U0418 code meaning
Invalid Data Received From Brake System Control Module A
Network system Generic code U04xx codes Check engine light
What U0418 means
U0418 says a node rejects the content of frames from brake system control module A, on many cars the unit that combines ABS, stability control and brake boost. GM's 2025 tables are detailed: the engine controller tests brake status signals for bad counters, protection values or checksums, 8 faults in 18 checks give Type A with MIL after one trip; the TCM runs the same test as Type B, the BCM demands 15 bad of 16, and the front camera rates its check Special Type C and only disables adaptive cruise. Saab's 9-5 list adds sub-types 71, 72 and 74. FCA notes for the 2021 Jeep Cherokee 2.4 L that U0418 may set falsely below 10 V and reflashes the PCM (18-078-22); BrightDrop 24-NA-107 forbids repairs for it on the Zevo 600. U0129 is lost contact, U0318 software.
U0418 at a glance
- Check engine lightYes, usually on
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyHard
- Typical labor0.3 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0418
- Check engine light
- Adaptive cruise, stop-start or driver assistance unavailable
- Brake or stability warning in the cluster
Common causes of U0418
- Most likelyLow battery voltage (below about 10 V) during start or standstill
- PossibleEngine or transmission controller software reacting too sensitively; update available
- PossibleLoose connector or harness fault disturbing the chassis bus
- Less likelyBrake system control module internally faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Brake system control moduleCAN bus wiring
What each part of U0418 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 18 | The exact fault in that area. |
What to do next
- Note U0418 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U0418
What does U0418 mean?
U0418 means "Invalid Data Received From Brake System Control Module A". U0418 says a node rejects the content of frames from brake system control module A, on many cars the unit that combines ABS, stability control and brake boost. It is a generic code, so it means the same on every make.
Is it safe to drive with U0418?
Drive gently and only to a workshop. With U0418 the car can go into limp mode (reduced power) to protect itself.
Will U0418 fail an emissions test?
U0418 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U0418 to fix?
Difficulty: hard. A typical repair takes 0.3 to 4 hours of work. This is a job for a workshop.
Will U0418 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.