OBD2 (OBD-II) Codes library

• Identify the Code: Use an OBD2 scanner to read the code from your vehicle. It usually appears as a series of letters and numbers, like P0420 or B0120.

• Search for the Code: Find the code within our library to get detailed information about the issue.

• Understand the Code: Each code in our library comes with an explanation of what it means, the potential causes, and recommended fixes. This helps you decide whether it's a minor issue you can handle yourself or something that needs a professional mechanic's attention.

P0010 - Camshaft Position Actuator Circuit (Bank 1)

Description:

The camshaft position actuator circuit controls the timing of the camshaft in the engine, ensuring smooth operation.

Symptoms:

• Poor engine performance
• Check Engine Light on
• Rough idling or stalling

Possible Causes:

• Faulty camshaft position actuator
• Oil flow issues in the engine
• Faulty wiring or connectors

How to Fix:

• Replace the camshaft position actuator
• Repair or replace faulty wiring
• Perform an engine oil change

How to Prevent:

• Regular oil changes
• Routine maintenance checks

Cost to Diagnose:

SGD 80 - 150

P0171 - System Too Lean (Bank 1)

Description:

This error indicates that the fuel-to-air mixture in the engine is too lean, meaning too much air and not enough fuel.

Symptoms:

• Engine misfires
• Poor fuel economy
• Loss of power

Possible Causes:

• Faulty mass air flow sensor
• Vacuum leaks
• Dirty fuel injectors

How to Fix:

• Replace the mass air flow sensor
• Seal any vacuum leaks
• Clean or replace fuel injectors

How to Prevent:

• Regularly clean the air intake system
• Ensure fuel injectors are serviced

Cost to Diagnose:

SGD 80 - 120

P0300 - Random/Multiple Cylinder Misfire Detected

Description:

This error occurs when multiple engine cylinders are misfiring, reducing engine performance.

Symptoms:

• Rough engine idle
• Difficulty accelerating
• Engine stalling

Possible Causes:

• Faulty spark plugs
• Ignition coil issues
• Fuel delivery problems

How to Fix:

• Replace spark plugs and ignition coils
• Check fuel injectors and fuel pressure

How to Prevent:

• Replace spark plugs at recommended intervals
• Regular maintenance of the fuel system

Cost to Diagnose:

SGD 100 - 150

P0420 - Catalyst System Efficiency Below Threshold (Bank 1)

Description:

The catalytic converter is not working efficiently, which can lead to higher emissions.

Symptoms:

• Poor fuel economy
• Failed emissions test
• Check Engine Light on

Possible Causes:

• Faulty catalytic converter
• Damaged oxygen sensor
• Exhaust leak

How to Fix:

• Replace the catalytic converter
• Check and replace oxygen sensors
• Repair exhaust leaks

How to Prevent:

• Use high-quality fuel
• Maintain a regular engine service schedule

Cost to Diagnose:

SGD 150 - 250

P0500 - Vehicle Speed Sensor Malfunction

Description:

The vehicle speed sensor (VSS) provides information about the speed of the vehicle, which helps with engine and transmission control.

Symptoms:

• Speedometer not working
• Poor transmission shifting
• ABS warning light

Possible Causes:

• Faulty vehicle speed sensor
• Damaged wiring or connectors
• Faulty ABS sensor

How to Fix:

• Replace the speed sensor
• Repair or replace faulty wiring

How to Prevent:

• Regular inspection of the vehicle’s electrical system
• Routine maintenance

Cost to Diagnose:

SGD 80 - 150

P0700 - Transmission Control System Malfunction

Description:

This code indicates a problem with the transmission control system, which affects shifting and overall transmission function.

Symptoms:

• Poor or erratic shifting
• Transmission stuck in one gear
• Check Engine Light on

Possible Causes:

• Faulty transmission control module
• Wiring issues
• Transmission fluid problems

How to Fix:

• Replace or reprogram the transmission control module
• Repair damaged wiring
• Replace or top-up transmission fluid

How to Prevent:

• Regular transmission service
• Keep transmission fluid at proper levels

Cost to Diagnose:

SGD 150 - 300

P1101 - Mass Air Flow Sensor Out of Self-Test Range

Description:

The mass air flow (MAF) sensor measures the amount of air entering the engine to ensure the proper air-fuel ratio. This error occurs when the MAF sensor is out of its normal range.

Symptoms:

• Rough idling
• Reduced fuel economy
• Engine hesitation

Possible Causes:

• Dirty or faulty MAF sensor
• Air intake leaks
• Wiring issues

How to Fix:

• Clean or replace the MAF sensor
• Repair any leaks in the air intake system

How to Prevent:

• Regularly clean the air filter and MAF sensor
• Use quality fuel

Cost to Diagnose:

SGD 80 - 150

P1450 - Unable to Bleed Up Fuel Tank Vacuum

Description:

This code indicates a problem in the fuel system where the fuel tank cannot maintain proper vacuum pressure.

