Lost Communication With Ignition Switch Module
The U0194 code means the vehicle's onboard diagnostic system has detected: Lost Communication With Ignition Switch Module. This is a critical severity code.
- Keep driving?
- No -- stop driving
- DIY difficulty
- hard
- Estimated cost
- $200 - $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
- Vehicle will not start or turn off unexpectedly
- Key stuck in ignition
- Push-button start not responding
- Ignition position not recognized by ECM
- Multiple system faults due to lost ignition signal
Probable Causes (Ranked by Likelihood)
- Failed ignition switch or module Very High
- Damaged wiring at the ignition switch High
- Worn ignition cylinder causing intermittent contact Moderate
- Faulty push-button start switch Moderate
Step-by-Step Diagnostic Procedure
-
Check for power at the ignition switch connector in different key positions
-
Inspect the ignition switch wiring harness for damage
-
Test the push-button start switch continuity
-
Check for related immobilizer or security codes
-
Verify the brake pedal position switch (required for push-button start)
Frequently Asked Questions
Can I drive with code U0194?
No, the vehicle typically will not start or may shut off unexpectedly. This is a safety concern and requires immediate repair.
What causes U0194?
Most commonly a failed ignition switch module. On push-button start vehicles, the start button or brake pedal position switch may be the cause.
Is U0194 expensive to fix?
Costs range from $200 to $800. Ignition switch replacement on column-shift vehicles is more labor intensive. Push-button switch replacement is simpler.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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