P0804 Fault Code

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

• What does that mean?
• Symptoms
• Causes
• Solutions

The P0804 fault code indicates a malfunction in the Upshift (Skip Shift) Lamp Control Circuit. This circuit is responsible for monitoring and controlling the upshift indicator which helps in optimizing fuel efficiency by prompting the driver to shift gears at the right moment.

What are the symptoms of the P0804 code?

Symptoms associated with the P0804 fault code may vary but often include:

• The upshift indicator light remaining illuminated
• Poor fuel economy due to improper shifting behavior
• Transmission may not shift at optimal points
• Driver may experience shifting difficulties or notice irregular transmission behavior.

What causes the P0804 code?

Potential causes of the P0804 fault code include:

• A faulty upshift (skip shift) switch
• Damaged wiring or connectors in the circuit
• Malfunctioning transmission control module (TCM)
• A blown fuse related to the skip shift circuit
• Miscommunication between the vehicle's onboard computer and the transmission system.

How to fix P0804?

To resolve the P0804 fault code, follow these steps:

1. Inspect the upshift switch for any damage or wear.
2. Check the wiring and connectors for continuity and signs of damage.
3. Test the transmission control module for proper operation.
4. Replace any blown fuses that are associated with the skip shift circuit.
5. Clear the fault codes and test drive the vehicle to ensure the issue is resolved.