Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

2003 Toyota MR2 C65MFACTORY OEM SERVICE PROCEDURE

Diagnostic Trouble Code Definitions

DIAGNOSTIC TROUBLE CODE DEFINITIONS

DTC ⁽¹⁾

Description

Camshaft Position "A" Actuator Circuit (Bank 1)

Camshaft Position "A" Timing Over Advanced Or System Performance (Bank 1)

Camshaft Position "A" Timing Over Retarded (Bank 1)

Crankshaft Position/Camshaft Position Correlation (Bank 1, Sensor "A")

Oxygen Sensor Heater Control Circuit Low (B1, S1)

Oxygen Sensor Heater Control Circuit High (B1, S1)

Oxygen Sensor Heater Control Circuit Low (B1, S2)

Oxygen Sensor Heater Control Circuit High (B1, S2)

Oxygen Sensor Heater Control Circuit High (B2, S1)

Oxygen Sensor Heater Control Circuit High (B2, S1)

P0100 ⁽⁴⁾

Mass Airflow Meter Circuit

Mass Airflow Meter Circuit Range/Performance

P0110 ⁽⁴⁾

Intake Air Temperature Sensor Circuit

P0115 ⁽⁴⁾

Engine Coolant Temperature Sensor Circuit

Engine Coolant Temperature Sensor Circuit Range/Performance

P0120 ⁽⁴⁾

Throttle Position Sensor/Switch "A" Circuit (M/T)

P0120 ⁽⁴⁾

Throttle/Pedal Position Sensor/Switch "A" Circuit (Sequential M/T)

Throttle/Pedal Position Sensor Circuit Range/Performance

Coolant Thermostat Malfunction

Heated Oxygen Sensor Circuit (Bank 1 Sensor 1)

Heated Oxygen Sensor Circuit Slow Response (Bank 1 Sensor 1)

Oxygen Sensor Circuit No Activity (Bank 1 Sensor 1)

Heated Oxygen Sensor Circuit (Bank 1 Sensor 2)

Heated Oxygen Sensor Circuit (Bank 2 Sensor 1)

Heated Oxygen Sensor Circuit Slow Response (Bank 2 Sensor 1)

Oxygen Sensor Circuit No Activity (Bank 2 Sensor 1)

System Too Lean (Bank 1)

System Too Rich (Bank 1)

System Too Lean (Bank 2)

System Too Rich (Bank 2)

Random Misfire Detected

Cylinder No. 1 Misfire Detected

Cylinder No. 2 Misfire Detected

Cylinder No. 3 Misfire Detected

Cylinder No. 4 Misfire Detected

P0325 ⁽⁴⁾

Knock Sensor Circuit

Crankshaft Position Sensor Circuit

Camshaft Position Sensor Circuit

Catalyst System Efficiency Below Threshold

Incorrect EVAP Purge Flow

EVAP Leak Detected (Small Leak)

EVAP Vent Control Circuit

EVAP Pressure Sensor Circuit

EVAP Pressure Sensor Range/Performance

EVAP Leak Detected (Very Small Leak)

Vehicle Speed Sensor Circuit

Brake Switch "A"/"B" Correlation⁽⁶⁾⁽⁷⁾

P0505 ⁽⁵⁾⁽⁶⁾

Idle Air Control System Circuit

P0505 ⁽⁶⁾⁽⁷⁾

Idle Air Control System Circuit

P0511 ⁽⁵⁾⁽⁶⁾

Idle Air Control System Circuit

System Voltage

Brake Switch "A" Circuit ⁽⁶⁾⁽⁷⁾

P0604 ⁽⁶⁾⁽⁷⁾

Internal Control Module RAM Error

P0606 ⁽⁶⁾⁽⁷⁾

Engine Control Module Processor

P0607 ⁽⁶⁾⁽⁷⁾

Control Module Performance

Starter Relay Circuit High

P0657 ⁽⁶⁾⁽⁷⁾

Actuator Supply Voltage Circuit Open

P0724 ⁽⁶⁾⁽⁷⁾

Brake Switch "B" Circuit High

P1126 ⁽⁶⁾⁽⁷⁾

Magnetic Clutch Circuit

Multiplex Communication Malfunction

P1646 ⁽⁶⁾⁽⁷⁾

Transmission Control ECU Malfunction

P2102 ⁽⁶⁾⁽⁷⁾

Throttle Actuator Control Motor Circuit Low

P2103 ⁽⁶⁾⁽⁷⁾

Throttle Actuator Control Motor Circuit High

P2111 ⁽⁶⁾⁽⁷⁾

Throttle Actuator Control System-Stuck Open

P2118 ⁽⁶⁾⁽⁷⁾

Throttle Actuator Control Motor Current Range/Performance

P2119 ⁽⁶⁾⁽⁷⁾

Throttle Actuator Control Throttle Body Range/Performance

P2120 ⁽⁶⁾⁽⁷⁾

Throttle/Pedal Position Sensor/Switch "D" Circuit

P2121 ⁽⁶⁾⁽⁷⁾

Accelerator Pedal Position Sensor Range/Performance

U0001 ⁽⁶⁾⁽⁷⁾

Transmission Control ECU Malfunction

⁽¹⁾	Some DTCs are two-trip detection logic DTCs. For more information, see TWO-TRIP DETECTION LOGIC under SELF-DIAGNOSTIC SYSTEM.

⁽²⁾	DTC applies to models equipped with engine immobilizer system. MIL will not illuminate if DTC exists. For testing procedures, see appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.

⁽³⁾	MIL will not illuminate.

⁽⁴⁾	If this DTC is set, Engine Control Module (ECM) will enter fail-safe mode.

⁽⁵⁾	DTC applies only to models with standard type manual transaxle.

⁽⁶⁾

There are 2 types of manual transaxles used. A standard type manual transaxle and a sequential manual transaxle. Standard type manual transaxle is a common transaxle in which the driver operates the clutch and shifts the transaxle. Sequential manual transaxle is an electronically controlled manual transaxle in which the clutch is operated and transaxle is shifted hydraulically by moving the shift lever forward or backward. Sequential manual transaxle may be identified by shift lever pattern which consists of "R", "N", "S" and "+" in place of the conventional type shift lever pattern and no clutch pedal is used.

⁽⁷⁾	Applies to models with sequential manual transaxle.

Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.

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