Engine-CodesGeneric – P2778

P2778 Code - Upshift Switch Circuit Intermittent/Erratic

Quick Answer

The P2778 diagnostic trouble code (DTC) refers to the Upshift Switch Circuit being intermittent or erratic. Common causes include Faulty upshift switch, Damaged wiring or connectors in the circuit, Corrosion in the electrical connections. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P2778 indicates Upshift Switch Circuit Intermittent/Erratic.
Common causes
Common causes include Faulty upshift switch, Damaged wiring or connectors in the circuit, Corrosion in the electrical connections.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Table of contents Created and updated by William Orellana on Sep 18, 2024
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Code P2778 Description

The P2778 diagnostic trouble code (DTC) refers to the Upshift Switch Circuit being intermittent or erratic. This code is typically found in vehicles with automatic transmissions. The upshift switch is a component that signals the transmission control module (TCM) when to shift to a higher gear. When this circuit is experiencing issues, it can lead to erratic shifting behavior, causing the vehicle to shift gears at the wrong times or not shift at all.

OBDII Code P2778 - Upshift Switch Circuit Intermittent/Erratic
P2778 Code - Upshift Switch Circuit Intermittent/Erratic

Common Causes of P2778

  1. Faulty upshift switch
  2. Damaged wiring or connectors in the circuit
  3. Corrosion in the electrical connections
  4. Issues with the transmission control module (TCM)
  5. Software issues in the TCM

Symptoms of P2778

  1. Erratic shifting behavior
  2. Delayed or harsh shifting
  3. Transmission slipping
  4. Check Engine Light illuminated
  5. Reduced fuel efficiency

How to Fix P2778

  1. Diagnose the specific cause of the issue using a scan tool to read the DTC and perform a visual inspection of the upshift switch and related components.
  2. Test the upshift switch for proper functionality and replace if necessary.
  3. Check the wiring and connectors for any damage or corrosion, repairing or replacing as needed.
  4. Clear the DTC and perform a test drive to ensure the issue has been resolved.
  5. If the problem persists, further diagnostics may be required to identify any underlying issues with the TCM or transmission system.

Cost to Fix P2778

The cost of repairing a P2778 code can vary depending on the specific cause of the issue and the labor rates in your area. In general, the repair costs for this type of issue can range from $100 to $500, including parts and labor. It's important to note that diagnostic time and labor rates at auto repair shops can vary, so it's recommended to obtain quotes from multiple shops to get a more accurate estimate.

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Code P2778 Information for Specific Makes

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

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