OBD-II Diagnostic Trouble Code
U0418 — Invalid Data Received From Brake System Control Module
U0418 means a module received invalid data from the brake system control module. The message arrived but brake status, pressure or speed data was implausible, missing or failed integrity checks. Usually the brake controller has its own fault.
Severity 3/5
Truck-relevant
Service this week
Severity
Service this week
Invalid Data Received From Brake System Control Module
Code
U0418
Category
Network
Subsystem
Network
Truck-relevant
Yes
What this means for truckers
U0418 (Invalid Data Received From Brake System Control Module) — see existing entry.
Before you replace parts — try this first
U0418 on the Network system is most often active brake system fault such as a wheel speed or pressure sensor — 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
Brake, ABS or traction lights, cruise or engine brake disabled, and possibly speedometer or transmission issues on trucks that use brake module speed data. Base brakes normally still work.
Common causes
- CommonActive brake system fault such as a wheel speed or pressure sensor ($100–$600)
- OccasionalBrake switch or pressure switch giving implausible signals ($50–$300)
- OccasionalNetwork wiring or connector problem ($150–$600)
- RareBrake control module failure or software issue ($600–$2000)
How to fix
Read and repair brake module codes
When to use: First step
Check brake switch and pressure sensor inputs on a scan tool
When to use: When cruise drops out or brake status looks wrong
Inspect the network wiring and connectors at the brake module
When to use: When no brake codes are present
Reprogram or replace the brake control module
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
- → U0404 — Invalid Data Received From Gear Shift Control Module
- → U0415 — Invalid Data Received From ABS Control Module
Frequently Asked Questions
Can I drive with code U0418?
U0418 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 U0418 on a commercial truck?
Total repair cost ranges $50–$2000 depending on the root cause. The cheapest fix is usually the first one listed below — Active brake system fault such as a wheel speed or pressure sensor — 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 U0418 fail a DOT inspection?
U0418 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 U0418 and related codes?
U0418 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), U0404 (Invalid Data Received From Gear Shift 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 U0418 is set without the companions, the issue is more isolated.
How do I prevent U0418 from coming back after a repair?
For U0418 (Invalid Data Received From Brake System Control 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.