CAN network

U0144 — Lost Communication with Gateway Module A

Severity: medium Drive with care, to a shop

What U0144 means

One or more control modules stopped receiving messages from Gateway Module A. The gateway links the vehicle's separate CAN networks, such as powertrain, body and infotainment, and passes data between them. When it goes offline, modules can't talk to each other and lost-communication codes get stored.

Symptoms

  • Many modules stop responding at the same time
  • No-start on some vehicles
  • Several warning lights on at once
  • Functions of the affected module don't work
  • Scan tool can't see some modules or shows many U-codes

Possible causes

  1. Failed gateway module
  2. Damaged CAN-H or CAN-L wiring (open, short, chafed harness)
  3. Aftermarket alarm or other accessory spliced into the CAN bus
  4. Faulty control module loading down the bus
  5. Corroded connectors or terminals
  6. Power supply or ground fault at the gateway or other modules
  7. Low battery voltage or electrical system instability

How to diagnose

  1. Check battery condition and system voltage, and rule out voltage drops at key-on
  2. Run a full-module scan and map which modules respond and which don't
  3. Record all codes and freeze-frame data, clear them, and see which return
  4. Inspect connectors and harnesses at the gateway and silent modules for corrosion, moisture, chafing or tampering
  5. Check fuses, power and ground circuits of the gateway using the wiring diagram
  6. Measure resistance between CAN-H and CAN-L at the diagnostic connector (about 60 ohms is normal) and check each line's voltage
  7. Find and remove aftermarket accessories (alarm, head unit, tracker) and see if the fault clears
  8. Unplug suspect modules one at a time, only following a documented factory procedure, while watching the bus

Common fixes

  • Repair the damaged CAN wiring section or replace the connector
  • Clean or replace corroded terminals and restore gateway power and ground
  • Remove improperly installed alarm or accessory wiring
  • Replace a faulty module that is loading the bus
  • Replace or reprogram the gateway and code it to the vehicle

Questions and answers

What does U0144 mean?

It means communication with Gateway Module A was lost. That's the module that passes data between the CAN networks, so other modules can no longer exchange information properly.

Can I drive with U0144?

If the car runs normally, you can usually drive it to a shop. Safety systems or engine starting may fail, though, so don't delay diagnosis.

Is the gateway always the culprit?

No. Wiring faults, poor power or ground, and aftermarket devices on the bus are common causes. Check those first before replacing the gateway.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.