minus" key. bit4 should change to 0. Save the file and upload it to your ROM.

If you are using an older version of ECUFlash, then copy the entry shown below to your XML file (save the xml file, and then relaunch ECUFlash):



When you open the Periphery2 entry, you should see: EFDF. Change it to EFCF by typing "0xEFCF" (without the quotes) and then pressing return. If you see something other than EFDF, post it up here, and I'll give you the correct value to enter.

NOTE: This is a complete rewrite of this post because I have confirmation from dan_l and house_of_senate that setting periphery2 bit4 to zero does disable the P0300 test.

Terenus
10-29-2008, 01:20 PM
Interesting, since I don't get the code it's basically like running less programs on Windows to free up resources.

Thanks for the link.

JOOTZ
10-29-2008, 01:26 PM
very good info

boostinbyyou
10-29-2008, 02:41 PM
HHMmmmmm.....

mnbvcxz
10-29-2008, 03:38 PM
THANK YOU!!!

hardcoreracing
10-31-2008, 01:51 PM
It appears to work for other ses codes as well. Prior to flashing the ecu last night, I was getting PO300 and also PO420. So far no ses light has come back on.

rino
10-31-2008, 03:08 PM
does this problem exist with IX's as well? I know the 03-04 evos have them.

I get it once every month on my 04, but after 2 days, it just goes away.

1WkdEvo
10-31-2008, 03:33 PM
Actually it is most common on the IX's as far as I know. I have had it for over a year

leaveit2bevo
10-31-2008, 07:28 PM
weird Ive never heard of it on the IX's just the 03-04

EvoJoe
10-31-2008, 08:02 PM
weird Ive never heard of it on the IX's just the 03-04


Same here, I've only heard of it on the 03-04's. I remember reading threads several years ago on Evom about guys having to have Mitsu buy their 03-04 Evo's back because they couldn't cure the P0300 issue. At first they were blaming the transmissions saying that they were creating some sort of bad harmonics that were causing the P0300 code. They were actually replacing transmissions under warranty, but they were still getting the code after going through all the trouble of doing the tranny swap. This new method of altering the ECU to get rid of the code seems like a real break through.

hardcoreracing
11-01-2008, 12:28 PM
The code only appeared after I got my cossie cams installed on my IX. I'm running more timing in the idle cells to smooth out the lope which could be another reason why I'm getting the code. I never did the 02 fix either.

I got the PO420 when I changed out my high flow cat to a rally cat. I had an 02 bung added to the rally cat when it was installed in the same location as the stock 02 sensor.

takeshi999
11-01-2008, 01:52 PM
hmm very interesting will have to try it...

Steveevo9
11-01-2008, 09:27 PM
The code only appeared after I got my cossie cams installed on my IX.Â* I'm running more timing in the idle cells to smooth out the lope which could be another reason why I'm getting the code.Â* I never did the 02 fix either.Â*

I got the PO420 when I changed out my high flow cat to a rally cat.Â* I had an 02 bung added to the rally cat when it was installed in the same location as the stock 02 sensor.


Have you had any luck with just tuning for a smoother idle with the PO300 & did the mech fix sort out your PO420?

hardcoreracing
11-02-2008, 03:24 PM
It's been three days now and still no code came back. I think it's gone for good. If it comes back, I'll post back up crying like a beotch how the ses light is blinding my eyes again.

To smooth out the idle on the cossies I am running 13 timing advance in the idle cells as well as raising idle to 1100 rpm. It's pretty smooth now, lope is not as noticeable at stop lights which is good for when a popo sneaks up on you. There's a thread that says that any timing over 7 at idle would trigger the PO300, but I tried lowering it to 7 and it still came on so I just went back to 13.

Steveevo9
11-02-2008, 08:55 PM
It's been three days now and still no code came back.Â* I think it's gone for good.Â* If it comes back, I'll post back up crying like a beotch how the ses light is blinding my eyes again.Â*

To smooth out the idle on the cossies I am running 13 timing advance in the idle cells as well as raising idle to 1100 rpm.Â* It's pretty smooth now, lope is not as noticeable at stop lights which is good for when a popo sneaks up on you.Â* There's a thread that says that any timing over 7 at idle would trigger the PO300, but I tried lowering it to 7 and it still came on so I just went back to 13.


Thanks for that mate, I'm in the process of adding some gear to my Evo 9, so I hope I don't run into any code problems.

hardcoreracing
11-10-2008, 10:02 AM
Well, my PO420 came back and tripped the ses light again. I used scantech and the PO300 is still gone though. I'm sure they will come up with a separate fix to get rid of the 420. Someday..

05-EVO-GSR
11-10-2008, 12:07 PM
What is P0420?

hardcoreracing
11-10-2008, 04:12 PM
P0420 Catalyst System Efficiency Below Threshold (Bank 1)

It only came on after my rally cat replaced my high flow cat.

leaveit2bevo
11-10-2008, 04:12 PM
P0420Â* Â*Catalyst System Efficiency Below Threshold (Bank 1)

It only came on after my rally cat replaced my high flow cat.


ecuflash has a fix for this no worries you just need the newest tephra version