P0593 Fault Code

Cruise Control Multi-Function Input B Circuit High

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

The P0593 fault code indicates an issue with the cruise control multi-function input B circuit, specifically signaling a high voltage condition. This usually relates to the systems that manage the cruise control functions in the vehicle, which are essential for maintaining speed without pressing the accelerator pedal.

What are the symptoms of the P0593 code?

Common symptoms associated with the P0593 code can include:

• Cruise control malfunctioning or inoperable.
• Unexpected acceleration or deceleration when cruise control is engaged.
• Warning lights on the dashboard indicating cruise control issues.
• Inconsistent engine speed when cruise control is attempted.

What causes the P0593 code?

This fault can arise from several causes, including but not limited to:

• A short circuit in the wiring harness of the cruise control.
• Faulty cruise control switch or multi-function input device.
• High resistance within the circuit due to corroded connectors or damaged wiring.
• An issue with the Engine Control Module (ECM) mistakenly interpreting the input signal.

How to fix P0593?

To resolve the P0593 fault code, consider the following steps:

• Inspect and test the cruise control wiring harness for shorts or damages.
• Check the cruise control switch and associated connectors for proper operation and connections.
• Replace any faulty components, such as the cruise control switch or multi-function input device.
• If all components appear functional, perform a thorough inspection of the ECM's functionality and firmware updates, as necessary.