Lost Communication With Generator Control Module
The U0175 code means the vehicle's onboard diagnostic system has detected: Lost Communication With Generator Control Module. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- moderate
- Estimated cost
- $300 - $800 (parts and labor)
Network codes mean modules are not communicating. You need a scanner that reads all systems to find the problem.
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Common Symptoms
- Battery warning light illuminated
- Charging system not functioning properly
- Battery draining while driving
- Electrical accessories dimming
- Vehicle may stall due to low voltage
Probable Causes (Ranked by Likelihood)
- Failed alternator with integrated control module Very High
- Damaged wiring between ECM and alternator High
- Corroded alternator connector Moderate
- ECM unable to communicate with smart alternator Low
Step-by-Step Diagnostic Procedure
-
Test charging voltage at the battery with engine running (should be 13.5-14.5V)
-
Check the alternator connector for corrosion or damage
-
Inspect the wiring from the ECM to the alternator
-
Verify the drive belt tension and condition
-
Use a scan tool to check alternator duty cycle and target voltage
Frequently Asked Questions
Can I drive with code U0175?
Only short distances. Without proper charging the battery will eventually drain and the vehicle will stall. Go directly to a repair shop.
What causes U0175?
Modern vehicles use smart alternators controlled by the ECM. The most common cause is a failed alternator with a built-in control module.
Is U0175 expensive to fix?
Expect $300 to $800. Smart alternator replacement is the most common repair. Wiring fixes are less expensive when applicable.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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