P0593

Symptoms

• Cruise control completely inoperable
• Check Engine Light Illuminates
• There is no response to any button on the control unit
• Possible malfunction of adjacent steering wheel systems

Causes

• Input B signal wire short to power (+5 V or +12 V)
• Violation of the reference voltage in the resistive circuit of the buttons
• Damage to the steering wheel cable with a short to power
• ECU input stage malfunction (rare)
• Incorrect type or malfunction of the installed button block

How to Fix

1. Measure the voltage at input B with no buttons pressed (should not exceed 5 V)
2. Check signal wire for short to power
3. Inspect the steering wheel cable for damage
4. Make sure that the type and configuration of the button block matches the vehicle
5. Check the reference voltage in the button circuit
6. If the wiring is correct, check the ECU input stage

Related codes

Error P0593 by Vehicle Brand