OBD-II Diagnostic Trouble Code
U0126 — Lost Communication With Steering Angle Sensor Module
U0126 means a module lost communication with the steering angle sensor module. Steering angle is used by stability control and some driver-assist and lane systems. The sensor is usually on the steering column, often near the clockspring.
Severity 3/5
Truck-relevant
Service this week
Severity
Service this week
Lost Communication With Steering Angle Sensor Module
Code
U0126
Category
Network
Subsystem
Network
Truck-relevant
Yes
What this means for truckers
U0126 (Lost Communication With Steering Angle Sensor Module) — SAS for ESC is offline.
Before you replace parts — try this first
U0126 on the Network system is most often loose or damaged steering angle sensor connector — not a dead part. On commercial diesels especially, work these in order before spending money on parts:
- Confirm the symptoms. Match what your truck is doing to the Symptoms section below. If the code is set but the symptoms are not there, clear the code and re-test after a drive cycle — it may not return.
- Clean and dry the sensor connector. Water, road salt, or oil seeping into a connector is the #1 fake sensor failure. Disconnect, look for green corrosion or moisture, spray with electrical contact cleaner, dry, reseat. Many faults clear here for $0.
- Inspect the wiring harness. Trace the wire from the sensor toward the ECM — look for chafing against the engine block, melted insulation near the turbo or exhaust, or pinch points where a clamp has rubbed through.
- Test the sensor before swapping it. Most Common Causes (below) list the expected voltage or resistance range — a $20 multimeter saves a $300 sensor swap that does not fix the problem.
- Only then, replace the part. Use the OEM or a tier-1 aftermarket. Cheap sensors throw the same code in two weeks.
Symptoms
Stability and traction control warnings and disabled stability functions. Some trucks also show lane-keeping or driver-assist warnings.
Common causes
- CommonLoose or damaged steering angle sensor connector ($100–$400)
- OccasionalSensor power or ground fault ($50–$300)
- OccasionalFailed steering angle sensor ($300–$900)
- OccasionalWiring damage in the steering column ($150–$600)
How to fix
Check sensor connector, power and ground
When to use: First step
Inspect column wiring for damage
When to use: After steering column or dash work
Replace the sensor and perform steering angle calibration
When to use: When wiring is good but the sensor is silent
Affects most
No specific vehicle pattern found in our complaint database. This code can appear on any vehicle that supports OBD-II diagnostics.
Related
- → Browse all DTC trouble codes
- → Decode a VIN to check codes for your truck
- → Owner-operator maintenance guides
- → U0100 — Lost Communication With ECM/PCM A
- → U0101 — Lost Communication With TCM
- → U0102 — Lost Communication With Transfer Case Control Module
- → U0103 — Lost Communication With Gear Shift Module
- → U0104 — Lost Communication With Cruise Control Module
Frequently Asked Questions
Can I drive with code U0126?
U0126 is severity 3 — plan service within a few days. Performance is likely degraded already (you may feel reduced power, harsher shifts, or slightly worse fuel economy). Continuing to drive risks additional damage to adjacent components.
How much does it cost to fix U0126 on a commercial truck?
Total repair cost ranges $50–$900 depending on the root cause. The cheapest fix is usually the first one listed below — Loose or damaged steering angle sensor connector — which is also the most common. On commercial trucks the cost is usually higher than passenger vehicles due to part availability and shop labor rates ($120–185/hour at most truck shops, vs $90–130 at general auto shops). DIY-capable fixes (sensors, hoses, filters) are at the low end; major component replacements (turbo actuator, high-pressure fuel pump, transmission solenoid pack) are at the high end. Always diagnose with a scan tool BEFORE replacing parts — guessing wrong on a $1,500 turbo actuator when the actual issue was a $30 boost hose is a common expensive mistake.
Will U0126 fail a DOT inspection?
U0126 is generally not a direct DOT inspection fail item by itself. Inspectors focus on safety-critical systems (brakes, steering, tires, lights, hours-of-service). However, the check engine light alone can trigger additional inspection scrutiny. Best practice: fix the code and clear it before a planned inspection.
What's the difference between U0126 and related codes?
U0126 is closely related to: U0100 (Lost Communication With ECM/PCM A), U0101 (Lost Communication With TCM), U0102 (Lost Communication With Transfer Case Control Module), U0103 (Lost Communication With Gear Shift Module). These codes share the same subsystem (network) and often appear together. If you see this code, scan for the full code list — fixing the root cause usually clears multiple companion codes at once. If only U0126 is set without the companions, the issue is more isolated.
How do I prevent U0126 from coming back after a repair?
For U0126 (Lost Communication With Steering Angle Sensor Module), prevention centers on the network system. Pay attention to ground connections at every PM — bad grounds are 70% of communication codes. Inspect harness routing for chafe points. Don't disconnect modules with the key on.