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DTC codes / U01xx · Lost communication with a control module / U0148

U0148Lost Communication With Gateway 'C'

U0148 means the engine control module or another primary module has lost communication with a gateway module designated 'C' over the vehicle's controller area network (CAN) data bus. The computer detected that expected periodic messages from that gateway stopped arriving within the allowed time window, which sets the code and usually turns on the warning light.

SystemNetwork
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyProfessional
AreaLost communication with a control module

Symptoms you may notice

  • Warning light on the dashboard, often the check engine light or a network communication warning
  • Often no symptoms besides the warning light if the lost gateway is not critical to engine operation
  • Multiple unrelated warning lights or messages appearing at the same time
  • Intermittent operation of accessories or features controlled through the gateway
  • A no-start condition or stalling if the gateway is part of the immobilizer or power mode path
  • Scan tool cannot communicate with some modules even though others respond normally

Common causes, most likely first

  1. Damaged, corroded or loose wiring or connector pins on the CAN bus at the gateway or a splice point
  2. Failed gateway module 'C' due to internal fault, water intrusion or power/ground loss
  3. Blown fuse or poor ground supplying the gateway module
  4. CAN bus short to ground, short to voltage or open circuit between modules
  5. Another module on the same bus holding the network down and preventing gateway messages
  6. Aftermarket accessory wired into the CAN bus and disrupting communication
  7. Software or configuration mismatch after module replacement or battery service

How to diagnose and fix it

  1. Connect a scan tool and record all stored codes in every module, not just the engine computer
  2. Verify battery voltage and condition, then check the fuse and ground for gateway 'C'
  3. Inspect the gateway connector and nearby harness for corrosion, chafing or pushed-out pins
  4. Measure CAN bus resistance and voltage at the diagnostic connector to check for shorts or opens
  5. Disconnect suspect modules one at a time to see if communication returns
  6. Perform a network integrity or module presence test with a factory-level scan tool
  7. Repair wiring or replace the gateway module, then clear codes and verify communication persists through a drive cycle

Gateway faults that mimic other failures

  • A gateway module that loses power or ground can set U0148 while the module itself is still good, so always check fuses and grounds before condemning it.
  • One failed module on the CAN bus can prevent the gateway from communicating and set this code, so the fault may not be at the gateway at all.
  • Aftermarket alarms, remote starters or dash cameras tapped into the bus are a common missed cause of intermittent U0148.
  • Some vehicles set U0148 after battery replacement or module programming because the gateway needs reconfiguration or a relearn.
  • The code does not always mean the gateway is dead; a loose connector pin or chafed wire can cause the same lost-message condition.

Can I keep driving with U0148?

If the vehicle starts, runs and drives normally, you can usually drive it to a repair shop, but avoid long trips and expect that some electrical features may not work. If the engine stalls, will not start or multiple safety systems are disabled, stop driving and have the vehicle towed.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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