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DTC codes / U01xx · Lost communication with a control module / U0124

U0124Lost Communication With Lateral Acceleration Sensor Module

U0124 is a communication fault, not a sensor fault: the module that monitors your vehicle's sideways (lateral) acceleration has stopped reporting to other computers over the controller area network (CAN) bus. The computer that set the code knows only that the expected periodic message from the lateral acceleration sensor module went missing, so it cannot tell whether the sensor died, its wiring failed, or the network itself is disturbed.

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

Symptoms you may notice

  • Anti-lock brake (ABS) and stability control warning lights illuminated, often together with a traction control light
  • Electronic stability control (ESC) disabled, with the dash warning that the system is off
  • Hill-start assist, rollover mitigation or adaptive suspension features dropping out because they share the same sensor data
  • A stored code with no drivability change at all, since the engine and transmission do not depend on this signal
  • Occasional warning light that clears after a restart and returns later, typical of an intermittent bus fault
  • Speedometer, ABS and stability functions behaving normally in dry straight-line driving, masking the fault

Common causes, most likely first

  1. Corroded, loose or pushed-back pins in the connector at the lateral acceleration sensor module, usually under a seat or in the centre console where spills and moisture collect
  2. Damaged or chafed wiring in the CAN bus or power/ground circuit feeding the sensor module, often from seat movement or trim removal
  3. A failed lateral acceleration sensor module that has lost internal power or its bus transceiver
  4. Low or unstable battery voltage, or a poor ground shared with the sensor module, causing it to drop off the network
  5. A second module on the same bus shorting the CAN lines and disrupting communication for the sensor module
  6. Water intrusion into the sensor's mounting location or its connector after a leak or flood repair
  7. A module that was disconnected during interior work and never reconnected or reinitialised

How to diagnose and fix it

  1. Scan all modules and record every stored code, because U0124 rarely travels alone and companion codes point to the real circuit
  2. Inspect the lateral acceleration sensor module connector for corrosion, bent pins and moisture, then clean and reseat it
  3. Check battery voltage and the sensor module's power and ground at the connector with a multimeter under load
  4. Measure CAN bus resistance and voltage at the sensor connector to confirm the bus is intact and not shorted
  5. Wiggle-test the harness while watching live data or the communication status to expose an intermittent break
  6. Repair or replace damaged wiring and connectors, then clear codes and verify the module reports again
  7. If wiring and power check out, substitute a known-good sensor module and recheck communication before condemning the original

Why the sensor is often not the culprit

  • U0124 describes a missing message, so a perfectly healthy sensor will set it if its connector is unplugged or its ground is corroded; technicians who replace the sensor first frequently see the code return.
  • The lateral acceleration sensor is commonly mounted under a front seat or in the centre console, which makes it vulnerable to spilled drinks, wet floor mats and seat-track damage that a visual inspection from above will miss.
  • A weak battery or failing ground can drop one module off the bus intermittently, so the code may appear only on cold starts and vanish once charging voltage recovers.
  • Another module shorting the CAN lines can silence the lateral acceleration sensor module, so a no-communication code here sometimes traces to an unrelated component on the same network.
  • On vehicles where the yaw rate and lateral acceleration functions live in one combined module, the same part can set U0124 alongside yaw-rate communication codes, and both should be treated as one circuit.

Can I keep driving with U0124?

The vehicle remains drivable because stability control and ABS-related functions are disabled, but you lose electronic stability assistance and should avoid aggressive cornering, wet or slippery roads, and towing until communication is restored. If the ABS warning is also lit, treat braking assist features as reduced and get the fault diagnosed promptly.

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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