U0126 on Mitsubishi: How to Diagnose & Fix
Lost Communication With Steering Angle Sensor Module
1 Mitsubishi model · 1 documented issue · 1 critical
U0126 on Mitsubishi by model: symptoms, diagnosis and fix
Early Eclipse Cross models with Forward Collision Mitigation brake hard for objects that are not there. This is not just owner perception — NHTSA recall 18V620000 covers 2018-2019 Mitsubishi vehicles whose FCM-ECU software applies braking for longer than needed even after a pedestrian is no longer detected, with the stated consequence that drivers brake harder in response and increase rear-end collision risk. Companion recall 18V621000 covers a hydraulic unit ECU software defect on 2018 Eclipse Cross that may prevent automatic emergency braking, ABS, electronic stability control and Brake Auto Hold from working properly. Owner complaints go beyond the recall scope: filings describe adaptive cruise control triggering FCM braking when cresting hills with nothing ahead, and repeated multi-warning-light events with hard braking recurring several times a year despite dealer repairs. The camera-and-radar fusion is sensitive to road crown, overhead signs and reflective surfaces, and the system's brake authority is high enough that a false trigger at highway speed is genuinely hazardous.
Common Symptoms
- Vehicle brakes hard with no object ahead
- False forward collision warning alarms at any speed
- Braking triggered when cresting a hill on adaptive cruise
- Multiple dashboard warning lights flash simultaneously
- FCM, ASC and ABS warning lights on together
- Automatic emergency braking or Brake Auto Hold inoperative
How to Fix
First, run the VIN against NHTSA recalls and have both 18V620000 (FCM-ECU reprogram, Mitsubishi reference SR-18-007) and 18V621000 (hydraulic unit ECU reprogram, reference SR-18-008) performed free of charge if not already applied. If phantom braking persists after the reflashes, the next step is a windshield-camera aim and calibration — a replaced or improperly calibrated windshield is a very common cause of false triggers, and the camera requires a targeted static or dynamic aiming procedure, not just a mount swap. Check the front radar sensor behind the lower grille for physical misalignment, ice packing or a bent bracket from minor parking contact. As a temporary measure the FCM system can be switched off from the vehicle settings menu before each drive, though it re-arms at every ignition cycle.
Sources for this issue (3)
U0126 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does U0126 mean on a Mitsubishi?
U0126 stands for "Lost Communication With Steering Angle Sensor Module." Sets when a module loses data-bus communication with the Steering Angle Sensor Module, which provides steering position to the stability system, and no longer receives its expected messages. On Mitsubishi it is documented across 1 model: Eclipse Cross.
What are the most common causes of U0126?
The most common causes of U0126 are: Open or shorted bus wiring to the steering angle sensor module, Corroded or loose connector (often in the clockspring circuit), Blown fuse / lost power or ground, Low battery voltage, Failed steering angle sensor module. The specific cause varies by vehicle.
How much does it cost to fix U0126 on a Mitsubishi?
Repair costs vary widely with the root cause and Mitsubishi model; each issue on this page carries its own estimate where one is published.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.