C1391 code in owner complaints

Code C1391 is named in 391 US owner complaints. Models: 21, model years 2004–2024.

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 C1391: 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 391 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: 391
Models: 21
Model years: 2004–2024

Which models and years

Models whose owners name this code (21). Years link to the model year problems page.

Model	Years	Complaints
Toyota Prius	2004, 2005, 2006, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015	219
Toyota Prius V	2012, 2013, 2014, 2015	46
Toyota Highlander	2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013	29
Lexus CT	2011, 2012, 2013, 2014, 2015	22
Toyota Highlander Hybrid	2006, 2007, 2008, 2010, 2012	20
Toyota Camry Hybrid	2007, 2008, 2013	14
Toyota Prius C	2012, 2013, 2014	7
Toyota Prius Plug-IN Hybrid	2010, 2012, 2013, 2014	7
Toyota Camry	2007, 2009	6
Lexus ES	2013, 2014, 2015	5
Lexus RX Hybrid	2006, 2010, 2013	4
Lexus HS	2010	2
Lexus LS460	2009, 2013	2
Lexus ES Hybrid	2013	1
Lexus HS 250 Hybrid	2010	1
Lexus LS	2013	1
Lexus LS460L	2009	1
Lexus LX	2024	1
Lexus RX	2007	1
Toyota Avalon Hybrid	2015	1
Toyota RAV4	2020	1

Components named together with the code

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

Service brakes 385
Forward collision avoidance 26
Electrical system 22
Electronic stability control 19
Vehicle speed control 16
Other 15
Engine 3
Fuel/propulsion system 3

Complaints by model year

2004 2
2005 1
2006 15
2007 20
2008 28
2009 11
2010 72
2011 36
2012 71
2013 73
2014 36
2015 24
2020 1
2024 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.

Luckily, without causing an accident or injury, we made it to the shoulder and called a tow truck. Was able to get it to Lexus and the vehicle was diagnosed with DTC C1391.
Lexus ES 2015 · 2026-11
An independent mechanic inspected the vehicle but could not retrieve a diagnostic code at that time. On November 1, 2026, an ABS diagnostic scan at O'Reilly Auto Parts confirmed trouble code C1391, "Abnormal Leak of Accumulator Pressure." The diagnostic report recommended replacement of the brake booster and master…
Toyota Prius 2012 · 2026-11
This pump activity occurred without brake warning lights and without diagnostic trouble codes at that moment. Prior to actuator replacement, the vehicle had repeatedly set brake system codes including: C1391 â Accumulator internal leak C1241 â Low battery voltage caused by pump overrun C1319 â Brake control…
Lexus LS 2013 · 2026-10

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.