What Does U0406 Mean?
A control module has detected invalid or out-of-range data from the Fuel Injector Control Module (FICM). This code is common on diesel engines with standalone injector driver modules or gasoline engines with dedicated injection control.
Safety Warning
May cause severe drivability issues, loss of power, rough running, or no-start condition. Engine may run in limp mode with reduced performance. Should be diagnosed promptly.
Common Causes
35%
Failing fuel injector control module producing corrupted data
25%
FICM power supply issues affecting module performance
20%
CAN bus communication problems between FICM and ECM
15%
Injector feedback circuit faults providing invalid data
5%
Software incompatibility or outdated calibration
Diagnostic Steps
1
Step 1: Monitor FICM output data including injector pulse width, timing, and voltage feedback values
2
Step 2: Test FICM power supply voltage (typically 48-50V on diesel systems) and verify relay operation
3
Step 3: Inspect FICM connectors for corrosion, oil contamination, or damaged pins
4
Step 4: Check individual injector resistance values and compare to specifications
5
Step 5: Perform FICM buzz test or injector balance test to verify proper control and feedback
Estimated Repair Cost
$200 - $2,000
Parts + labor, varies by vehicle and location
A control module has detected invalid or out-of-range data from the Fuel Injector Control Module (FICM). This code is common on diesel engines with standalone injector driver modules or gasoline engines with dedicated injection control.
The most common cause of U0406 (Invalid Data Received From Fuel Injector Control Module) is: Failing fuel injector control module producing corrupted data
Typical repair costs for U0406 range from $200 to $2,000, depending on the vehicle, location, and whether you do it yourself or go to a shop.
May cause severe drivability issues, loss of power, rough running, or no-start condition. Engine may run in limp mode with reduced performance. Should be diagnosed promptly.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U0406 to identify the root cause.
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Quick Info
Category
Network
System
Fuel Injection System
Difficulty
Type
Generic (SAE)
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