Lost Communication With Alternative Fuel Control Module
What does U0108 mean?
The U0108 code means the vehicle's onboard diagnostic system has detected: Lost Communication With Alternative Fuel Control Module. This is a moderate severity code.
Common Symptoms
- Check Engine Light illuminated
- Alternative fuel system inoperative
- Vehicle defaults to gasoline only
- Reduced fuel economy
Probable Causes (Ranked by Likelihood)
- Failed alternative fuel module Very High
- CAN bus wiring issue to module High
- Corroded module connector Moderate
- Module power supply loss Low
Step-by-Step Diagnostic Procedure
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Check alternative fuel module power and ground
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Inspect module connector
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Verify CAN bus wiring
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Check alternative fuel system components
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Replace module if communication lost
Frequently Asked Questions
Can I drive with code U0108?
Drive short distances only. Lost communication codes indicate a module has stopped communicating on the vehicle network. The affected system may not function correctly.
What causes U0108?
The most common cause is a failed module or a wiring issue in the CAN bus network. Failed alternative fuel module is the most likely cause. Power supply, ground, and connector issues should be checked before replacing any module.
Is U0108 expensive to fix?
Repair costs range from $150 - $800 (parts and labor). Wiring repairs are on the lower end, while module replacement is on the higher end. The module may also need to be programmed after replacement.