U0405 code meaning
Invalid Data Received From Cruise Control Module
Network system Generic code U04xx codes Check engine light
What U0405 means
Today the module behind this code is usually the distance radar of adaptive cruise, the unit that asks the engine controller for speed and torque changes. U0405 is set when those requests arrive but fail the receiver's integrity checks. Saab's 2011 code list breaks it down into sub-codes 71 (invalid data), 72 (message counter) and 74 (checksum). Stellantis documents it on the 3.0 L Hurricane six: 2025 Ram 1500 (TSB 18-071-24) and 2023 Wagoneer/Grand Wagoneer (18-076-25) store U0405 together with U0104 as permanent codes with MIL, and the bulletins call the detection false; new PCM software lets the codes clear on their own, which matters where emissions inspections read the MIL. Expect adaptive cruise to drop out while driving is otherwise normal. U0104 is lost contact, U0305 a software conflict.
U0405 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.3 to 2 hours
- Clears after repairAfter a drive cycle
Symptoms of U0405
- Adaptive cruise control unavailable
- Check engine light that does not go out after clearing
Common causes of U0405
- Most likelyEngine controller software detecting the fault falsely (update available)
- PossibleRadar or cruise module sending implausible requests, for example after misalignment or damage
- Less likelyDisturbed CAN traffic from connectors or wiring
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Cruise control moduleCAN bus wiring
What each part of U0405 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 05 | The exact fault in that area. |
What to do next
- Note U0405 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 U0405
What does U0405 mean?
U0405 means "Invalid Data Received From Cruise Control Module". Today the module behind this code is usually the distance radar of adaptive cruise, the unit that asks the engine controller for speed and torque changes. It is a generic code, so it means the same on every make.
Is it safe to drive with U0405?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will U0405 fail an emissions test?
Yes, it can. U0405 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is U0405 to fix?
Difficulty: medium. A typical repair takes 0.3 to 2 hours of work. This is a job for a workshop.
Will U0405 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.