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 » P0233

Code P0233

Symptoms

• Engine may not start

• Engine stalls or hesitates

• Check Engine Light is on

Common Causes

• Faulty fuel pump relay

• Damaged wiring or connectors in the fuel pump circuit

• Faulty ECM

Glossary

ECM: Engine Control Module

Relay: An electrical switch that opens and closes under the control of another electrical circuit

Related Codes

• P0230

• P0231

Official description

Fuel Pump Secondary Circuit Intermittent

Laymans terms

This code means there's a problem with the electrical circuit that controls the fuel pump. It's like a light switch that sometimes works and sometimes doesn't, causing the car to not get fuel properly.

Explanation

The P0233 code is triggered when the engine control module (ECM) detects an intermittent issue in the secondary circuit of the fuel pump. This can affect the fuel delivery to the engine.

Technical description

The fuel pump secondary circuit is responsible for delivering power to the fuel pump. An intermittent issue means that the circuit is not consistently providing power, which can lead to fuel delivery problems. This can be caused by faulty wiring, connectors, or a failing fuel pump relay.

Diagnosis steps

• Check for any other diagnostic trouble codes

• Inspect the fuel pump relay and related wiring

• Test the fuel pump circuit for intermittent power loss

Repair procedures

• Replace the fuel pump relay if faulty

• Repair or replace damaged wiring or connectors

• Replace the ECM if necessary

Tools required

• OBD-II scanner

• Multimeter

• Basic hand tools

Estimated repair cost

$100 - $500

Difficulty level

Moderate

Commonly affected vehicles

• Ford F-150

• Chevrolet Silverado

• Toyota Camry

Preventive measures

• Regularly inspect and maintain electrical connections

• Replace fuel pump relay as part of routine maintenance

• Ensure ECM software is up to date

Error code type

Engine Performance

User experience recommendations

• Have the vehicle inspected by a professional if the Check Engine Light is on

• Avoid driving the vehicle if it stalls frequently

• Keep a record of any repairs related to the fuel system

Warranty information

Check vehicle warranty for coverage on fuel system components.

Historical data

This code has been associated with vehicles experiencing intermittent fuel delivery issues due to electrical faults.

Urgency level

Moderate – It should be addressed soon to avoid potential stalling or starting issues.

Legal and safety notice

Driving with a faulty fuel pump circuit can lead to unexpected stalling, which may be dangerous.

Testing conditions

• Engine running

• Vehicle in motion

Component location

The fuel pump relay is usually located in the engine bay fuse box.

FAQs

Q: Can I drive with a P0233 code?
A: It's not recommended to drive with this code as it can cause stalling and leave you stranded.

Q: How do I reset the Check Engine Light after fixing the issue?
A: Use an OBD-II scanner to clear the code after repairs are completed.

Last updated: Jan 16, 2026 • Source: internal database

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