Brz goes into limp mode without any CEL - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

GrandSport · 01-27-2025, 12:29 PM

Really bizarre.

ONE TIME, I got a code, u0155- loss of comm with instrument cluster. Other than that, limp mode many times, no CEL.

It just cuts a ton of power to where it’s barely able to hold 50mph.

Dedicated race car.

The only pattern I can see is- it’s most common after I run a few sessions, then break for lunch, then drive again. It’s after the long break that it does it. Almost never in the first 2 sessions.

anyone have any ideas?

RT-BRZ · 01-27-2025, 01:26 PM

Quote:

Originally Posted by GrandSport

Really bizarre.

ONE TIME, I got a code, u0155- loss of comm with instrument cluster. Other than that, limp mode many times, no CEL.

It just cuts a ton of power to where it’s barely able to hold 50mph.

Dedicated race car.

The only pattern I can see is- it’s most common after I run a few sessions, then break for lunch, then drive again. It’s after the long break that it does it. Almost never in the first 2 sessions.

anyone have any ideas?

Pinched/frayed/exposed wire somewhere?

DarkPira7e · 01-27-2025, 01:32 PM

How are you pulling this code? Are you using a code reader to clear the CEL or actually digging into it with ECUtek or whatever your tuning platform is?

GrandSport · 01-27-2025, 02:55 PM

Quote:

Originally Posted by DarkPira7e

How are you pulling this code? Are you using a code reader to clear the CEL or actually digging into it with ECUtek or whatever your tuning platform is?

just a code reader.

GrandSport · 01-27-2025, 02:56 PM

Quote:

Originally Posted by RT-BRZ

Pinched/frayed/exposed wire somewhere?

man, there's a lot of wires! but we were looking

RT-BRZ · 01-27-2025, 03:10 PM

Quote:

Originally Posted by GrandSport

man, there's a lot of wires! but we were looking

Yeah, I knew that would be the unfortunate case when I said it. You're racing it so you never know what might be rubbing or lose or something silly because of the conditions.

blsfrs · 01-28-2025, 08:54 AM

Does it clear up on it's own? Or after you clear the code? You really need a datalog while it's misbehaving.

GrandSport · 01-28-2025, 05:45 PM

I shut it off, start it back. Sometimes it get better. sometimes it doesn't.

NoHaveMSG · 01-28-2025, 10:20 PM

That is going to be a tough one. Does it only rev to a specific RPM in limp mode? There is a chart in the online manual with the fail safe condition associated with certain DCT’s, even though you aren’t getting any may help narrow the search.

GrandSport · 02-11-2025, 05:30 PM

This was definitively determined to be the AIM dash.

01-27-2025, 12:29 PM	#1
GrandSport Senior Member Join Date: Sep 2018 Drives: 13 Viper; 14 BRZ; 90 Miata; 18 AMG Location: TX Posts: 354 Thanks: 76 Thanked 214 Times in 119 Posts Mentioned: 5 Post(s) Tagged: 0 Thread(s)	Brz goes into limp mode without any CEL Really bizarre. ONE TIME, I got a code, u0155- loss of comm with instrument cluster. Other than that, limp mode many times, no CEL. It just cuts a ton of power to where it’s barely able to hold 50mph. Dedicated race car. The only pattern I can see is- it’s most common after I run a few sessions, then break for lunch, then drive again. It’s after the long break that it does it. Almost never in the first 2 sessions. anyone have any ideas? __________________ 2014 BRZ: WRL Build (GP2) Gutted, caged, coilovers, AP enduro, etc- 2013 Viper GTS : Tractive Coilovers, ACR sway bars, aero, carbon, exhaust, etc. 1992 NA Spec Miata: 1.6 + 1999 NB Spec Miata: 1.8 w/ all the goodies. 2022 CT5 Blackwing: Stock. 2024 GMC Sierra AT4 2500HD: knock knock knock knock knock... (toy hauler)

01-27-2025, 01:32 PM	#3
DarkPira7e Rust bucket enthusiast Join Date: Feb 2017 Drives: 2013 Turbo Firestorm FRS Location: Vermont Posts: 3,971 Thanks: 3,238 Thanked 4,129 Times in 2,065 Posts Mentioned: 31 Post(s) Tagged: 0 Thread(s)	How are you pulling this code? Are you using a code reader to clear the CEL or actually digging into it with ECUtek or whatever your tuning platform is? __________________ Turbo FR-S Build - Build Thread JDL EL Recirc manifold, Boostlab BL58x Turbo w/ T51R, 17x9 ARC-8, IAG block

01-28-2025, 05:45 PM	#8
GrandSport Senior Member Join Date: Sep 2018 Drives: 13 Viper; 14 BRZ; 90 Miata; 18 AMG Location: TX Posts: 354 Thanks: 76 Thanked 214 Times in 119 Posts Mentioned: 5 Post(s) Tagged: 0 Thread(s)	I shut it off, start it back. Sometimes it get better. sometimes it doesn't. __________________ 2014 BRZ: WRL Build (GP2) Gutted, caged, coilovers, AP enduro, etc- 2013 Viper GTS : Tractive Coilovers, ACR sway bars, aero, carbon, exhaust, etc. 1992 NA Spec Miata: 1.6 + 1999 NB Spec Miata: 1.8 w/ all the goodies. 2022 CT5 Blackwing: Stock. 2024 GMC Sierra AT4 2500HD: knock knock knock knock knock... (toy hauler)

02-11-2025, 05:30 PM	#10
GrandSport Senior Member Join Date: Sep 2018 Drives: 13 Viper; 14 BRZ; 90 Miata; 18 AMG Location: TX Posts: 354 Thanks: 76 Thanked 214 Times in 119 Posts Mentioned: 5 Post(s) Tagged: 0 Thread(s)	This was definitively determined to be the AIM dash. __________________ 2014 BRZ: WRL Build (GP2) Gutted, caged, coilovers, AP enduro, etc- 2013 Viper GTS : Tractive Coilovers, ACR sway bars, aero, carbon, exhaust, etc. 1992 NA Spec Miata: 1.6 + 1999 NB Spec Miata: 1.8 w/ all the goodies. 2022 CT5 Blackwing: Stock. 2024 GMC Sierra AT4 2500HD: knock knock knock knock knock... (toy hauler)

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

01-28-2025, 08:54 AM	#7
blsfrs Senior Member Join Date: Dec 2018 Drives: 2013 frs base Location: central Virginia Posts: 1,324 Thanks: 2,296 Thanked 1,311 Times in 618 Posts Mentioned: 13 Post(s) Tagged: 0 Thread(s)	Does it clear up on it's own? Or after you clear the code? You really need a datalog while it's misbehaving.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
How to Fix Limp Mode?	MidnightFumes	Issues \| Warranty \| Recalls / TSB	7	01-20-2021 05:18 PM
Limp mode at 2K rpm NEED HELP!!	Arthur_frs	Engine, Exhaust, Transmission	5	04-13-2020 10:22 PM
Limp mode	GTBOY	Issues \| Warranty \| Recalls / TSB	4	06-07-2018 12:58 PM
Valet mode / limp mode?	radroach	Software Tuning	1	09-18-2017 11:34 AM
Car in Limp mode... No CEL	Sportsguy83	Issues \| Warranty \| Recalls / TSB	60	08-20-2014 03:35 AM

User Name		Remember Me?
Password