OBD-II Diagnostic Trouble Code
U0431 — Invalid Data Received From Smart Cruise Control
U0431 means a module received invalid data from the smart cruise control system, the adaptive cruise radar or distance controller. The message arrived but distance, target or status data was implausible. A misaligned, blocked or faulty sensor is a common reason.
Severity 2/5
Truck-relevant
Service soon
Severity
Service soon
Invalid Data Received From Smart Cruise Control
Code
U0431
Category
Network
Subsystem
Network
Truck-relevant
Yes
What this means for truckers
Service this week on a Cummins X15, Detroit DD15, PACCAR MX-13. Not an immediate stop, but ignoring it usually leads to a more expensive fix downstream.
Before you replace parts — try this first
U0431 on the Network system is most often radar sensor out of alignment from minor impact or bumper damage — 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
Adaptive cruise and collision warning are disabled or unavailable, and a warning may show on the cluster. Standard cruise may or may not still work depending on the vehicle.
Common causes
- CommonRadar sensor out of alignment from minor impact or bumper damage ($200–$600)
- CommonSensor face blocked by dirt, ice, snow or a bumper cover ($0–$100)
- OccasionalWiring or connector problem at the sensor ($150–$600)
- OccasionalFaulty radar sensor ($1000–$3500)
How to fix
Clean the radar sensor face and check for obstruction
When to use: First step, especially in winter
Check the sensor mounting and perform a radar alignment with the manufacturer's procedure
When to use: After front-end damage or when the fault persists
Inspect the wiring and connectors
When to use: When alignment is correct
Replace and calibrate the radar sensor
When to use: After other causes are ruled out
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
- → U0401 — Invalid Data Received From ECM/PCM A
- → U0402 — Invalid Data Received From TCM
- → U0403 — Invalid Data Received From Cruise Control Module
- → U0415 — Invalid Data Received From ABS Control Module
- → U0418 — Invalid Data Received From Brake System Control Module
Frequently Asked Questions
Can I drive with code U0431?
U0431 is severity 2 — service this week. Not an immediate stop, but ignoring it usually compounds the problem. Most common cause for this code is a worn sensor or minor performance fault that won't strand you today but will get more expensive the longer you wait.
How much does it cost to fix U0431 on a commercial truck?
Total repair cost ranges varies depending on the root cause. The cheapest fix is usually the first one listed below — Radar sensor out of alignment from minor impact or bumper damage — 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 U0431 fail a DOT inspection?
U0431 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 U0431 and related codes?
U0431 is closely related to: U0401 (Invalid Data Received From ECM/PCM A), U0402 (Invalid Data Received From TCM), U0403 (Invalid Data Received From Cruise Control Module), U0415 (Invalid Data Received From ABS Control 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 U0431 is set without the companions, the issue is more isolated.
How do I prevent U0431 from coming back after a repair?
For U0431 (Invalid Data Received From Smart Cruise Control), 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.