What is an OBD2 code?

An OBD2 (On-Board Diagnostics) code is a diagnostic trouble code (DTC) generated by your vehicle's computer system when it detects a problem. These codes help identify specific issues with your vehicle's engine, transmission, emissions, or other systems.

How do I read OBD2 codes?

To read OBD2 codes, you'll need an OBD2 scanner. Plug it into your vehicle's OBD2 port (usually located under the dashboard), turn your key to the 'ON' position, and follow your scanner's instructions to retrieve the codes. Each code starts with a letter (P, B, C, or U) followed by four numbers.

What do the different types of OBD2 codes mean?

OBD2 codes are categorized by their first letter: P (Powertrain) for engine and transmission issues, B (Body) for interior systems like airbags, C (Chassis) for mechanical systems like brakes, and U (Network) for computer and module communication problems.

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Home » OBD2 Codes » P2668

Code P2668

Symptoms

• Fuel mode indicator lamp not working

• Check Engine Light illuminated

• Possible incorrect fuel mode display

Common Causes

• Faulty fuel mode indicator lamp

• Open or shorted wiring in the circuit

• Faulty ECM

Glossary

ECM: Engine Control Module

Circuit: A complete and closed path around which a circulating electric current can flow

Related Codes

• P2667

• P2669

Official description

Fuel Mode Indicator Lamp Control Circuit

Laymans terms

This code means there's a problem with the light that tells you what fuel mode your car is in. It's like a warning light on your dashboard isn't working right.

Explanation

The P2668 code indicates an issue with the circuit that controls the fuel mode indicator lamp. This lamp is responsible for showing the driver which fuel mode the vehicle is operating in.

Technical description

The P2668 code is triggered when the Engine Control Module (ECM) detects a malfunction in the circuit controlling the fuel mode indicator lamp. This could be due to a short circuit, open circuit, or a problem with the lamp itself.

Diagnosis steps

• Check the fuel mode indicator lamp for operation.

• Inspect wiring and connectors for damage or disconnection.

• Test the ECM for faults related to the circuit.

Repair procedures

• Replace the faulty fuel mode indicator lamp.

• Repair or replace damaged wiring or connectors.

• Replace the ECM if found faulty.

Tools required

• Multimeter

• OBD-II scanner

• Basic hand tools

Estimated repair cost

$100 - $500

Difficulty level

Moderate

Commonly affected vehicles

• Honda Accord

• Toyota Camry

• Ford Focus

Preventive measures

• Regularly inspect dashboard lights.

• Ensure wiring is secure and undamaged.

• Perform routine vehicle diagnostics.

Error code type

Electrical Circuit Issue

User experience recommendations

• Have a professional inspect the issue.

• Avoid ignoring dashboard warning lights.

• Regularly check vehicle diagnostics.

Warranty information

Check with your vehicle manufacturer for specific warranty coverage on electrical components.

Historical data

This code has been associated with vehicles that have complex fuel management systems, often appearing in models with alternative fuel options.

Urgency level

Moderate – While the vehicle may still operate, incorrect fuel mode indication can lead to inefficient fuel usage.

Legal and safety notice

Driving with a malfunctioning indicator lamp may lead to improper fuel management, affecting vehicle performance and emissions compliance.

Testing conditions

• Vehicle in operation mode

• Dashboard lights active

Component location

The fuel mode indicator lamp is typically located on the vehicle's dashboard.

FAQs

Q: Can I drive with the P2668 code?
A: You can drive, but it's advisable to fix it soon to ensure proper fuel mode indication.

Q: Is this code serious?
A: It's moderately serious as it affects your awareness of the vehicle's fuel mode.

Last updated: Mar 2, 2026 • Source: internal database

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