Help/Advice with Yaris Cross PCA/LTA Malfunction 'C05261C'

[MrEthical12]

Hi there folks, hope you’re all doing well.

I had a minor collision a few months ago with my Yaris Cross on the passenger side, and I’ve since had it repaired. The damage was mainly to the bumper, headlight, and the wishbone on the passenger side. All of those parts have been replaced, and the car’s been aligned. However, since the repairs, I’ve been dealing with a Pre-collision malfunction, LTA malfunction, and a brake hold malfunction.

I’ve got access to Techstream V18 and managed to pull up some codes related to the Brake System / Front Radar Sensors. The codes I’m getting are U012987 and C05261C. One thing that stood out to me is an issue with the steering angle sensor. The data list shows 0 degrees for the steering angle point, but the brake system data shows a steering angle of 33 degrees. I’ve tried clearing the DTC codes and resetting the memory before performing a zero-point calibration, but every time I drive above 20 km/h, the errors reappear and stay until I clear them again.

I’ve gone through and checked every fuse in the vehicle, and everything seems to be in order. The wiring harnesses look fine as well—no visible signs of damage. Since I only replaced the wishbone on the side of the impact and not the track rod end or hub, I’m wondering if that might be part of the issue. But no matter what I do, the error codes keep coming back.

I’m attaching some images from Techstream to give a better picture of what’s going on. Any help or advice would be really appreciated—thanks in advance!

[MrEthical12]

Update – Issue Resolved (LTA/Lane Assist/Brake Hold Malfunction) 

Hi all,

Just wanted to provide an update on the issue I was having with the LTA, Lane Assist, and Brake Hold malfunctions. After exploring different avenues, I managed to resolve the problem myself.

First, I took the vehicle to the dealership for a diagnostic check, which set me back over £200+. They identified the problem as being related to the C05261C code, meaning the steering angle sensor was faulty. According to them, I would need to replace the sensor to resolve the issue. I requested a diagnostics report from the master technician at Toyota, and they provided me with a document outlining exactly what needed to be done. The total charge for the replacement sensor and labor? A hefty £880+ including VAT.

After reading through their proposal, I decided to take matters into my own hands. I sourced a used steering angle sensor from an online vendor at a much lower cost. I then removed the steering wheel and replaced the faulty angle sensor myself. During the process, I made sure the new (used) sensor aligned back to 0 degrees. I used Techstream V18 to monitor the live data during the replacement, ensuring everything was in sync. Interestingly, the used sensor I purchased initially showed a value of over 360 degrees, which was quite alarming.

Once the sensor was back to 0 degrees, I disconnected the Battery, reassembled the steering wheel and airbag system, then reconnected the Battery. I cleared the DTCs (including the airbag codes) and recalibrated the steering angle sensor. And just like that—problem solved. All codes were cleared, and the malfunctions were gone.

 

Top tip:

If you're replacing the steering angle sensor module, you’ll likely need to perform an ECU security key reprogramming. This is a tricky part because you can’t do it without access to the dealership’s platform that allows for ECU read/write. Without this, you’ll keep seeing the DTCs even after replacing the sensor, as the ECU in the sensor module must match the vehicle's ECU.

 

Main tool I used for diagnostics:

- TopDon RLINK J2534 

- VXdiag VCX SE

In the end, the DIY approach saved me a significant amount of money and time, and I learned a lot along the way. Hopefully, this update helps anyone else facing a similar issue!