What Does U0442 Mean?
The primary control module is receiving invalid data from a secondary Engine/Powertrain Control Module. This occurs in systems with dual PCMs or when engine data is shared across multiple processors.
Safety Warning
Engine may run in limp mode with reduced power. Vehicle may stall or have poor drivability. Not safe for highway speeds or extended driving until repaired.
Common Causes
35%
Failed secondary ECM/PCM module with internal fault
25%
Corroded or damaged connector at PCM B
20%
CAN bus wiring fault between primary and secondary PCMs
15%
Software version mismatch between PCM A and PCM B
5%
Poor ground connection at secondary PCM
Diagnostic Steps
1
Step 1: Use scan tool to identify which data parameters from PCM B are showing as invalid or out of range
2
Step 2: Inspect electrical connectors at both primary and secondary PCMs for corrosion, moisture, or damage
3
Step 3: Verify power and ground circuits at secondary PCM meet specifications (typically 12V supply, <0.1 ohm ground)
4
Step 4: Monitor CAN bus communication between PCMs using oscilloscope to verify proper signal quality
5
Step 5: Check software version compatibility between modules and reflash if updates are available
Estimated Repair Cost
$400 - $2,500
Parts + labor, varies by vehicle and location
The primary control module is receiving invalid data from a secondary Engine/Powertrain Control Module. This occurs in systems with dual PCMs or when engine data is shared across multiple processors.
The most common cause of U0442 (Invalid Data Received From ECM/PCM "B") is: Failed secondary ECM/PCM module with internal fault
Typical repair costs for U0442 range from $400 to $2,500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Engine may run in limp mode with reduced power. Vehicle may stall or have poor drivability. Not safe for highway speeds or extended driving until repaired.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U0442 to identify the root cause.
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Quick Info
Category
Network
System
Powertrain Control System
Difficulty
Type
Generic (SAE)
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