The Top 21 Diagnostic Trouble Codes (DTCs) for Toyota Corolla
Are you experiencing issues with your Toyota Corolla? Check out our list of the top 21 Diagnostic Trouble Codes (DTCs) for the Toyota Corolla and learn how to fix them. From ignition malfunctions to catalytic efficiency issues, our guide will help you diagnose and resolve common problems.
DTC P1604
Description: This DTC indicates a malfunction in the engine control module (ECM) internal communication circuit.
Cause: The cause of this DTC can be a faulty ECM or a wiring issue.
Symptoms: The symptoms of this DTC can include poor engine performance, stalling, and difficulty starting the engine.
Location of Fault: The fault is located within the engine control module.
How to Fix: To fix this DTC, the engine control module will need to be replaced or repaired, and any damaged wiring will need to be repaired or replaced.
DTC P0607
Description: This DTC indicates a malfunction in the engine control module (ECM) performance.
Cause: The cause of this DTC can be a faulty ECM or a wiring issue.
Symptoms: The symptoms of this DTC can include poor engine performance, stalling, and difficulty starting the engine.
Location of Fault: The fault is located within the engine control module.
How to Fix: To fix this DTC, the engine control module will need to be replaced or repaired, and any damaged wiring will need to be repaired or replaced.
DTC P0172
Description: This DTC indicates that the fuel system is running rich.
Cause: The cause of this DTC can be a faulty oxygen sensor, a clogged air filter, or a malfunctioning fuel injector.
Symptoms: The symptoms of this DTC can include a decrease in fuel economy, black smoke from the exhaust, and a rough idle.
Location of Fault: The fault is located within the fuel system.
How to Fix: To fix this DTC, the oxygen sensor or fuel injector will need to be replaced, and the air filter will need to be checked and replaced if necessary.
DTC B1421
Description: This DTC indicates a malfunction in the seat belt pretensioner circuit.
Cause: The cause of this DTC can be a faulty seat belt pretensioner or a wiring issue.
Symptoms: The symptoms of this DTC can include the airbag warning light coming on.
Location of Fault: The fault is located within the seat belt pretensioner circuit.
How to Fix: To fix this DTC, the seat belt pretensioner will need to be replaced or repaired, and any damaged wiring will need to be repaired or replaced.
DTC B2799
Description: This DTC indicates a malfunction in the immobilizer system.
Cause: The cause of this DTC can be a faulty key or a malfunctioning immobilizer system.
Symptoms: The symptoms of this DTC can include the engine not starting or the security light flashing.
Location of Fault: The fault is located within the immobilizer system.
How to Fix: To fix this DTC, the key or immobilizer system will need to be replaced or repaired.
DTC P0351
Description: This DTC indicates a malfunction in the ignition coil “A” primary/secondary circuit.
Cause: The cause of this DTC can be a faulty ignition coil, a faulty spark plug, or a wiring issue.
Symptoms: The symptoms of this DTC can include engine misfire, a decrease in engine performance, and the check engine light coming on.
Location of Fault: The fault is located within the ignition coil “A” primary/secondary circuit.
How to Fix: To fix this DTC, the ignition coil or spark plug will need to be replaced, and any damaged wiring will need to be repaired or replaced.
DTC P0115
Description: This DTC indicates a malfunction in the engine coolant temperature circuit.
Cause: The cause of this DTC can be a faulty engine coolant temperature sensor, a wiring issue, or a malfunctioning engine control module.
Symptoms: The symptoms of this DTC can include poor engine performance, a decrease in fuel economy, and the check engine light coming on.
Location of Fault: The fault is located within the engine coolant temperature circuit.
How to Fix: To fix this DTC, the engine coolant temperature sensor will need to be replaced, and any damaged wiring will need to be repaired or replaced.
DTC B279A
Description: This DTC indicates a malfunction in the passenger airbag ON/OFF indicator circuit.
Cause: The cause of this DTC can be a faulty airbag ON/OFF indicator, a wiring issue, or a malfunctioning airbag control module.
Symptoms: The symptoms of this DTC can include the airbag warning light coming on.
Location of Fault: The fault is located within the passenger airbag ON/OFF indicator circuit.
How to Fix: To fix this DTC, the airbag ON/OFF indicator will need to be replaced, and any damaged wiring will need to be repaired or replaced.
DTC P0420
Description: This DTC indicates a malfunction in the catalytic converter efficiency.
Cause: The cause of this DTC can be a faulty catalytic converter or a malfunctioning engine control module.
Symptoms: The symptoms of this DTC can include poor engine performance, a decrease in fuel economy, and the check engine light coming on.
Location of Fault: The fault is located within the catalytic converter.
How to Fix: To fix this DTC, the catalytic converter will need to be replaced, and any underlying issues with the engine or exhaust system will need to be addressed.
DTC P0353
Description: This DTC indicates a malfunction in the ignition coil “C” primary/secondary circuit.
Cause: The cause of this DTC can be a faulty ignition coil, a faulty spark plug, or a wiring issue.
Symptoms: The symptoms of this DTC can include an engine misfire, a decrease in engine performance, and the check engine light coming on.
Location of Fault: The fault is located within the ignition coil “C” primary/secondary circuit.
How to Fix: To fix this DTC, the ignition coil or spark plug will need to be replaced, and any damaged wiring will need to be repaired or replaced.
DTC P1315
Description: This DTC indicates a malfunction in the ignition coil “D” primary/secondary circuit.
Cause: The cause of this DTC can be a faulty ignition coil, a faulty spark plug, or a wiring issue.
Symptoms: The symptoms of this DTC can include an engine misfire, a decrease in engine performance, and the check engine light coming on.
Location of Fault: The fault is located within the ignition coil “D” primary/secondary circuit.
