C1391
ABS / stability-control fault code, listed for 2 vehicle lines from Toyota. What it means on each one, with sources, and when the module is the cause.
What C1391 means
Brake actuator internal fluid leak condition (with C1252/C1253/C1256) per Toyota T-SB-0032-16, which applies to 2006-2007 Highlander HV
On: 2006-2007 Toyota Highlander Hybrid (MHU23/MHU28)
Stored with brake/ABS/TRAC lights or 'Check VSC' when the brake actuator has a small internal fluid leak (Toyota T-SB-0032-16)
On: 2004-2009 Toyota Prius (XW20, Gen 2)
Is it the ABS module?
Check the cheap things first: battery voltage and the main fuses for the ABS pump and module, the ground straps, the module connector (corrosion, a pushed-back pin) and, for wheel-speed codes, the sensor and its wiring at each wheel. If those are good and the code returns as soon as it is cleared — or the scan tool cannot talk to the ABS module at all — the module itself is the likely cause, and that is what we repair.
Vehicles that set C1391
C1391 by vehicle
What does C1391 mean on a Toyota Highlander Hybrid (MHU23/MHU28)?
The source we cite for the 2006-2007 Toyota Highlander Hybrid (MHU23/MHU28) lists it as: Brake actuator internal fluid leak condition (with C1252/C1253/C1256) per Toyota T-SB-0032-16, which applies to 2006-2007 Highlander HV. That vehicle uses HYBRID brake actuator assembly. We repair it as part of the Hybrid brake actuator (brake booster with pump) family, quote.
What does C1391 mean on a Toyota Prius (XW20, Gen 2)?
The source we cite for the 2004-2009 Toyota Prius (XW20, Gen 2) lists it as: Stored with brake/ABS/TRAC lights or 'Check VSC' when the brake actuator has a small internal fluid leak (Toyota T-SB-0032-16). That vehicle uses HYBRID brake actuator (high-pressure accumulator + pump, electronically controlled braking) - not a conventional ABS mod. We repair it as part of the Hybrid brake actuator (brake booster with pump) family, quote.
Still not sure?
Send us C1391, a photo of the module label and your VIN — we tell you whether the module is the likely cause and what it costs, before you pull anything. Asking costs nothing.
C1391 keeps coming back after the checks? Fix the module — from $499.
Look up your part number and order online — we email you a prepaid label to our lab. Or send us a photo of the label and your VIN first, and we'll tell you what you have and what it costs.
Back with your VIN and coding · can’t be repaired? repair price back, minus shipping · 1-year warranty · rush 2–3 days +$100
Call (817) 505-4201 · 📱 Text us a photo of the module label · Ask first — send a label photo · Email repairs@absmodulelab.com