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 » P1548

Code P1548

Symptoms

• Rough idle

• Engine stalling

• Check Engine Light illuminated

Common Causes

• Faulty idle air control valve

• Vacuum leaks

• Dirty throttle body

Glossary

Idle Air Control Valve: A component that regulates the engine's idle speed.

Throttle Body: A component that controls the amount of air entering the engine.

Related Codes

• P0505

• P0506

Official description

Idle Air Control System RPM Lower Than Expected (Bank 2)

Laymans terms

The car's computer thinks the engine is running too slow when it's supposed to be idling smoothly.

Explanation

This code indicates that the idle air control system is not maintaining the expected RPM level for the engine's idle state on Bank 2.

Technical description

The P1548 code is triggered when the powertrain control module (PCM) detects that the idle air control (IAC) system is unable to maintain the desired engine RPM during idle conditions on Bank 2. This can be due to a malfunction in the IAC valve or related components.

Diagnosis steps

• Check for vacuum leaks.

• Inspect the idle air control valve for proper operation.

• Clean the throttle body.

Repair procedures

• Replace the idle air control valve if faulty.

• Repair any vacuum leaks.

• Clean or replace the throttle body as necessary.

Tools required

• OBD-II scanner

• Vacuum gauge

• Throttle body cleaner

Estimated repair cost

$150 - $400

Difficulty level

Moderate

Commonly affected vehicles

• Toyota Camry

• Honda Accord

• Ford F-150

Preventive measures

• Regularly clean the throttle body.

• Perform routine maintenance checks.

• Inspect for vacuum leaks periodically.

Error code type

Engine Performance

User experience recommendations

• If the car stalls frequently, get it checked soon.

• Keep up with regular maintenance to prevent this issue.

Warranty information

Check your vehicle's warranty for coverage on engine components.

Historical data

This code has been associated with vehicles that have high mileage or lack regular maintenance.

Urgency level

Moderate – Should be addressed soon to prevent stalling issues.

Legal and safety notice

Driving with this issue may lead to unsafe conditions such as stalling in traffic.

Testing conditions

• Engine at operating temperature

• Vehicle in idle state

Component location

The idle air control valve is typically located on or near the throttle body of the engine.

FAQs

Q: Can I drive with a P1548 code?
A: It's possible, but not recommended. The vehicle may stall, creating unsafe driving conditions.

Q: How can I prevent this code from appearing?
A: Regular maintenance such as cleaning the throttle body and checking for vacuum leaks can help prevent this issue.

Last updated: Oct 7, 2025 • Source: internal database

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