The U0124 code is a specific diagnostic trouble code (DTC) that indicates a communication problem between your vehicle’s main computer systems and the lateral acceleration sensor module. This sensor plays a crucial role in your car’s stability and traction control systems by measuring side-to-side movements. When communication is lost, it can lead to issues with these safety features, making it important to address.
U0124 quick overview
| Meaning | U0124 – Lost Communication with Lateral Acceleration Sensor Module |
| Is it serious? | Yes, this code can affect the vehicle’s safety and handling features. |
| Possible causes | – Faulty lateral acceleration sensor – Issues with the vehicle’s battery or electrical system – Damaged wiring or connectors in the CAN bus system – Incorrectly placed fuses or relay issues |
| How to diagnose? | Inspect connectors and wiring for damage or dirt. Check all grounds and electrical system health, including the battery. Ensure correct fuse placement for related sensors. Measure resistance in CAN bus wires and check for shorts. Consider the health of the battery, as weak or faulty batteries can cause communication issues. Investigate the ABS module for any corrosion or connection issues. |
U0124 Meaning
When you see the U0124 code, it means there’s a hiccup in how your car’s brain talks to the part that detects how fast you’re turning or if you’re sliding. This might not seem like a big deal, but it’s essential for keeping the car stable on the road, especially in bad weather or sudden turns. The cause could be as simple as a bad battery or as complex as a problem with the car’s wiring. Fixing it usually involves checking the electrical system thoroughly, ensuring all connections are clean and secure, and that the battery is in good shape.
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- Car Electrical basics
- OBD-II scanner basics
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- OBD scanner buyer’s guide + discounts
How to fix U0124 – learn from mechanics
I looked into U0124 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.
Case #1: Pontiac
Vehicle Information 2009 Pontiac Vibe AWD 2.4L
Issue + Repair History
- ABS light on with multiple communication bus codes: U0073, U0123, U0124, U0126.
- Followed flowchart for 2008 model year, checking CAN wires and ground at DLC.
- Initially found resistance within acceptable range, but upon wiggling battery cables, resistance increased significantly.
- Recommended starting with battery replacement due to loose plates.
Other OBD2 Codes + Test Results
- U0073: Control Module Communication Bus Off
- U0123: Lost Communication with Yaw Rate Sensor Module
- U0124: Lost Communication with Lat. Acc. Sensor Module
- U0126: Lost Communication with Steering Angle Sensor Module
Mechanic Suggestions
- Inspect connectors and wiring harness for looseness or dirt, especially around ECUs.
- Check all grounds thoroughly.
- Consider the possibility of a weak or bad battery causing obscure faults and multiple codes.
- Pay attention to battery terminal connections, even if the battery cranks strongly.
Final Fix Replacing the battery resolved the issue, suspected to be caused by loose plates within the battery.
Case #2: Lexus
Vehicle Information 2007 Lexus IS250 2.5L
Issue + Repair History
- Car came in after hitting curb, requiring replacement of both front lower control arms, right front steering knuckle, and tie rods.
- Two weeks later, returned for rear brakes, oil change, and control arm bushings.
- Upon starting, multiple dash lights illuminated (ABS, VSC, PS, TPS), car wouldn’t shift out of park without using interlock release, and no power steering.
- Codes: U0123, U0124, U0126 – no communication with yaw rate sensor, lateral acceleration sensor, or steering angle sensor.
- Attempted steering angle recalibration and zero point calibration on yaw sensor with no success.
- Fuse for yaw rate sensor found in wrong fuse hole, corrected placement.
Other OBD2 Codes + Test Results
- U0123: Lost Communication with Yaw Rate Sensor
- U0124: Lost Communication with Lateral Acceleration Sensor
- U0126: Lost Communication with Steering Angle Sensor
Mechanic Suggestions
- Ensure correct fuse placement for yaw rate sensor.
- Try fully depleting the system by disconnecting the battery for an extended period.
- Check for ABS codes and clear them if necessary.
- Investigate for any network issues affecting communication between sensors.
Final Fix After finding no voltage at the yaw rate sensor, revisited the fuse location and discovered it was incorrectly placed due to the customer’s attempt to fix a trunk button issue. Corrected the fuse placement, restoring power to the yaw rate sensor and resolving the issue.
Case #3: Toyota
Vehicle Information 2006 Toyota Highlander 2.4L
Issue + Repair History
- Vehicle required a jump start every time it was turned off.
- Codes U0073, U0123, U0124, U0126 won’t clear; they immediately come back on after clearing.
- Installed a new battery.
Other OBD2 Codes + Test Results
- OBD2 Codes: U0073, U0123, U0124, U0126
- Test Results: Tested power – Fuses were found to be good.
Mechanic Suggestions
- Check CAN bus wire for disconnection and short circuits.
- Measure resistance according to specified values.
- If resistance values are not within specifications, perform further checks to identify the issue.
- Suspect a bad skid control module which the U codes suggest.
- Follow the provided procedure to diagnose the problem with the CAN bus wiring.
- If the vehicle doesn’t start and there’s a possibility of crossed battery terminals on a jump, consider replacing the fuse/relay panel in the left fender well.
Final Fix
- Corroded connector at the ABS module was cleaned, and the light has stayed off.
How to diagnose U0124
I made you an overview of solving this DTC, based on all the advice that was suggested by certified mechanics to address this issue in previously mentioned service cases.
| Diagnostic Step | Explanation |
|---|---|
| Inspect connectors and wiring | Look for looseness, dirt, or damage that could impair communication. |
| Check battery and electrical connections | Loose or damaged battery terminals can cause erratic electrical issues. |
| Ensure correct fuse and relay placement | Misplaced fuses can disrupt sensor operation and communication. |
| Disconnect battery to reset system | Helps clear persistent codes and recalibrate sensors. |
| Measure resistance in CAN bus wires | Identifies potential issues with the communication network. |
| Clean corroded connectors | Corrosion can hinder signals, especially at crucial modules like ABS. |
Each case highlights the importance of thorough diagnostics, considering both simple fixes like battery replacement and more in-depth checks like wiring inspection and fuse verification. These steps are crucial for addressing U0124 and related communication issues effectively.
Car Diagnostics Training
- Car Electrical basics
- OBD-II scanner basics
- How to use an OBD reader
- Introduction to a Bi-directional Scan tool
- OBD scanner buyer’s guide + discounts
I test OBD-II scanners and make DIY Engine diagnostics guides to help you solve your car problems without having to depend on the mechanic. A lot of them will try to scam you or are just no help at all. About Juraj Lukacko