P2781 Fault Code

Downshift Switch Circuit High

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

The Downshift Switch Circuit High fault code indicates that there is a problem in the downshift switch circuit within the vehicle's transmission system. This code is commonly associated with automatic transmissions and can affect the vehicle's ability to downshift properly, impacting performance and drivability.

What are the symptoms of the P2781 code?

Symptoms of a Downshift Switch Circuit High issue can include:

• Delayed or harsh downshifts when attempting to accelerate or decelerate.
• Inability to downshift at all during driving conditions.
• Transmission slipping or erratic shifting behavior.
• Warning lights illuminated on the dashboard, particularly the check engine light.

What causes the P2781 code?

The most common causes for this fault code include:

• A faulty downshift switch, which may be stuck or malfunctioning.
• Issues with the wiring or connections related to the downshift switch, such as corrosion or frayed wires.
• A blown fuse in the circuit connected to the downshift switch.
• Problems within the transmission control module (TCM) that affect downshift operations.

How to fix P2781?

To resolve the Downshift Switch Circuit High code, the following steps can be taken:

• Inspect and test the downshift switch for proper operation and replace it if defective.
• Check the wiring and connectors for any signs of damage or corrosion, and repair or replace as necessary.
• Examine related fuses and replace any that are blown.
• Use a diagnostic scanner to reset the fault code after repairs and test drive the vehicle to ensure the issue is resolved.
• If problems persist, further diagnostics may be needed to assess the transmission control module.