Engine ECU Diagnostic Trouble Codes

Engine ECU - SAE Controlled

These items are taken from the table "Engine Diagnostics, SAE controlled" on pages DI-14 to DI-16 in the Engine Diagnostics chapter of the Repair Manual.

P0100 - Mass Air Flow Circuit Malfunction
P0101 - Mass Air Flow Circuit Range/Performance Problem
P0110 - Intake Air Temp Circuit Malfunction
P0115 - Engine Coolant Temp. Circuit Malfunction
P0116 - Engine Coolant Temp. Circuit Range/Performance Problem
P0120 - Throttle/Pedal Position Sensor/Switch "A" Circuit Malfunction
P0121 - Throttle/Pedal Position Sensor/Switch "A" Circuit Range/Performance Problem
P0125 - Insufficient Coolant Temp. for Closed Loop Fuel Control
P0128 - Thermostat Malfunction
P0130 - Heated Oxygen Sensor Circuit Malfunction (Bank 1 Sensor 1) (Except Calif.)
P0133 - Oxygen Sensor Circuit Slow Response (Bank 1 Sensor 1)
P0135 - Oxygen Sensor Circuit Malfunction (Bank 1 Sensor 1)
P0136 - Oxygen Sensor Circuit Malfunction (Bank 1 Sensor 2)
P0141 - Oxygen Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
P0171 - System too Lean (Fuel Trim)
P0172 - System too Rich (Fuel Trim)
P0300 - Random/Multiple Cylinder Misfire Detected
P0301 - Cylinder 1 Misfire Detected
P0302 - Cylinder 2 Misfire Detected
P0303 - Cylinder 3 Misfire Detected
P0304 - Cylinder 4 Misfire Detected
P0325 - Knock Sensor 1 Circuit Malfunction (Bank 1)
P0335 - Crankshaft Position Sensor "A" Circuit Malfunction
P0340 - Camshaft Position Sensor Circuit Malfunction
P0420 - Catalyst System Efficiency Below Threshold (Bank 1)
P0440 - Evaporative Emission Control System Malfunction

This and the following two DTCs can occur if you drive around for a while with a loose fuel filler cap.  I did this to test retreiving DTCs with the Prius Mini-Scanner and it took more than a day for the problem to be detected.

P0441 - Evaporative Emission Control System Incorrect Purge Flow
P0446 - Evaporative Emission Control System Vent Control Malfunction
P0450 - Evaporative Emission Control System Pressure Sensor Malfunction
P0451 - Evaporative Emission Control System Pressure Sensor Range/Performance
P0500 - Vehicle Speed Sensor Malfunction
P0505 - Idle Control System Malfunction

Engine ECU - Manufacturer Controlled

These items are taken from the table "Engine Diagnostics, manufacturer controlled" on pages DI-17 and DI-18 in the Engine Diagnostics chapter of the Repair Manual.

P1125 - Throttle Control Motor Circuit Malfunction
P1127 - ETCS Actuator Power Source Circuit Malfunction
P1128 - Throttle Control Motor Lock Malfunction
P1129 - Electric Throttle Control System Malfunction
P1300 - Igniter Circuit Malfunction (No. 1)
P1305 - Igniter Circuit Malfunction (No. 2)
P1310 - Igniter Circuit Malfunction (No. 3)
P1315 - Igniter Circuit Malfunction (No. 4)
P1346 - VVT Sensor/Camshaft Position Sensor Circuit Range/Performance Problem (Bank 1)
P1349 - VVT System Malfunction (Bank 1)
P1430 - Vacuum Sensor for Adsorber and Catalyst System Circuit Malfunction
P1431 - Vacuum Sensor for Adsorber and Catalyst System Circuit Range/Performance Problem
P1436 - Variable Valve Malfunction
P1437 - Vacuum Line Malfunction
P1455 - Vapor Reducing Fuel Tank System Leak Detected (Small Leak)
P1525 - Resolver Circuit Malfunction
P1600 - ECM BATT Malfunction
P1633 - ECU Malfunction (ETCS Circuit)
P1636 - HV ECU Malfunction
P1637 - EGSTP Signal Malfunction
P1656 - OCV Circuit Malfunction (for VVT-i)
P3190 - Poor Engine Power
P3191 - Engine does not start

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Last edited December 4, 2003.  All material Copyright 2003 Graham Davies.  No liability accepted.