Chevrolet U1814: Powertrain High Speed Communication Enable Circuit

What Does The Chevrolet U1814 Code Mean?

The system voltage is between 9-16 volts. The vehicle power mode master requires serial data communication to occur.

What Are The Potential Causes Of The Chevrolet U1814 Code?

• Use the DMM MIN/MAX function to capture/locate intermittent conditions.
• Short to ground may also set multiple no communication codes for GMLAN high speed modules.
• Short to ground may also open the fuse feeding the ignition switch.

Recommended Parts

Below are some recommended auto parts to help you address the trouble code affecting your vehicle and get it running smoothly again:

>>> WORKPRO 582-piece Crimp Terminals, Wire Connectors, Heat Shrink Tube, Electrical Repair Kit
>>> GM Genuine Parts 12633238 Engine Control Module

Note: During the purchasing process, please check carefully whether the part you want to buy fits your car!

Reference Sources

• GM, 2014, Service Bullettin – Malfunction Indicator Lamp (MIL) On, Various DTCs Set, IPC Inoperative, Display and/or BCM Fuse Blown.
• GM, 2014, Service Bullettin – Unable to Clear BCM DTCs After Completing Repair.
• GM, 2015, Service Bullettin – Diagnostic Tips – Diagnosing High Speed LAN Concerns.
• GM, 2015, Service Bullettin – No Crank No Start Loss of Communication Engine Stall SES MIL DIC Messages Various Electrical
  Concerns.
• GM, 2020, Service Bullettin – PIT5713A SES MIL / IPC Gauges Sweep / IPC Warning Message /
  Reduced Engine Power / Loss Communication / Various DTCs (V6 Inspect Engine Harness).
• GM, 2020, Service Bullettin – Service All Wheel Drive (AWD)/Service Stability Messages and/or Low Oil Pressure
  Shut Off Engine Message Displayed in Driver Information Center (DIC), Erratic
  Speedometer Readings, Malfunction Indicator Lamp (MIL) Illuminated – DTC P0641,
  U0073, U0100, U0101, U0121, U0131, U0136 and/or U1814 Set.