What Does P0804 Mean?
The 1-4 Upshift (Skip Shift) Lamp Control Circuit has malfunctioned. This indicator lamp on the instrument cluster alerts the driver when the skip shift system is requesting a 1st-to-4th gear change for fuel economy. The PCM has detected a fault in the circuit controlling this indicator lamp, which may be an open, short, or lamp driver issue.
Common Causes
30%
Burned out skip shift indicator bulb or failed LED
25%
Open wiring in the skip shift lamp circuit
20%
Instrument cluster internal circuit failure
15%
PCM lamp driver output circuit fault
10%
Corroded ground connection for instrument cluster
Diagnostic Steps
1
Perform an instrument cluster self-test (key on, watch for all indicator illumination) to verify the skip shift lamp is capable of lighting up.
2
Back-probe the lamp circuit at the instrument cluster connector and check for PCM command voltage when skip shift conditions are met.
3
Measure continuity of the lamp circuit wire from the PCM to the instrument cluster using the wiring diagram.
4
Check for proper ground at the instrument cluster connector — a poor ground can affect multiple indicators.
5
If the bulb/LED is accessible, test it directly with a 12V source or replace it to rule out a simple bulb failure.
Estimated Repair Cost
$20 - $200
Parts + labor, varies by vehicle and location
The 1-4 Upshift (Skip Shift) Lamp Control Circuit has malfunctioned. This indicator lamp on the instrument cluster alerts the driver when the skip shift system is requesting a 1st-to-4th gear change for fuel economy. The PCM has detected a fault in the circuit controlling this indicator lamp, which ...
The most common cause of P0804 (1-4 Upshift (Skip Shift) Lamp Control Circuit Malfunction) is: Burned out skip shift indicator bulb or failed LED
Typical repair costs for P0804 range from $20 to $200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Completely safe to drive. This is purely an indicator lamp issue. The skip shift function itself may still operate normally — you just will not see the dashboard prompt to shift from 1st to 4th.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0804 to identify the root cause.
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Quick Info
Category
Powertrain
System
Transmission Control System / Instrument Cluster
Difficulty
Type
Generic (SAE)
Recommended Tools
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