[Davyhay]

I have a JB4 G5 ISO and on two occasions, I noticed that it switched from Map 5 to Map 4 on its own. Has anyone else experienced this? Any idea why this happens?

[WedgePerformance]

Yes, happened to me a few times as I was playing. I didn't say anything to Terry, but he sent me a new firmware. Jump over to 54 tech and get the latest firmware. I'm sure if it happend to you and me it's a known issue. I'll shoot him an email to see if he's aware. He's out of town this weekend so more than likely he won't get back to you until tomorrow.

[Myrder]

It will put you into Map 4 if it senses over-boost or other detrimental conditions on your car. Depending on your firmware one version had throttle issues that threw people into map 4 (me included) the newest firmwares solve this.

[Davyhay]

Thanks for the responses, guys. The last time it did it, the car flashed service engine soon for a couple seconds and then went to map 4.

[chili36]

The JB4 has two active safety systems that will trigger SES light flashes. The first is the over-boost safety. If boost exceeds the value you've set under user adjustment the SES light will flash two times and the JB4 will switch itself to map 4 until you restart the car. The default setting is 18psi. Common causes for this are setting the value too low for the map/intended usage, improperly configured or defective wastegates, or JB4 setting problems.

The second is the run-lean safety system. If your air/fuel ratio (either bank) runs leaner than 14:1 over 4500rpm for more than a second the SES light will flash four times and the JB4 will again switch itself to map 4 until you restart the car. Common causes are maxed out fuel trims (see E85 notes above), low fuel pressure due to a failing fuel pump, or o2 sensor faults. Note any o2 sensor fault must be corrected for the tuning to operate properly.

[WhiteFury]

Mine only switches in map#2 in 3rd gear or higher at wot. I can feel the car sputter or like a rev limiter and it switches to map #4. I have the failsafe at 18psi.

Why am I hitting 18+ psi in map2? Map5 is great.

I can see map5 reduce the boost once it reaches 18 and brings it to 16-17.

I have evolution racewerks charge pipe.

[Jhe]

If I'm not mistaken, it has to do with what mods your car has, and I'm pretty sure what gas you are running has something to do with it. As another member mentioned, its a failsafe if something isn't right.... Map 4 is the default stock map. I did data logs and emailed them to BMS, made a few tweeks (per their recommendation) and haven't had a problem since. The one other thing I did was remove the firmware, and reloaded it.... I forget which page it is, but there is a drop down menu for the different versions of firmware.... make sure you're loading the correct version for your car.
Good Luck.

[mike@x-ph.com]

It goes to map 4 as a fail safe (its either you are overboosting or you are running very lean).
Check if the map you running is the recommended one for your mods.
If you are running the BMS flash let terry know so he can adjust fuel scalar and fuel tables.

[Osirisman]

Installed jb4 couple days ago with dci.
I've noticed this as well, that it will switch to map 4 on its own from map 1 or map 2.
I broke traction checked map selection and it was on 4.
No cel lights.
Car is a 2011 335is.