U0194 critical

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.

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Keep driving?
No -- stop driving
DIY difficulty
hard
Estimated cost
$200 - $800 (parts and labor)
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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

  1. Check for power at the ignition switch connector in different key positions

  2. Inspect the ignition switch wiring harness for damage

  3. Test the push-button start switch continuity

  4. Check for related immobilizer or security codes

  5. 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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