C1203 code in owner complaints

Code C1203 is named in 19 US owner complaints, 1 of them (5%) after a crash. Models: 6, model years 2002–2014.

There is little data for this code or its meaning is ambiguous, so this page is not indexed.

What the code means

This is a manufacturer-specific code: the meaning depends on the make and sometimes on the year.

How to read C1203: the letter C means chassis (brakes, ABS, steering, suspension); the second digit 1 marks a manufacturer code whose meaning is set by the make; the last three characters 203 identify the specific fault.

ABS/ESC codes: wheel speed sensors, the ABS hydraulic unit and pump, brake booster, pressure and yaw sensors. A hit to a wheel or suspension often damages the wheel speed sensor or its wiring, so on a damaged car this code is a reason to inspect the hub, knuckle and control arms, not just swap the sensor.

Key figures

Complaints with this code: 19
after a crash: 1 (5%)
Models: 6
Model years: 2002–2014

Which models and years

Models whose owners name this code (6). Years link to the model year problems page.

Model	Years	Complaints
Toyota Sequoia	2002, 2003, 2004	12
Toyota Sequoia SR5	2003	3
Hyundai Santa FE Sport	2014	1
Toyota Highlander	2002	1
Toyota Prius C	2012	1
Toyota Tundra	2010	1

Components named together with the code

Component as the owner filed it (one complaint can list several).

Service brakes 8
Electronic stability control 6
Vehicle speed control 5
Electrical system 3
Other 3
Engine 1
Exterior lighting 1

Complaints by model year

2002 2
2003 13
2004 1
2010 1
2012 1
2014 1

What to do if an auction car has this code

Inspect the wheel and suspension on the impact side: the wheel speed sensor is often damaged together with the hub or knuckle.
Check whether the ABS and ESC lights stay on after start-up.
After replacing sensors or the hydraulic unit, bleeding and scan tool adaptation may be required.

What owners report

Excerpts of owner complaints in the original wording. Owner statements not verified by the regulator; personal data removed.

There were absolutely no warning lights or symptoms before I parked the vehicle. I had it towed to my local Hyundai dealership, and their diagnostic scan confirmed major brake and chassis issues, specifically code C2402 for an ABS Pump Motor Circuit Malfunction and codes C1200, C1203, and C1206 for a loss of wheel…
Hyundai Santa FE Sport 2014 · 2026-07
My specific codes are C1241 and C1203. Toyota told me I will need a new computer to controls those systems at a 921 dollar expense. These issues have been ongoing since 2009.
Toyota Sequoia 2002 · 2021-01
When driving the back light an traction control light come in brake light stays on an it says codes C1203 C1223 C1247 also saying the abs sensor on master cylinder open circuit also has a code fro 0dtc had it checked out on 7/1/2019
Toyota Sequoia SR5 2003 · 2019-07

Related codes

Sources: public official US data (owner complaints) and the SAE J2012 standard. Complaints are owner statements not verified by the regulator. A code from a complaint does not replace a scan tool diagnosis. Data updated 2026-11-10.