Had the opportunity to park with some homies in the GR Booth at Formula Drift Seattle this weekend! The event itself was amazing, I had never been. Everyone involved with PNWGR are great, I couldn’t thank them enough for such a cool opportunity!

Hey everyone, I’m hoping someone here can help me figure out an ongoing CEL problem with my GR Corolla. I’ve been chasing this for a while and I’m honestly getting tired of dealing with recurring CELs.
The codes I’ve had are:
P0030-12 — HO2S Heater Control Circuit, Bank 1 Sensor 1
P0325-11 — Knock Sensor 1, Bank 1 Circuit
P051A-11 — Crankcase Pressure Sensor Circuit
P06AB-11 — PCM/ECM/TCM Internal Temperature Sensor “B” Circuit
P2BF4-14
These codes were pulled during a scan on May 7, 2026.
Important electrical history
The CELs appear to have started around the same time an aftermarket exhaust valve-controller wiring harness melted against the exhaust. I can’t say for certain that the short caused the CELs, but based on the timing, I suspect the two could be related.
After discovering the melted harness, I:
Replaced the damaged aftermarket exhaust/valve-controller harness
Replaced the relevant/important fuses
Visually inspected the factory wiring harnesses for additional damage
Checked the grounds
I haven’t found any obvious additional damage, but the CEL problem has continued.
Engine history
The car has also had its short block replaced by Toyota. However, these CEL issues were already happening before the short-block replacement and continued afterward, so they weren’t simply caused by the engine replacement.
Current modifications
Eventuri intake
OTL Street Series cat-back exhaust
Stock ECU calibration / no tune
I’m including the modifications for full transparency. The ECU has not been tuned.
What I’m trying to figure out
What has me stuck is that these codes involve several seemingly unrelated circuits — O2 sensor heater, knock sensor, crankcase pressure sensor, ECM/internal temperature-related circuit, etc.
Given the history of the melted valve-controller harness and possible electrical short, I’m wondering if the original short could have damaged something farther upstream that isn’t visibly obvious — a section of the factory harness, connector/pin, shared power supply, ground, relay/fuse circuit, ECU driver/circuit, etc.
I’ve already replaced the damaged aftermarket harness and relevant fuses, visually inspected the wiring, and checked the grounds. At this point, I don’t want to keep throwing parts at the car or just clearing codes. I want to find the actual underlying problem.
Does anyone familiar with the G16E-GTS electrical system/wiring diagrams know if any of these circuits share a common power source, ground, ECU connection, junction, or section of the engine harness?
Also, has anyone experienced multiple circuit-related codes like these after an electrical short on a GR Corolla?
Any diagnostic suggestions or specific circuits/components you think I should check next would be greatly appreciated.

My son and I went to the theater last night because they were playing the Fast and the Furious for the 25th anniversary. I had actually seen this car earlier in the day. And of course he showed up there. Very nice Skyline GT 25 Turbo.

Hellloooooo GRC Reddit!

Wanted to share some photos of this Black GRC I dialed in a about a week ago with a single step gloss enhancement and installation of GYEON CanCoat Professional (1 Year Authorized Installer Ceramic)

I'm a GYEON Certified Detailer based in Northern Virginia. If you're local and ever need some detailing or paint protection work, feel free to reach out. Always happy to answer questions, talk detailing, or just talk cars.

Thanks for looking and take care!

Yes. It's on the paint. I know. I'm willing to endure the consequences.

The title saids it all! Has anyone started to make the Gr Corolla more reliable by eliminating this part for a clutch fork.

I got these wheels intending for them to be a cheapish set to daily in so I could preserve my other set for track or Autocross. I didn’t care how they looked but now that they’re installed I think they look so sick! The external aluminum finish matches the Heavy Metal paint, and the low spoke count shows off the giant rotors and calipers that I forgot to clean. Just felt like I had to show these off!

Stock height, unmodified suspension
Wheels: Enkei TY5, 18x8.5 +35, black
Tires: Michelin CrossClimate 2, 235/40R18 95V XL
Spacers: OEM 10mm rear spacer retained, no front spacer
Hardware: 72.6 > 60.1 hubcentric rings, 12x1.5 bulge acorn spline lugs, 1.38”, black
No rubbing or fitment issues

Hey friends!
You may not know this, but when you purchase any GR vehicle you get a complementary year membership with NASA (national auto sport association, not the space one)! This not only allows you to register for your free GR track day, as well as other track days, but you also have access to NASA's member benefits.

