P0804 low

1-4 Upshift (Skip Shift) Lamp Control Circuit Malfunction

The P0804 code means the vehicle's onboard diagnostic system has detected: 1-4 Upshift (Skip Shift) Lamp Control Circuit Malfunction. This is a low severity code.

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Keep driving?
Yes, but fix soon
DIY difficulty
easy
Estimated cost
$20 - $200 (parts and labor)
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Common Symptoms

  • Check Engine Light illuminated
  • Skip shift indicator lamp not functioning
  • Skip shift lamp stays on constantly
  • No visual indication when skip shift engages

Probable Causes (Ranked by Likelihood)

  • Burned out skip shift indicator bulb Very High
  • Open or short in lamp control circuit wiring High
  • Faulty instrument cluster connection Moderate
  • PCM driver circuit failure Low

Step-by-Step Diagnostic Procedure

  1. Check if the skip shift indicator bulb is burned out and replace if necessary

  2. Inspect wiring from the PCM to the skip shift lamp for damage

  3. Test the lamp circuit with a test light or multimeter

  4. Verify PCM output to the lamp circuit using a scan tool

Frequently Asked Questions

Is P0804 a serious problem?

No, P0804 only affects the skip shift indicator lamp. Your vehicle will drive normally and the transmission is not at risk.

Can I pass an emissions test with P0804?

P0804 will illuminate the Check Engine Light, which may cause you to fail an emissions inspection in some states. The fix is usually inexpensive.

Is the skip shift lamp the same as the shift indicator?

No, the skip shift lamp specifically indicates when the 1-4 skip shift feature is active. The standard shift indicator is a separate system.

Sources

This page is built from documented references. Verify against your own service info before repair work.

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