C1231: Toyota skid control (ABS/VSC) fault, tied to the steering angle sensor input
Toyota ABS and VSC code C1231
Severity: Inspect soon
Owners with C1231 report the VSC and traction lights on, and Toyota bulletins show it can come with a warning light from repeated ABS and traction events; stability and anti-lock help may be off.
It gets more serious if:
- Stop: Stop and have it checked if the red BRAKE light comes on, the vehicle drifts or stops suddenly, or the pedal feels different.
C1231 in short
On Toyota vehicles, C1231 is a skid control code that a dealer tied to the steering angle sensor input. It lights the VSC and traction lights, and Toyota bulletins for the Sequoia and Camry fix some cases with a computer logic change. Have the brakes and stability system inspected soon.
Owners of 2003 Sequoias report C1231 with C1203, C1223 and C1241, the VSC and TRAC lights on, and in some cases the vehicle drifting or stopping suddenly. One dealer diagnosed a steering angle sensor for ABS.
Toyota bulletins on NHTSA name C1231 for a 2003 Sequoia (skid control computer logic) and 2009-2011 Camry (ABS ECU logic). Only the summaries were read.
A logic change means that on some vehicles the code can be a software issue, not a failed part.
Pick your make
C1231 is a manufacturer-specific code: its meaning depends on who built the car.
Other makes: meaning not verified. Check with a scan tool that reads manufacturer definitions.
Most likely causes
Cause 1: Skid control or ABS computer logic that needs an update
Supported by vehicle data- Why it ranks here
- Toyota bulletins name C1231 and say the skid control or ABS computer logic was modified for the Sequoia and Camry. Only summaries were read, so the label is bulletin-backed but unverified for your VIN.
- What would change this
- Rises if a dealer finds your VIN covered. Falls if the software is current.
Cause 2: Steering angle sensor or its calibration
Supported by vehicle data- Why it ranks here
- A Sequoia dealer diagnosed a steering angle sensor for ABS with C1231. One report, so it ranks below the bulletins.
- What would change this
- Rises if the sensor reading does not follow the wheel on a scan tool. Falls if it tracks correctly.
Cause 3: Skid control computer hardware fault
Possible — needs testing- Why it ranks here
- Several Sequoia owners were told the skid control computer needed replacement, with other ABS codes stored.
- What would change this
- Rises if C1203, C1223 and C1241 are stored too. Falls if C1231 is alone.
What to test first
Start at step 1. Each result tells you what it means and where to go next.
Step 1: Read all ABS and stability codes and watch the steering angle reading against the actual wheel position.
IfC1231 is alone and the steering angle reading is wrong
It meansSuspect the sensor or its calibration.
IfC1203, C1223 and C1241 are stored too
It meansSuspect the skid control computer.
IfThe readings look normal
It meansAsk a dealer about a computer update.
Points to: Skid control or ABS computer logic that needs an update
Symptoms
- VSC and TRAC lights on
- ABS warning light on
- Parking brake light going on and off
- Vehicle drifts or stops suddenly Gets more serious: stop and have it checked.
How to fix
This is a safety-critical system, so we explain the code but don't give repair steps. Have it inspected by a qualified technician.
Parts and cost context
- Brake system control module (ABS module):Owners report skid control computer quotes in the thousands; ask about software updates first and get a quote.
Labor varies by vehicle and shop; get a quote before you approve a repair.
Compare used part prices on PartPriceGuideOn your vehicle
ToyotaYour car
2001–2003 · Sequoia
Supported by vehicle dataSequoia owners report C1231 with C1203, C1223 and C1241 and VSC lights. Toyota bulletin 00303 covers a logic change. Only the NHTSA summary was read.
2009–2011 · Camry
Supported by vehicle dataToyota TSB-0086-13 (also filed as T-SB-0086-13) covers a repeated ABS and TRAC light with C1231 on Bosch ABS/VSC, fixed by an ABS ECU logic change. The summary text was read; whether it is current is not verified.
00303Status unverified
VSC light on with C1231
2003sequoia · NHTSA 10005246
A skid control computer logic modification was made to prevent the condition. Summary only.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
TSB-0086-13Status unverified
Warning light on with repeated ABS and TRAC and C1231
2009–2011camry · NHTSA 10053729
The ABS ECU logic was modified to address the condition. Summary only.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
Related codes
C1231 questions
Can C1231 be fixed without replacing parts?
Sometimes. Toyota bulletins for the Sequoia and Camry describe a computer logic change for C1231, so ask a dealer before agreeing to a part.
Sources and review
- Toyota 00303: VSC light on with C1231 in the skid control computer memory (2003 Sequoia)
- Toyota TSB-0086-13: warning light on from repeated ABS and TRAC with C1231 (2009-2011 Camry)
- NHTSA complaint ODI 10171069: 2003 Toyota Sequoia C1203 and C1231
- NHTSA complaint ODI 10294053: 2003 Toyota Sequoia SR5 C1231
- NHTSA complaint ODI 10185717: 2003 Toyota Sequoia C1241, C1231, C1223, C1203
- Toyota T-SB-0086-13: repeated ABS and TRAC warning light with C1231 on Bosch ABS/VSC (2009-2011 Camry)
- Last reviewed
- Written by
- Saurabh K.
- Editorial review
- Pending
- Technician review
- Technician review pending
This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error