Symptoms:

• Difficulty filling fuel
• Check Engine Light on

Possible Causes:

• Faulty fuel tank pressure sensor
• Blocked or damaged fuel vent valve
• Fuel tank leaks

How to Fix:

• Replace the fuel vent valve
• Check for and repair any leaks in the fuel system

How to Prevent:

• Avoid overfilling the fuel tank
• Regular fuel system inspections

Cost to Diagnose:

SGD 100 - 180

P2119 - Throttle Actuator Control Throttle Body Range/Performance

Description:

The throttle actuator controls airflow to the engine. This code indicates a problem with the throttle body range or performance.

Symptoms:

• Engine stalling
• Throttle response issues
• Check Engine Light on

Possible Causes:

• Faulty throttle body
• Throttle position sensor failure
• Wiring issues

How to Fix:

• Replace the throttle body or position sensor
• Repair or replace damaged wiring

How to Prevent:

• Clean the throttle body regularly
• Maintain the vehicle's electrical system

Cost to Diagnose:

SGD 120 - 200

P2196 - O2 Sensor Signal Stuck Rich (Bank 1, Sensor 1)

Description:

This code indicates that the oxygen sensor is detecting a fuel mixture that is too rich (too much fuel, not enough air).

Symptoms:

• Poor fuel economy
• Engine misfires
• Failed emissions test

Possible Causes:

• Faulty oxygen sensor
• Fuel injector issues
• Engine control module problem

How to Fix:

• Replace the oxygen sensor
• Repair fuel injectors if necessary
• Check and update engine control module software

How to Prevent:

• Regularly check the oxygen sensor
• Use clean, high-quality fuel

Cost to Diagnose:

• SGD 100 - 200

P0130 - O2 Sensor Circuit Malfunction (Bank 1, Sensor 1)

Description:

This error code indicates a problem in the oxygen sensor circuit for Bank 1, Sensor 1. The oxygen sensor measures the oxygen level in the exhaust gases to maintain the right air-fuel mixture.

Symptoms:

• Check Engine Light on
• Poor fuel efficiency
• Rough idling

Possible Causes:

• Faulty oxygen sensor
• Damaged wiring or connectors
• Exhaust leaks

How to Fix:

• Replace the oxygen sensor
• Repair damaged wiring or connectors
• Seal any exhaust leaks

How to Prevent:

• Regularly inspect and maintain the exhaust system
• Use good-quality fuel

Cost to Diagnose:

SGD 80 - 150

P0299 - Turbocharger/Supercharger Underboost

Description:

This code is triggered when the turbocharger or supercharger is not providing the expected boost pressure to the engine.

Symptoms:

• Loss of power during acceleration
• Check Engine Light on
• Turbocharger noise

Possible Causes:

• Faulty turbocharger
• Leaks in the intake system
• Damaged or clogged boost control solenoid

How to Fix:

• Repair or replace the turbocharger
• Fix leaks in the intake system
• Clean or replace the boost control solenoid

How to Prevent:

• Regular turbo system maintenance
• Use high-quality oil and fuel

Cost to Diagnose:

SGD 150 - 300

P0301 - Cylinder 1 Misfire Detected

Description:

This code refers to a misfire in cylinder 1 of the engine, which can affect performance and efficiency.

Symptoms:

• Rough idle
• Poor acceleration
• Engine stalling

Possible Causes:

• Faulty spark plug in cylinder 1
• Ignition coil failure
• Fuel injector problems

How to Fix:

• Replace the spark plug or ignition coil
• Check and clean the fuel injector

How to Prevent:

• Regular spark plug maintenance
• Ensure proper engine tune-ups

Cost to Diagnose:

SGD 80 - 120

P0401 - Exhaust Gas Recirculation (EGR) Flow Insufficient

Description:

This code is related to the EGR system, which helps lower nitrogen oxide (NOx) emissions by recirculating exhaust gases back into the engine.

Symptoms:

• Check Engine Light on
• Rough idling
• Poor fuel efficiency

Possible Causes:

• Blocked EGR valve
• Faulty EGR sensor
• Carbon build-up in the intake manifold

How to Fix:

• Clean or replace the EGR valve
• Clean intake manifold carbon build-up
• Replace faulty sensors

How to Prevent:

• Regularly clean the EGR system
• Use fuel additives to reduce carbon build-up

Cost to Diagnose:

SGD 100 - 180

P0442 - Evaporative Emission Control System Leak Detected (Small Leak)

Description:

This error code occurs when the evaporative emission control (EVAP) system detects a small leak in the fuel system, which could result in fuel vapours escaping into the atmosphere.

