List of all OBD Codes in your ECU

Not all OBDII codes cause an engine light, OBD codes or DTC (diagnostic trouble code) are stored by the ECU (Engine Control Unit) or PCM (Powertrain Control Module) to point the mechanic to the cause.  The engine light is an indicator of problems.  The engine light on its own does not provide details, but reading the stored DTC is a good pointer to where the issue is.

If a DTC is stored in your ECU, it doesn’t necessary mean that there will be an engine light.  In fact no other indicator may be present.  The engine light is typically reserved for drivability or emission problems.  If you’re a DIY person, you should invest in a good OBDII scanner, now available with bluetooth.

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OBD / OBDII DTC stored in the ECU (May be causing an engine light):

1. Chassis Codes (C0XXX – C3XXX)
   • C0100 – C0199: ABS and Traction Control System
   • C0200 – C0299: Steering and Suspension Codes

Chassis Codes C0100 – C0199

• C0100 – ABS Hydraulic Valve Circuit Failure
  • causes: Faulty hydraulic valves, wiring or connector, ABS control module.
• C0101 – ABS Hydraulic Valve Circuit Performance
  • causes: Faulty hydraulic valves, wiring problems, ABS control module.
• C0102 – ABS Hydraulic Valve Supply Voltage Circuit Low
  • causes: Electrical short, faulty hydraulic valves, ABS control module.
• C0103 – ABS Hydraulic Valve Supply Voltage Circuit High
  • causes: Electrical short to power, faulty hydraulic valves, ABS control module.
• C0104 – ABS Solenoid Valve Circuit Failure
  • causes: Faulty ABS solenoid, wiring or connector, ABS control module.
• C0105 – ABS Solenoid Valve Circuit Open
  • causes: Open circuit, faulty ABS solenoid, wiring or connector.
• C0106 – ABS Solenoid Valve Circuit Short to Ground
  • causes: Short circuit, faulty ABS solenoid, wiring.
• C0107 – ABS Solenoid Valve Circuit Short to Battery
  • causes: Short circuit, faulty ABS solenoid, wiring.
• C0108 – ABS Solenoid Valve Circuit Failure
  • causes: Faulty ABS solenoid, wiring or connector issues, ABS control module.
• C0109 – ABS Solenoid Valve Circuit Open
  • causes: Open circuit, faulty ABS solenoid, wiring or connector.

OBD / OBDII DTC C0110 – C0119

• C0110 – ABS Pump Motor Circuit Failure
  • causes: Faulty ABS pump motor, wiring or connector issues, ABS control module.
• C0111 – ABS Pump Motor Circuit Open
  • causes: Open circuit, faulty ABS pump motor, wiring or connector.
• C0112 – ABS Pump Motor Circuit Short to Ground
  • causes: Short circuit, faulty ABS pump motor, wiring.
• C0113 – ABS Pump Motor Circuit Short to Battery
  • causes: Short circuit, faulty ABS pump motor, wiring.
• C0114 – ABS System Relay Circuit Failure
  • causes: Faulty ABS relay, wiring or connector issues, ABS control module.
• C0115 – ABS System Relay Circuit Open
  • causes: Open circuit, faulty ABS relay, wiring or connector.
• C0116 – ABS System Relay Circuit Short to Ground
  • causes: Short circuit, faulty ABS relay, wiring.
• C0117 – ABS System Relay Circuit Short to Battery
  • causes: Short circuit, faulty ABS relay, wiring.
• C0118 – ABS System Relay Contact Circuit Failure
  • causes: Faulty ABS relay, wiring or connector issues, ABS control module.
• C0119 – ABS System Relay Coil ‘Open’ Circuit
  • causes: Open circuit, faulty ABS relay, wiring or connector.

