What Does U0408 Mean?
The ECM is receiving invalid or corrupted data from the Electronic Throttle Control (ETC) module over the vehicle network. This indicates a communication problem affecting throttle position and control data.
Safety Warning
May cause unexpected throttle response, reduced power, or limp mode activation. Critical safety issue requiring immediate attention.
Common Causes
40%
Faulty throttle body assembly with internal position sensor or actuator failure
25%
Damaged wiring or connectors between throttle body and ECM/network
20%
CAN bus communication fault or electromagnetic interference
10%
ECM internal fault or software issue misinterpreting throttle data
5%
Low voltage condition affecting throttle actuator control module operation
Diagnostic Steps
1
Step 1: Monitor throttle position sensor data with scan tool during throttle actuation to identify erratic readings
2
Step 2: Inspect throttle body connectors and wiring for corrosion, damage, or loose connections
3
Step 3: Check power and ground circuits to throttle body with multimeter (typically 5V reference)
4
Step 4: Perform throttle body relearn/calibration procedure per manufacturer specifications
5
Step 5: Test CAN bus signal quality with oscilloscope if available; check for voltage drops or noise
Estimated Repair Cost
$300 - $1,200
Parts + labor, varies by vehicle and location
The ECM is receiving invalid or corrupted data from the Electronic Throttle Control (ETC) module over the vehicle network. This indicates a communication problem affecting throttle position and control data.
The most common cause of U0408 (Invalid Data Received From Throttle Actuator Control Module) is: Faulty throttle body assembly with internal position sensor or actuator failure
Typical repair costs for U0408 range from $300 to $1,200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
May cause unexpected throttle response, reduced power, or limp mode activation. Critical safety issue requiring immediate attention.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U0408 to identify the root cause.
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Quick Info
Category
Network
System
Engine Throttle Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
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