U0133 code meaning
Lost Communication With Active Roll Control Module
What U0133 means
U0133 indicates that the active roll control module, which drives hydraulic or electromechanical anti-roll bars to reduce body lean in corners, no longer answers on the bus. No manufacturer publicly ties U0133 to that module: Saab's 2011 9-5 list uses the number for its air suspension control module instead, so older vehicles may interpret it differently. Systems of this kind exist, for instance on the Bentley Bentayga, where the adaptive suspension unit J775 acts as master for the roll stabiliser units J924 (front axle) and J1096 (rear axle) and their software must match (TPI 2055643). Invalid roll-module data is U0434; suspension modules A and B lose contact under U0132 and U0139. Expect a chassis warning and noticeably more body roll.
U0133 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyHard
- Typical labor0.5 to 5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0133
- Chassis or suspension warning lamp
- More body roll when cornering
- Sport or dynamic driving modes unavailable
Common causes of U0133
- Most likelyFuse, supply, ground or CAN wiring of the roll control module faulty
- PossibleSoftware of master and stabiliser units not compatible after a replacement (Bentley TPI 2055643)
- Less likelyRoll control module internally faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Active roll moduleCAN bus wiring
What each part of U0133 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 33 | The exact fault in that area. |
What to do next
- Note U0133 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U0133
What does U0133 mean?
U0133 means "Lost Communication With Active Roll Control Module". U0133 indicates that the active roll control module, which drives hydraulic or electromechanical anti-roll bars to reduce body lean in corners, no longer answers on the bus. It is a generic code, so it means the same on every make.
Is it safe to drive with U0133?
U0133 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U0133 fail an emissions test?
U0133 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U0133 to fix?
Difficulty: hard. A typical repair takes 0.5 to 5 hours of work. This is a job for a workshop.
Will U0133 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.