OBD / OBDII DTC C0120 – C0129

• C0120 – ABS System Relay Coil ‘Short’ Circuit To Ground
  • causes: Short circuit, faulty ABS relay, wiring.
• C0121 – Valve Relay Circuit Failure
  • causes: ABS Faulty valve relay, wiring or connector issues, ABS control module.
• C0122 – Valve Relay Circuit Malfunction
  • causes: ABS Faulty valve relay, wiring or connector.
• C0123 – Wheel Speed Sensor Circuit Open or Shorted
  • causes: Faulty wheel speed sensor, wiring or connector.
• C0124 – Wheel Speed Sensor Input Short Circuit to Battery
  • causes: Short circuit, faulty wheel speed sensor, wiring.
• C0125 – Wheel Speed Sensor Input Short Circuit to Ground
  • causes: Short circuit, faulty wheel speed sensor, wiring.
• C0126 – Low Brake Fluid Circuit Low
  • causes: Low brake fluid level, faulty brake fluid level sensor, wiring.
• C0127 – Low Brake Fluid Circuit Open/Shorted to Battery
  • causes: Faulty brake fluid level sensor, wiring or connector.
• C0128 – Low Brake Fluid Circuit Failure
  • causes: Faulty brake fluid level sensor, wiring or connector issues, ABS control module.
• C0129 – Brake Fluid Level Low/Open Circuit
  • causes: Low brake fluid level, faulty brake fluid level sensor, wiring or connector.

OBD / OBDII DTC C0130 – C0139

• C0130 – Base Brake Pressure Sensor Circuit Failure
  • Common causes: Faulty brake pressure sensor, wiring or connector issues, ABS control module.
• C0131 – Pressure Sensor Circuit Malfunction
  • Common causes: ABS Faulty pressure sensor, wiring or connector.
• C0132 – Pressure Sensor Circuit Open
  • causes: ABS Open circuit, faulty pressure sensor, wiring or connector.
• C0133 – ABS Wheel Speed Sensor Circuit Open or Shorted
  • causes: Faulty wheel speed sensor, wiring or connector.
• C0134 – ABS Wheel Speed Sensor Circuit Open or Shorted
  • causes: Same as C0133, but for a different wheel speed sensor.
• C0135 – Left Rear Wheel Speed Sensor Circuit Malfunction
  • causes: Faulty wheel speed sensor, wiring or connector.
• C0136 – Left Rear Wheel Speed Sensor Circuit Open or Shorted
  • causes: Faulty wheel speed sensor, wiring or connector.
• C0137 – Low Brake Fluid Circuit Low
  • causes: Low brake fluid level, faulty brake fluid level sensor, wiring.
• C0138 – Low Brake Fluid Circuit Open/Shorted to Battery
  • causes: Faulty brake fluid level sensor, wiring or connector.
• C0139 – Low Brake Fluid Circuit Failure
  • causes: Faulty brake fluid level sensor, wiring or connector, ABS control module.

OBD / OBDII DTC C0140 – C0149

• C0140 – Speed Wheel Sensor LR Input Circuit Failure
  • causes: Faulty wheel speed sensor, wiring or connector issues, ABS control module.
• C0141 – Speed Wheel Sensor LR Input Circuit Open
  • causes: Open circuit, faulty wheel speed sensor, wiring or connector.
• C0142 – Speed Wheel Sensor LR Input Circuit Short to Battery
  • causes: Short circuit, faulty wheel speed sensor, wiring.
• C0143 – Speed Wheel Sensor LR Input Circuit Short to Ground
  • causes: Short circuit, faulty wheel speed sensor, wiring.
• C0144 – Speed Wheel Sensor LR Circuit Open
  • causes: Open circuit, faulty wheel speed sensor, wiring or connector.
• C0145 – Speed Wheel Sensor LR Circuit Failure
  • causes: Faulty wheel speed sensor, wiring or connector issues, ABS control module.
• C0146 – Speed Wheel Sensor LR Circuit Short to Ground
  • causes: Short circuit, faulty wheel speed sensor, wiring.
• C0147 – Speed Wheel Sensor LR Circuit Short to Battery
  • causes: Short circuit, faulty wheel speed sensor, wiring.
• C0148 – Speed Wheel Sensor LR Coherency Fault
  • causes: Inconsistent readings from the wheel speed sensor, faulty sensor, wiring.
• C0149 – Hydraulic Fluid Pressure/Flow Circuit
  • causes: Hydraulic system faults, wiring or connector issues, ABS control module.

