The general meaning of the U1004 Code is not helpful and it is found online. The general meaning of the code is available online. The general/automobile meaning of the code is U for Network Code Problem is climate control system, lighting, airbags, etc. 1 for MFG – Manufacturer Specific. 0 for Fuel And Air Metering. 0 for IC Circuit High Voltage and 4 for Cruise Vehicle Speed/Set Speed Difference Too High. The U1004 engine code appears a kind of network problem and it is not difficult to solve the car engine problem. An automobile engineer can easily fix the car engine problem if he has expertise.