OBD-II code · Network
U049B Invalid Data Received From Tachograph Module
A receiving module detected implausible data from the digital tachograph module (commercial vehicle driving-time recorder). Speed, distance or driver-card values fail plausibility checks and are rejected.
Is it safe to drive with U049B?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyModule internal fault or sensor input drift
- PossibleSoftware version mismatch after replacement
- Less likelyGateway module routing CAN messages incorrectly
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.5–3 h
- Emissions test
- Usually unaffected
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Tachograph Module
Related codes
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- U0499Invalid Data Received From Telematic Control Module
- U049AInvalid Data Received From Door Control Module A
- U049CInvalid Data Received From Battery Charger Control Module A
- U049DInvalid Data Received From Glow Plug Control Module 2
- U049EInvalid Data Received From Direct Ozone Reduction Catalyst Temperature Sensor
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.