P05xx fault codes: Idle speed and vehicle speed control

Unstable idle, cruise control, auxiliary inputs to the control unit. These codes show up as erratic behaviour at a standstill, or a function that refuses to engage.

How to read this code

The letter P names the system: Powertrain. The next digit, 5, locates the fault: idle speed and vehicle speed control.

These codes are generic: they mean the same thing on every make. Some manufacturer tools display them with a two-digit suffix, such as P0101-00 or P010100: the suffix refines the fault type, and the base code keeps its meaning.

The codes of this family, part by part

Vehicle speed sensor

• P0500Vehicle Speed Sensor Malfunction
• P0501Vehicle Speed Sensor Range/Performance
• P0502Vehicle Speed Sensor Circuit Low Input
• P0503Vehicle Speed Sensor Intermittent/Erratic/High

Idle speed control

• P0505Idle Control System Malfunction
• P0506Idle Control System RPM lower Than Expected
• P0507Idle Control System RPM higher Than Expected

Throttle and accelerator pedal position sensors

• P0510Closed Throttle Position Switch Malfunction

Engine oil pressure sensor

• P0520Engine Oil Pressure Sensor/Switch Circuit Malfunction
• P0521Engine Oil Pressure Sensor/Switch Range/Performance
• P0522Engine Oil Pressure Sensor/Switch Low Voltage
• P0523Engine Oil Pressure Sensor/Switch High Voltage

Air-conditioning pressure sensor

• P0530A/C Refrigerant Pressure Sensor Circuit Malfunction
• P0531A/C Refrigerant Pressure Sensor Circuit Range/Performance
• P0532A/C Refrigerant Pressure Sensor Circuit Low Input
• P0533A/C Refrigerant pressure Sensor Circuit High Input
• P0534Air Conditioner Refrigerant Charge Loss

Power steering pressure sensor

• P0550Power Steering Pressure Sensor Circuit Malfunction
• P0551Power Steering Pressure Sensor Circuit Range/Performance
• P0552Power Steering Pressure Sensor Circuit Low Input
• P0553Power Steering Pressure Sensor Circuit High Input
• P0554Power Steering Pressure sensor Circuit Intermittent

System voltage

• P0560System Voltage Malfunction
• P0561System Voltage Unstable
• P0562System Voltage Low
• P0563System Voltage High

Cruise control

• P0565Cruise Control On Signal Malfunction
• P0566Cruise Control Off Signal Malfunction
• P0567Cruise Control Resume Signal Malfunction
• P0568Cruise Control Set Signal Malfunction
• P0569Cruise Control Coast Signal Malfunction
• P0570Cruise Control Accel Signal Malfunction
• P0571Cruise Control/Brake Switch A Circuit Malfunction
• P0572Cruise Control/Brake Switch A Circuit Low
• P0573Cruise Control/Brake Switch A Circuit High
• P0574through P0580 Reserved for Cruise Codes