Symptoms:

• Check Engine Light on
• Possible fuel smell around the vehicle

Possible Causes:

• Loose or faulty fuel cap
• Small leak in EVAP system hoses
• Faulty purge valve

How to Fix:

• Tighten or replace the fuel cap
• Check and replace EVAP system hoses
• Replace the purge valve if faulty

How to Prevent:

• Ensure the fuel cap is securely tightened after every fill
• Regularly check the fuel system for leaks

Cost to Diagnose:

SGD 80 - 150

P0507 - Idle Control System RPM Higher Than Expected

Description:

This code is triggered when the engine idle speed is higher than expected, indicating a problem with the idle control system.

Symptoms:

• High idle RPM
• Engine surges when idle
• Check Engine Light on

Possible Causes:

• Faulty idle air control valve
• Vacuum leak
• Dirty throttle body

How to Fix:

• Clean or replace the idle air control valve
• Check for and fix any vacuum leaks
• Clean the throttle body

How to Prevent:

• Regular throttle body cleaning
• Maintain vacuum lines during routine service

Cost to Diagnose:

SGD 100 - 180

P0705 - Transmission Range Sensor Circuit Malfunction

Description:

This code refers to a problem with the transmission range sensor, which tells the vehicle’s computer what gear the transmission is in.

Symptoms:

• Vehicle won’t start in park or neutral
• Difficulty shifting gears
• Transmission stuck in one gear

Possible Causes:

• Faulty transmission range sensor
• Damaged wiring
• Transmission control module issue

How to Fix:

• Replace the transmission range sensor
• Repair any damaged wiring
• Update or reprogram the transmission control module

How to Prevent:

• Regularly check the transmission system during service
• Keep the transmission fluid clean

Cost to Diagnose:

SGD 150 - 250

P1121 - Throttle Position Sensor Circuit Intermittent

Description:

This code indicates an issue with the throttle position sensor (TPS), which monitors the position of the throttle valve in the engine.

Symptoms:

• Hesitation during acceleration
• Engine surging
• Check Engine Light on

Possible Causes:

• Faulty throttle position sensor
• Damaged wiring or connectors
• Throttle body issues

How to Fix:

• Replace the throttle position sensor
• Check and repair any wiring problems
• Clean or replace the throttle body

How to Prevent:

• Regular throttle body cleaning and inspection
• Ensure proper sensor connections

Cost to Diagnose:

SGD 100 - 200

P1288 - Cylinder Head Temperature Sensor Out of Self-Test Range

Description:

This code indicates a malfunction with the cylinder head temperature sensor, which monitors engine temperature for optimal performance.

Symptoms:

• Overheating engine
• Poor fuel economy
• Engine misfire

Possible Causes:

• Faulty cylinder head temperature sensor
• Wiring or sensor connector issue
• Engine coolant problem

How to Fix:

• Replace the cylinder head temperature sensor
• Repair or replace any damaged wiring
• Ensure coolant levels are adequate

How to Prevent:

• Regularly check coolant levels and temperature sensors
• Ensure proper engine cooling system maintenance

Cost to Diagnose:

SGD 100 - 200

P2187 - System Too Lean at Idle (Bank 1)

Description:

This error occurs when the engine is running too lean (too much air, not enough fuel) at idle for Bank 1.

Symptoms:

• Rough idle
• Engine stalling
• Poor fuel economy

Possible Causes:

• Vacuum leak
• Faulty fuel injector
• Mass air flow sensor issue

How to Fix:

• Repair any vacuum leaks
• Clean or replace fuel injectors
• Replace the mass air flow sensor

How to Prevent:

• Routine fuel system maintenance
• Regularly inspect the intake and exhaust systems

Cost to Diagnose:

SGD 80 - 150

If you find yourself uncertain about what steps to take after identifying a diagnostic trouble code, it's highly recommended to consult a professional mechanic in Singapore. A qualified mechanic will have the experience and tools to accurately diagnose the issue and perform any necessary repairs, ensuring that your vehicle remains in top condition. Regular maintenance and prompt attention to these codes are crucial—not only do they help keep your car operating smoothly, but they also play a significant role in preventing larger, more costly problems down the line. Additionally, in Singapore's strict regulatory environment, keeping your vehicle in optimal condition helps you meet the country's emission standards and avoid substantial fines for non-compliance. Investing in timely repairs can save you money and hassle while ensuring that your car is safe, efficient, and roadworthy.