Do you have anyone reporting a P0401 code on an Evo 8?

 

Not yet. I had people reporting a P1400, but I got that one fixed. After finding similar fault check tables in the Evo 9 ROM, I am surprised that Evo 9s are not throwing a P1400. I will be posting more info about these tables in the Evo 9 soon.

If you want to add periphery2, copy my "Periphery4" entry, and change the address to FCA (and change the name to Periphery2).

 

I've actually gotten that code twice since installing the JDM sensor on my '03 with ROM 94170015, so about once a week. I didnt report it since I thought it was a known issue.

Mike

 

Good info. You updated all the tables in the instructions, correct? Just want to be sure.

 

Yes I did. I'll send you a copy of my current ROM if need be as well, just PM me.

Mike

 

Here's some more P0401 code info for the Evo IX with the 88590015 ECU...

So as I said in my previous post (here... https://www.evolutionm.net/forums/sh...&postcount=314) I threw a P0401 code on the way to the track last week. This had been on a long stretch of road, cruising at a steady ~60mph. After cruising for quite a while, when I let off the gas, the SES light came on.

Well guess what... almost exactly 1 week later, SAME stretch of road, same long period of traveling at ~60mph... when I let off the gas pedal... ding! SES light. Yup, it's the P0401 code.

I know this is related to the JDM map sensor we have installed. But I'm not sure what it is about driving 60mph for a while, then letting off the gas that causes the code. Is the ECU testing the MAP sensor under this condition?

Anyway, thought I'd add this info to maybe help "mrfred" figure out what might be causing this.

Thanks!

 

Thanks. I've got a copy of an Evo IX service manual arriving today. I'm hoping that the diagnostics section will give me a better idea of whether the EGR check works any differently than the Evo VIII.

 

Got the EGR related SES on my IX this weekend. Good luck on tracking down the solution Fred.

 

How much time/miles elapsed while you were driving @ ~60 mph? I want to try and replicate what you did and see if I get an SES light.

 

I got into my Evo 9 FSM last night. Here are the conditions needed to trigger an EGR performance check:

• At least 20 seconds have passed since the last monitor was completed.
• Engine coolant temperature is higher than 76° C (169° F).
• Engine speed is at between 1,000 and 2,000 r/min.
• Intake air temperature is higher than - 10° C (14° F)
• Barometric pressure is higher than 76 kPa (22.4 in. Hg).
• Vehicle speed is 1.5 km/h (1.0 mph) or more.
• At least 90 seconds have passed since manifold absolute pressure sensor output voltage fluctuated 1.5 volts or more.
• The throttle valve is closed.

Once I track down the RAM address for coolant temperature, RPM, intake temperature, TPS, and vehicle speed, it should be pretty easy to pinpoint the routine using these data.

 

It was ~14.9 miles (according to Google maps)... so if I was truly averaging 60 mph then it'd be about 15 minutes, but I probably wasn't averaging exactly 60mph, so it was maybe a little more than 15 minutes. But it was pretty close to 15 solid minutes at ~60 mph.

I suppose the other factor to consider is that this was almost exactly 1 week after the first time I got an SES. But I found it interesting that traveling the exact same road at 60 mph would again cause an SES.

I can also note, that the first time I got an SES, I didn't go quite as far on the road. So the first time I got an SES light it was maybe 10 minutes instead of 15 at 60 mph.

 

are we sure the MAP sensor is only used to check EGR condition?

I just installed my sensor yesterday and after driving about 20 miles it threw the P0401

conditions were pretty similar to what's described in the evo9 FSM drive cycle test
(for those in the bay area, was driving west on 237 in traffic)
lots of letting off the throttle and such

after getting home and fiddling with the car, it felt pretty different
oddly enough smoother, yet less "jumpy" with the throttle
decelerating in 1-3 gear was less jerky and it felt like the engine wouldn't bog as easily

think this would warrant some more testing? test the egr valve/solenoid with the stock ROM & stock MAP vs these revised ROMs with the JDM MAP sensor?


ps. 88590015 rom

 

There are quite a few references to the MAP sensor in the ROM. Its possible that it could play some role besides verifying EGR performance. I've been working through the ROM as much as I can to try to understand all the things the MAP sensor affects.

 

anyone have a stock map sensor + harness for sale?

 

Any new developments on the SES solution Mrfred?