OBD / OBDII DTC C0150 – C0159

• C0150 – Right Front Wheel Speed Circuit Malfunction
  • causes: Faulty wheel speed sensor, wiring or connector issues, ABS control module.
• C0151 – Right Front Wheel Speed Circuit Range/Performance
  • causes: Faulty wheel speed sensor, wiring problems, ABS control module.
• C0152 – Right Front Wheel Speed Circuit Low Input
  • causes: Short to ground, faulty wheel speed sensor, wiring.
• C0153 – Right Front Wheel Speed Circuit High Input
  • causes: Short to power, faulty wheel speed sensor, wiring.
• C0154 – Right Front Wheel Speed Circuit Intermittent
  • causes: Intermittent electrical connections, faulty wheel speed sensor, wiring.
• C0155 – Tire Pressure Monitoring System (TPMS) Sensor Circuit
  • causes: Faulty TPMS sensor, wiring or connector issues, TPMS control module.
• C0156 – Brake Control Signal A Circuit Open
  • causes: Open circuit, wiring or connector issues, ABS control module.
• C0157 – Brake Control Signal A Circuit Low
  • causes: Short to ground, wiring or connector.
• C0158 – Brake Control Signal A Circuit High
  • causes: Short to power, wiring or connector.
• C0159 – Speed Control System Performance
  • causes: Faulty speed control components, wiring issues, vehicle speed sensor.

OBD / OBDII DTC C0160 – C0169

• C0160 – Left Rear Wheel Speed Circuit Malfunction
  • causes: Faulty wheel speed sensor, wiring or connector, ABS control module.
• C0161 – ABS Brake Switch Circuit Malfunction
  • causes: Faulty brake switch, wiring or connector, ABS control module.
• C0162 – ABS Brake Switch Circuit Open
  • causes: Open circuit, faulty brake switch, wiring or connector.
• C0163 – ABS Brake Switch Circuit Short to Battery
  • causes: Short circuit, faulty brake switch, wiring.
• C0164 – ABS Brake Switch Circuit Short to Ground
  • causes: Short circuit, faulty brake switch, wiring.
• C0165 – ABS Control Module Circuit Failure
  • causes: Faulty ABS control module, wiring or connector.
• C0166 – ABS Control Module Circuit Open
  • causes: Open circuit, faulty ABS control module, wiring or connector.
• C0167 – ABS Control Module Circuit Short to Battery
  • causes: Short circuit, faulty ABS control module, wiring.
• C0168 – ABS Control Module Circuit Short to Ground
  • causes: Short circuit, faulty ABS control module, wiring.
• C0169 – ABS Hydraulic Pressure Differential Switch Input Open Circuit
  • causes: Open circuit, faulty pressure differential switch, wiring or connector.

OBD / OBDII DTC C0170 – C0179

• C0170 – Right Front Wheel Speed Circuit Malfunction
  • causes: Faulty wheel speed sensor, wiring or connector issues, ABS control module.
• C0171 – Right Front Wheel Speed Circuit Range/Performance
  • causes: Faulty wheel speed sensor, wiring problems, ABS control module.
• C0172 – Right Front Wheel Speed Circuit Low Input
  • causes: Short to ground, faulty wheel speed sensor, wiring.
• C0173 – Right Front Wheel Speed Circuit High Input
  • causes: Short to power, faulty wheel speed sensor, wiring.
• C0174 – Right Front Wheel Speed Circuit Intermittent
  • causes: Intermittent electrical connections, faulty wheel speed sensor, wiring.
• C0175 – Left Rear Wheel Speed Circuit Malfunction
  • causes: Faulty wheel speed sensor, wiring or connector issues, ABS control module.
• C0176 – Left Rear Wheel Speed Circuit Range/Performance
  • causes: Faulty wheel speed sensor, wiring problems, ABS control module.
• C0177 – Left Rear Wheel Speed Circuit Low Input
  • causes: Short to ground, faulty wheel speed sensor, wiring.
• C0178 – Left Rear Wheel Speed Circuit High Input
  • causes: Short to power, faulty wheel speed sensor, wiring.
• C0179 – Left Rear Wheel Speed Circuit Intermittent
  • causes: Intermittent electrical connections, faulty wheel speed sensor, wiring.