How to Fix: To fix this DTC, the ignition coil or spark plug will need to be replaced, and any damaged wiring will need to be repaired or replaced.
DTC P0354
Description: This DTC indicates a malfunction in the ignition coil “E” primary/secondary circuit.
Cause: The cause of this DTC can be a faulty ignition coil, a faulty spark plug, or a wiring issue.
Symptoms: The symptoms of this DTC can include engine misfire, a decrease in engine performance, and the check engine light coming on.
Location of Fault: The fault is located within the ignition coil “E” primary/secondary circuit.
How to Fix: To fix this DTC, the ignition coil or spark plug will need to be replaced, and any damaged wiring will need to be repaired or replaced.
DTC U
Description: This DTC indicates a communication fault in the vehicle communication network.
Cause: The cause of this DTC can be a faulty module or a wiring issue.
Symptoms: The symptoms of this DTC can vary, depending on which module is malfunctioning.
Location of Fault: The fault can be located in any module that communicates with the vehicle communication network.
How to Fix: To fix this DTC, the module or wiring issue causing the fault will need to be identified and repaired.
DTC 14
Description: This DTC indicates a malfunction in the ignition signal circuit.
Cause: The cause of this DTC can be a faulty ignition system component, a wiring issue, or a malfunctioning engine control module.
Symptoms: The symptoms of this DTC can include engine misfire, a decrease in engine performance, and the check engine light coming on.
Location of Fault: The fault is located within the ignition signal circuit.
How to Fix: To fix this DTC, the faulty component in the ignition system will need to be identified and replaced, and any damaged wiring will need to be repaired or replaced.
DTC 12
Description: This DTC indicates a malfunction in the throttle position sensor circuit.
Cause: The cause of this DTC can be a faulty throttle position sensor, a wiring issue, or a malfunctioning engine control module.
Symptoms: The symptoms of this DTC can include poor engine performance, stalling, and difficulty starting the engine.
Location of Fault: The fault is located within the throttle position sensor circuit.
How to Fix: To fix this DTC, the throttle position sensor will need to be replaced, and any damaged wiring will need to be repaired or replaced.
DTC 22
Description: This DTC indicates a malfunction in the coolant temperature sensor circuit.
Cause: The cause of this DTC can be a faulty engine coolant temperature sensor, a wiring issue, or a malfunctioning engine control module.
Symptoms: The symptoms of this DTC can include poor engine performance, a decrease in fuel economy, and the check engine light coming on.
Location of Fault: The fault is located within the coolant temperature sensor circuit.
How to Fix: To fix this DTC, the coolant temperature sensor will need to be replaced, and any damaged wiring will need to be repaired or replaced.
DTC 33
Description: This DTC indicates a malfunction in the air conditioning clutch relay circuit.
Cause: The cause of this DTC can be a faulty air conditioning clutch relay, a wiring issue, or a malfunctioning engine control module.
Symptoms: The symptoms of this DTC can include poor air conditioning performance, the air conditioning not working, and the check engine light coming on.
Location of Fault: The fault is located within the air conditioning clutch relay circuit.
How to Fix: To fix this DTC, the air conditioning clutch relay will need to be replaced, and any damaged wiring will need to be repaired or replaced.
DTC 42
Description: This DTC indicates a malfunction in the vehicle speed sensor circuit.
Cause: The cause of this DTC can be a faulty vehicle speed sensor, a wiring issue, or a malfunctioning engine control module.
Symptoms: The symptoms of this DTC can include speedometer inaccuracy, poor transmission shifting, and the check engine light coming on.
Location of Fault: The fault is located within the vehicle speed sensor circuit.
How to Fix: To fix this DTC, the vehicle speed sensor will need to be replaced, and any damaged wiring will need to be repaired or replaced.
DTC 51
Description: This DTC indicates a malfunction in the switch signal circuit for the neutral safety switch.
Cause: The cause of this DTC can be a faulty neutral safety switch, a wiring issue, or a malfunctioning engine control module.
Symptoms: The symptoms of this DTC can include difficulty starting the engine, the engine stalling, and the check engine light coming on.
Location of Fault: The fault is located within the neutral safety switch circuit.
How to Fix: To fix this DTC, the neutral safety switch will need to be replaced, and any damaged wiring will need to be repaired or replaced.
DTC 5
Description: This DTC indicates a malfunction in the throttle position sensor circuit.
Cause: The cause of this DTC can be a faulty throttle position sensor, a wiring issue, or a malfunctioning engine control module.
Symptoms: The symptoms of this DTC can include poor engine performance, stalling, and difficulty starting the engine.
Location of Fault: The fault is located within the throttle position sensor circuit.
How to Fix: To fix this DTC, the throttle position sensor will need to be replaced, and any damaged wiring will need to be repaired or replaced.
DTC 6
Description: This DTC indicates a malfunction in the coolant temperature circuit.
Cause: The cause of this DTC can be a faulty engine coolant temperature sensor, a wiring issue, or a malfunctioning engine control module.
Symptoms: The symptoms of this DTC can include poor engine performance, a decrease in fuel economy, and the check engine light coming on.
Location of Fault: The fault is located within the coolant temperature circuit.
How to Fix: To fix this DTC, the coolant temperature sensor will need to be replaced, and any damaged wiring will need to be repaired or replaced.
Note: The above information is provided for educational purposes only. It is recommended to consult a certified mechanic for accurate diagnosis and repair of any DTCs.
WORDS FROM ERWIN SALARDA
By understanding the most common DTCs for the Toyota Corolla, you can save time and money by diagnosing and fixing issues on your own. However, if you’re unsure about a problem or how to fix it, it’s always recommended to consult a certified mechanic.