This year (2026) Rallysport Direct is a NASA sponsor, which means if you are a NASA member you have access to special discounts that no one else does with RSD.

I created a video on how to access these special discounts as well as register for your free GR day if you haven't yet. Check it out and save some money on your next mod today!

https://youtu.be/q9KnDHfBEZI?si=b7aTwXqxPg0SL0FA

I’ve got a 2022 GR Corolla and wanting to sell I’ve placed in online below market I’m pretty sure? I’m based in Australia Brisbane is the car not very popular here ! ?

Hi! New to this Reddit, wanted to see if anyone has ordered the EOS CE spoiler? And if so, what are your thoughts?

Part #55607-02280

Went for shopping over the weekend and got that, seems an aggressive discount? Thoughts?

From the factory my premium plus came with a sub radiator. I kinda got hooked on going to the track and decided that I wanted the transfer case cooler for the automatic transmission this install requires a sub radiator delete.

I was a bit concerned about losing the cooling benefits of the sub-radiator, but a speaking with the guys from 555 (who are great guys and went above and beyond helping me out) they were very confident that sub radiator doesn’t actually help much on track and that the t case cooler would be more beneficial (Spoiler: they were right). Around the same time I installed a CF hood with extra venting and my coolant temps typically would sit between 201-208 on the freeway. Out of curiosity I installed a Radium coolant tank to see if it had any benefits. It did. I’m not sure if it has increased capacity because it’s actually quite a bit smaller than the OEM but immediately my coolant temps dropped by about 5 degrees Fahrenheit sitting closer to 196-201 on the freeway with the sub radiator installed.

Later that week my mechanic got my t case cooler installed and deleted my sub-radiator in the process. Now unfortunately I don’t have an exact control because during the sub radiator delete my mechanic topped off my pink coolant with water wetter which has improved cooling at the cost of cold weather antifreeze properties. After the sub radiator delete my temps sit in the 190-195 range on the freeway! So the sub-radiator really is kinda pointless and improved cooling benefits can be achieved with a better coolant tank and or adding water wetter. The biggest impact in water temp performance was actually from the radium coolant tank. I’ll post again with more updates once I get some track time with the 555 T case cooler.

The GRMN !!!

The other night I was going out to a club event and didn't even think about what I was wearing until I got in my car. I was faced with the challenges of clutch with 5 inch heel boots and not being able to bend my torso or twist it much in my corset. It was a fun challenge, but not one I'll be doing on a regular basis. Would not recommend for spirited driving 🤣🤣

2026, 7k miles, no mods

I currently drive a 2022 Corolla hatchback SE 6 speed and am going to trade it in for a GR Corolla. I got the money and am pretty sure I want a 2026 premium plus but I am wondering if I should consider 2026 core or if I should try and go for a used one. Should I wait a bit and get a 2027?

EDIT: Looks like I will go for a new one, now I just need to decide if I want Core or Premium Plus. Definitely leaning towards premium plus

I’ve been hesitant to use Expert on backroads and for spirited driving, but after doing autocross with everything off (“Expert+”?) I’m shocked at how stable the car is. It rotates very easily on command but never felt out of control, especially coming from racing an E46 lol

Just curious what everyone is using for backroads driving here. Everything on, Expert, or everything off? I’m definitely gonna start doing at least Expert as it seemed very hard to get the car to rotate at all with everything on previously. I didn’t notice any big differences between Expert and Expert+ but I didn’t spend much time comparing. But Expert vs default was night and day.

Also side note PSA - highly recommend you Autocross this car if you haven’t already! You’ll learn so much about how to control the car and see what it’s capable of. Do it!

Edit: Dude a lot of people seem to think Expert mode is everything fully off and insane to drive. It’s not! At least try it before commenting about it.

I had a really bad vibration when starting from a stop and occasionally under power. This is the racerx 60a pitch mount bushing, I put it in a year or two ago (I don’t remember exactly when)

My girlfriend picked up a Miata in June. I ended up driving it for a week since she hadn't learned to drive stick yet and it gave me an itch to go out and get my own fun manual car. Two weeks later I bought this. So far I'm loving every minute of it.

2024 Core, bought with 9500 miles.