OBD / OBDII DTC C0180 – C0189

• C0180 – Right Rear Wheel Speed Circuit Malfunction
  • causes: Faulty wheel speed sensor, wiring or connector, ABS control module.
• C0181 – Right Rear Wheel Speed Circuit Range/Performance
  • causes: Faulty wheel speed sensor, wiring problems, ABS control module.
• C0182 – Right Rear Wheel Speed Circuit Low Input
  • causes: Short to ground, faulty wheel speed sensor, wiring.
• C0183 – Right Rear Wheel Speed Circuit High Input
  • causes: Short to power, faulty wheel speed sensor, wiring.
• C0184 – Right Rear Wheel Speed Circuit Intermittent
  • causes: Intermittent electrical connections, faulty wheel speed sensor, wiring.
• C0185 – Tire Pressure Monitoring System (TPMS) Sensor Circuit
  • causes: Faulty TPMS sensor, wiring or connector issues, TPMS control module.
• C0186 – Lateral Acceleration Sensor Circuit Malfunction
  • causes: Faulty lateral acceleration sensor, wiring or connector.
• C0187 – Lateral Acceleration Sensor Circuit Low Input
  • causes: Short to ground, faulty lateral acceleration sensor, wiring.
• C0188 – Lateral Acceleration Sensor Circuit High Input
  • causes: Short to power, faulty lateral acceleration sensor, wiring.
• C0189 – Lateral Acceleration Sensor Circuit Intermittent
  • causes: Intermittent electrical connections, faulty lateral acceleration sensor, wiring.

OBD / OBDII DTC C0190 – C0199

• C0190 – Yaw Rate Sensor Circuit Malfunction
  • causes: Faulty yaw rate sensor, wiring or connector.
• C0191 – Yaw Rate Sensor Circuit Range/Performance
  • causes: Faulty yaw rate sensor, wiring.
• C0192 – Yaw Rate Sensor Circuit Low Input
  • causes: Short to ground, faulty yaw rate sensor, wiring.
• C0193 – Yaw Rate Sensor Circuit High Input
  • causes: Short to power, faulty yaw rate sensor, wiring.
• C0194 – Yaw Rate Sensor Circuit Intermittent
  • causes: Intermittent electrical connections, faulty yaw rate sensor, wiring.
• C0195 – Yaw Rate Sensor Malfunction
  • causes: Faulty yaw rate sensor, wiring or connector.
• C0196 – Yaw Rate Sensor Circuit Open
  • causes: Open circuit, faulty yaw rate sensor, wiring or connector.
• C0197 – Yaw Rate Sensor Signal Fault
  • causes: Faulty signal from the yaw rate sensor, wiring or connector.
• C0198 – Yaw Rate Sensor Supply Voltage Circuit Open
  • causes: Open circuit, wiring or connector issues, power supply.
• C0199 – Yaw Rate Sensor Power Circuit Malfunction
  • causes: Power circuit, faulty yaw rate sensor, wiring or connector.

Why is my Engine Light on?

On-Board Diagnostic (OBD / OBDII) codes are stored within the Engine Control Unit (ECU) or Powertrain Control Module (PCM). These modules store the codes, monitor and control engine performance and emissions. When the system detects a fault or irregularity, it generates a diagnostic trouble code (DTC), which is stored in the ECU/PCM’s memory. This code can be retrieved using an OBD scanner, providing insights into issues.

What Are These Codes in my ECU?

On-Board Diagnostic (OBD or OBDII ) codes are part of a vehicle’s self-diagnostic system.  The ECU and sensors work together to produce DTCs, sometimes resulting in an engine light.  The codes generated do not always cause an engine light.  The development of OBD systems began in the 1980s, driven by increasing environmental concerns and regulations, especially in California. The California Air Resources Board (CARB) played a key role in this, mandating the first OBD systems.  OBD, introduced in the 1980s, was the first system of its kind.  The evolution of OBD technology culminated in the universal OBDII standard in the mid-1990s.  It provided basic capabilities to monitor and diagnose vehicle functions, primarily for emissions control.  OBDII, introduced in the mid-1990s, is a more advanced and standardized system.  This OBDII advanced system was mandatory for all cars sold in the United States from 1996 onwards.  OBDII offers broader diagnostics, real-time data, and standardization across most vehicles.  This made it easier to diagnose and address issues.  OBDII’s standardized diagnostic trouble codes (DTC) and connector types are much better than the earlier OBD system, making it easier to diagnosis and repair.