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Diagnostic Codes List

This page provides a structured reference list of automotive Diagnostic Trouble Codes (DTCs) used by modern vehicle onboard diagnostic systems.

Diagnostic codes are generated by the ECU when a fault is detected in the engine, transmission, emissions system, vehicle network, or other electronic control systems. Each code represents a specific fault condition and serves as the starting point for vehicle diagnostics and troubleshooting.

This Diagnostic Codes List allows technicians and automotive professionals to browse fault codes by system category, quickly identify code meanings, and access detailed diagnostic information for each individual code.

By selecting a specific diagnostic code, you can view in-depth explanations including fault descriptions, affected systems, common causes, diagnostic procedures, and recommended inspection steps based on real-world diagnostic scenarios.

This list is designed to support efficient fault identification and accurate diagnosis using professional diagnostic tools, live data analysis, and vehicle-specific diagnostic workflows.

Select by System

P0101

Diagnostic trouble code P0101 indicates that the mass air flow (MAF) sensor signal is outside the expected range or does not match engine operating conditions calculated by the ECM

P0102

Diagnostic trouble code P0102 indicates that the mass air flow (MAF) sensor signal is lower than the minimum expected value detected by the ECM

P0103

Diagnostic trouble code P0103 indicates that the mass air flow (MAF) sensor signal is higher than the normal operating range expected by the ECM

P0104

Diagnostic trouble code P0104 indicates an intermittent or erratic signal from the mass air flow (MAF) sensor circuit

P0105

Diagnostic trouble code P0105 indicates a malfunction in the manifold absolute pressure (MAP) or barometric pressure sensor circuit detected by the ECM

P0106

Diagnostic trouble code P0106 indicates that the manifold absolute pressure (MAP) sensor signal is outside the expected range or does not correlate with engine operating conditions calculated by the ECM

P0107

Diagnostic trouble code P0107 indicates that the MAP sensor signal is lower than the minimum expected voltage detected by the ECM

P0108

Diagnostic trouble code P0108 indicates that the MAP sensor signal is higher than the expected operating range detected by the ECM

P0109

Diagnostic trouble code P0109 indicates an intermittent or erratic signal from the MAP sensor circuit detected by the ECM

P0110

Diagnostic trouble code P0110 indicates a malfunction in the intake air temperature (IAT) sensor circuit detected by the ECM

P0111

Diagnostic trouble code P0111 indicates that the intake air temperature (IAT) sensor signal is outside the expected range or performance limits

P0112

Diagnostic trouble code P0112 indicates that the intake air temperature sensor signal is lower than the expected value detected by the ECM

P0113

Diagnostic trouble code P0113 indicates that the intake air temperature sensor signal is higher than the normal operating range detected by the ECM

P0114

Diagnostic trouble code P0114 indicates an intermittent or erratic signal from the intake air temperature (IAT) sensor circuit

P0115

Diagnostic trouble code P0115 indicates a malfunction in the engine coolant temperature (ECT) sensor circuit detected by the ECM

P0116

Diagnostic trouble code P0116 indicates that the engine coolant temperature sensor signal is outside the expected range or performance limits

P0117

Diagnostic trouble code P0117 indicates that the engine coolant temperature sensor signal is lower than the expected value detected by the ECM

P0118

Diagnostic trouble code P0118 indicates that the engine coolant temperature sensor signal is higher than the normal operating range detected by the ECM

P0119

Diagnostic trouble code P0119 indicates an intermittent or erratic signal from the engine coolant temperature sensor circuit

P0125

Diagnostic trouble code P0125 indicates insufficient engine coolant temperature for closed-loop fuel control operation

P0126

Diagnostic trouble code P0126 indicates insufficient coolant temperature for stable engine operation detected by the ECM

P0127

Diagnostic trouble code P0127 indicates that the intake air temperature is higher than the maximum expected value detected by the ECM

P0128

Diagnostic trouble code P0128 indicates that the engine coolant temperature is below the thermostat regulating temperature for too long during operation

P0130

Diagnostic trouble code P0130 indicates a malfunction in the oxygen sensor circuit for Bank 1 Sensor 1 detected by the ECM

P0131

Diagnostic trouble code P0131 indicates that the oxygen sensor circuit voltage is lower than expected for Bank 1 Sensor 1, as detected by the ECM

P0132

Diagnostic trouble code P0132 indicates that the oxygen sensor circuit voltage is higher than expected for Bank 1 Sensor 1

P0133

Diagnostic trouble code P0133 indicates a slow response from the oxygen sensor circuit for Bank 1 Sensor 1

P0134

Diagnostic trouble code P0134 indicates no activity detected in the oxygen sensor circuit for Bank 1 Sensor 1

P0135

Diagnostic trouble code P0135 indicates a malfunction in the oxygen sensor heater circuit for Bank 1 Sensor 1

P0136

Diagnostic trouble code P0136 indicates a malfunction in the oxygen sensor circuit for Bank 1 Sensor 2

P0137

Diagnostic trouble code P0137 indicates low voltage in the oxygen sensor circuit for Bank 1 Sensor 2

P0138

Diagnostic trouble code P0138 indicates high voltage in the oxygen sensor circuit for Bank 1 Sensor 2

P0139

Diagnostic trouble code P0139 indicates a slow response from the oxygen sensor circuit for Bank 1 Sensor 2

P0140

Diagnostic trouble code P0140 indicates no activity detected in the oxygen sensor circuit for Bank 1 Sensor 2

P0141

Diagnostic trouble code P0141 indicates a malfunction in the oxygen sensor heater circuit for Bank 1 Sensor 2

P0147

Diagnostic trouble code P0147 indicates a malfunction in the oxygen sensor heater circuit for Bank 1 Sensor 3

P0150

Diagnostic trouble code P0150 indicates a malfunction in the oxygen sensor circuit for Bank 2 Sensor 1

P0151

Diagnostic trouble code P0151 indicates low voltage in the oxygen sensor circuit for Bank 2 Sensor 1

P0152

Diagnostic trouble code P0152 indicates high voltage in the oxygen sensor circuit for Bank 2 Sensor 1

P0153

Diagnostic trouble code P0153 indicates a slow response from the oxygen sensor circuit for Bank 2 Sensor 1

P0154

Diagnostic trouble code P0154 indicates no activity detected in the oxygen sensor circuit for Bank 2 Sensor 1

P0155

Diagnostic trouble code P0155 indicates a malfunction in the oxygen sensor heater circuit for Bank 2 Sensor 1

P0156

Diagnostic trouble code P0156 indicates a malfunction in the oxygen sensor circuit for Bank 2 Sensor 2

P0157

Diagnostic trouble code P0157 indicates low voltage in the oxygen sensor circuit for Bank 2 Sensor 2

P0170

Diagnostic trouble code P0170 indicates a fuel trim malfunction on Bank 1 detected by the ECM

P0171

Diagnostic trouble code P0171 indicates that the engine is running too lean on Bank 1

P0172

Diagnostic trouble code P0172 indicates that the engine is running too rich on Bank 1

P0173

Diagnostic trouble code P0173 indicates a fuel trim malfunction on Bank 2 detected by the ECM

P0174

Diagnostic trouble code P0174 indicates that the engine is running too lean on Bank 2

P0175

Diagnostic trouble code P0175 indicates that the engine is running too rich on Bank 2

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