Communication between modules
U codes: the modules in the car have stopped hearing each other. This is almost never fried electronics — usually a terminal, a ground or a flat battery.
20 codes in this section, 20 with a guide
What it usually turns out to be
- Many U codes at once mean the power supply, not ten broken modules.
- If they appeared after a wash or a repair, check connectors first, not the module.
- Check the system voltage with the engine running: 13.8–14.6 V.
U0001High speed CAN bus — general malfunctionguideU0073CAN bus off — module went into protectionguideU0074Second CAN bus — no communicationguideU0100Lost communication with engine control moduleguideU0101Lost communication with transmission control moduleguideU0121Lost communication with ABS/ESP moduleguideU0122Lost communication with stability control moduleguideU0126Lost communication with steering angle sensorguideU0131Lost communication with electric power steeringguideU0140Lost communication with body control module (BCM)guideU0151Lost communication with airbag control moduleguideU0155Lost communication with instrument clusterguideU0159Lost communication with parking sensorsguideU0164Lost communication with climate control moduleguideU0167Lost communication with immobiliserguideU0184Lost communication with radio/infotainmentguideU0401Invalid data from engine control moduleguideU0415Invalid data from ABS moduleguideU0416Invalid data from stability control moduleguideU0422Invalid data from body control moduleguide
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Other sections
Fuel and air metering, general 33Intake measuring sensors 17Oxygen sensors 19Throttle and accelerator pedal 15Mixture: lean and rich 11Fuel and air metering: injectors 25Ignition system and misfires 29Exhaust gas recirculation (EGR) 7Secondary air injection 3Catalytic converter 4Canister and purge valves 9Fuel vapour leaks 7Fuel level in the tank 4Diesel particulate filter 6Idle and auxiliary systems 22Control module and its circuits 21Transmission 17Brakes, ABS and stability control 17Body, airbags and lighting 12