Toyota-specific code — factory diagnostic data| DTC Data Sheet | |
| Code | U0129 |
| Vehicle | 2014 Toyota RAV4 (XA40) |
| System | Audio And Visual System |
| Fault type | Communication |
| Official meaning | Lost Communication with Brake System Control Module |
| Source | 2014 Toyota RAV4 factory diagnostic information |
Definition source: Toyota factory description. Diagnostic guidance is based on factory-defined fault logic for this code.
U0129 on the 2014 Toyota RAV4 means: Lost Communication with Brake System Control Module. It is a communication code reported by the Audio And Visual System.
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Looking for the cross-vehicle definition? Read the generic U0129 article for the SAE-defined fault logic that applies to all manufacturers.
U0129 Quick Answer
U0129 on a 2014 Toyota RAV4 indicates Lost Communication with Brake System Control Module. Start with a freeze-frame check and a careful inspection of the connector and wiring at the affected device before replacing any parts.
What Does U0129 Mean on a Toyota RAV4?
On the 2014 Toyota RAV4, the Audio And Visual System sets U0129 when it detects a fault matching its official definition: Lost Communication with Brake System Control Module. This is a manufacturer-specific definition from Toyota factory diagnostic data and applies to the XA40-generation RAV4.
Symptoms
- Warning light for the affected system (check engine, ABS, airbag, or a system indicator depending on the module)
- Reduced or lost function of the audio and visual system
- Possible related codes from other modules on the RAV4 CAN/LIN network
Common Causes
- Fault in the component named in the definition (lost communication with brake system control module)
- Open, shorted, or high-resistance wiring in the affected circuit
- Connector corrosion, water ingress, or a backed-out terminal
- Loss of supply voltage or a poor ground at the device
- Module internal fault — confirm wiring and supplies before condemning the module
Diagnostic Approach
For U0129 on the 2014 Toyota RAV4 you’ll want a scan tool with Toyota-enhanced coverage (Techstream-class) — generic OBD-II readers usually will not read U-codes — plus a digital multimeter and the wiring diagram.
- Confirm the code is current, not stored history, and record freeze-frame data.
- Read all modules — related codes often pinpoint the root cause faster than the headline code.
- Inspect and wiggle-test the connector at the named device while watching live data.
- Measure supply voltage and ground integrity at the device; verify the circuit against the RAV4 wiring diagram.
- Substitute or isolate the suspect device only after wiring and supplies check out.
- Clear the code and road-test through one or two drive cycles to confirm the repair.
Possible Fixes
- Repair open/short/high-resistance wiring or a corroded connector
- Restore supply voltage or ground at the affected device
- Replace the failed component named in the definition
- Replace and, where required, initialise/program the module if it is internally faulty
Can I Still Drive With U0129?
It depends on the system. Audio And Visual System faults that affect braking, the airbag/restraint system, power steering, or stability control should be repaired before further driving. Comfort or convenience faults can usually be deferred briefly, but related codes can mask one another on the RAV4 network — diagnose promptly.
FAQ
Is U0129 specific to the Toyota RAV4?
The definition here is taken from 2014 Toyota RAV4 (XA40) factory diagnostic data. The same code may appear on other Toyota models, but the affected module and exact criteria can differ between platforms.
Can I clear U0129 without fixing it?
You can clear it, but if the underlying fault is still present the RAV4 will reset the code on the next drive cycle that runs the relevant monitor. Diagnose the cause first.
Will a generic OBD-II reader show U0129?
Often not — U-codes are manufacturer-specific and usually require a scan tool with Toyota-enhanced coverage such as a Techstream-class tool.
Source
Code definition from 2014 Toyota RAV4 (XA40) factory diagnostic information (Audio And Visual System). Symptom, cause, and diagnosis guidance summarised from standard OBD-II diagnostic practice for this platform.