U0408 code meaning
Invalid Data Received From Throttle Actuator Control Module
Network system Generic code U04xx codes Check engine light
What U0408 means
U0408 points to messages from the throttle actuator control module that the receiver, usually the ECM/PCM, judges invalid: implausible content, a failed checksum or counter, or a value outside its range. Most vehicles integrate throttle control in the engine controller, so a separate TAC module and therefore this code are uncommon; no manufacturer documents U0408 publicly. Ford's 2012 OBD summary illustrates the U04xx logic with U0401, which the TCM stores when ECM torque or pedal data are faulted. Because the throttle meters intake air, CARB's comprehensive component rules apply, and a MIL together with reduced power or a limp mode is likely. U0107 means lost contact, U0308 a software mismatch with the same module.
U0408 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0408
- Check engine light on
- Limp mode with reduced throttle response
- Unstable idle or stalling
Common causes of U0408
- PossibleDamaged bus wire or poor connector contact at the throttle module
- PossibleThrottle actuator control module internally faulty
- PossibleSoftware of throttle module and ECM do not match
- Less likelyLow or unstable supply voltage
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Throttle actuator control moduleEngine control moduleCAN bus wiring
What each part of U0408 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 08 | The exact fault in that area. |
What to do next
- Note U0408 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 U0408
What does U0408 mean?
U0408 means "Invalid Data Received From Throttle Actuator Control Module". U0408 points to messages from the throttle actuator control module that the receiver, usually the ECM/PCM, judges invalid: implausible content, a failed checksum or counter, or a value outside its range. It is a generic code, so it means the same on every make.
Is it safe to drive with U0408?
Drive gently and only to a workshop. With U0408 the car can go into limp mode (reduced power) to protect itself.
Will U0408 fail an emissions test?
Yes, it can. U0408 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 U0408 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. This is a job for a workshop.
Will U0408 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.