Yes this is caused by an over boost condition. You must tune the airflow check and torque limiter maps in your ecu to resolve this problem.

 

P1235 Overboost from MBC

P0420 Catalyst System Efficiency Below THreshold (Pending)

P0137 O2 Sensor Circuit Low Voltage (Pending)


Looks like after testing some partial throttle highway runs on the new GT30 turbo I'm starting to trigger some new codes... bah. I already upped my airflow check and torque limiter maps but it looks like I need to increase the partial throttle ones as well.

I also went into limp mode on the Dyno when the driver went to WOT at 2k... about 1 second later it threw the SES light. We just reset the battery to get moving as my OBD2 cable wasn't handy but I'm not sure what would fix a lack of airflow check in the limits tables. For now I'm just avoiding full throttle under 3k if I can help it.

Edit: GST confirmed that if the turbo is laggier by 500-1000 rpms I can shift the tables downward so that the 2000 RPM numbers aren't as high. I bumped the other numbers higher yet under partial throttle boost and will verify with the logger by doing some partial throttle boost pulls at various boost levels to verify AFR's are safe and that there is no knock.

Seems odd that my P0420 codes are starting to surface again as well as I haven't touched the rear half the exhaust in a while.

 

i never hit limp mode before so im guessing this is it. but what weird is i can't boost above 5psi or so and i hear no turbo spool or anything...then when i go to give it a little more gas all powers gets taking away and the check engine light goes on. This started happening after i replaced my UICP, LICP, Intake and swapped valve covers. I installed all the parts myself the first time and no problem, i took them off (to send them to get powerder coated at JNZ) and put my stock piping on and no problem, no i got put it back on and this happens. I checked everything last night and couldn't see the problem. Im gonna check again tonight when i get off work but if anyone has an idea of what this could be let me know. Also my car does not read the outside temperature...it just says ---. I have no clue if this has any connection to the problem or why its doing that.

 

Verify that there are no boost leaks and find a way to read the specific OBD2 codes. Usually the Limp mode where you just see a SES come on suddenly is the Airflow Limits map, setting the target load percents too high or too low will trigger the no more than 5 psi boost limp mode. It mainly restricts TPS down to 30-40% from what I can tell.

It seems the Torque limits Limp mode will trigger that yellow skid mark symbol on your dash then severely hamper power depending on what you were doing at the time. I'm currently fighting some stutter box limp modes where my limits are likely too high to allow that low airflow combination but I need them to allow over 28 psi on the GT30 at higher rpm's.

 

the yellow skid screen came up and said service required or something along the lines of that if i recall correctly. It just sucks cause tomorrow im supposed to bring my car to Ivey to get my Red, Aqaumist and other parts installed. Everyone said that it should be safe to drive down to him and just stay out of boost. He's only about 15-20 miles away from me. When i get off work today im gonna check everything over and hopefully figure it out.

 

that is exactly what happened to me, and i was using the Turbosmart Dualport which only halfway VTA.