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 » P133B

Code P133B

Symptoms

• Check Engine Light is on

• Engine misfires

• Poor engine performance

Common Causes

• Faulty ionic current control module

• Wiring issues or short circuits

• Defective ignition coil for cylinder 9

Glossary

ECM: Engine Control Module

Ionic Current: A method used to detect misfires by measuring ionization in the combustion chamber

Related Codes

• P133A

• P133C

Laymans terms

The car's computer is having trouble with the electrical signal for one of the spark plugs in cylinder number 9. It's like trying to send a message, but the signal is too strong.

Explanation

This code indicates that the ionic current control module is detecting a high voltage condition in the control line for ignition cylinder 9.

Technical description

The P133B code is set when the Engine Control Module (ECM) detects that the ionic current control module's control line for ignition cylinder 9 is experiencing a higher than expected voltage. This could be due to a malfunction in the control module, wiring issues, or a faulty ignition coil.

Diagnosis steps

• Use an OBD-II scanner to confirm the code

• Inspect the wiring and connectors for cylinder 9

• Test the ignition coil for cylinder 9

Repair procedures

• Replace faulty wiring or connectors

• Replace the ignition coil for cylinder 9

• Replace the ionic current control module if necessary

Tools required

• OBD-II scanner

• Multimeter

• Socket set

Estimated repair cost

$150 - $500

Difficulty level

Moderate

Commonly affected vehicles

• BMW 5 Series

• BMW 7 Series

• BMW X5

Preventive measures

• Regular maintenance and inspection of ignition system

• Ensure proper installation of ignition components

• Use quality parts for replacements

Error code type

Engine Performance

User experience recommendations

• Do not ignore the Check Engine Light

• Have the vehicle inspected by a professional

• Avoid driving the vehicle if performance issues are severe

Warranty information

Check with the vehicle manufacturer for warranty coverage on ignition components.

Historical data

This code is often associated with high-performance vehicles using advanced ignition systems.

Urgency level

Moderate – Addressing this issue promptly can prevent further engine damage.

Legal and safety notice

Driving with a misfiring engine can lead to increased emissions and potential engine damage.

Testing conditions

• Engine at operating temperature

• Vehicle in a safe, stationary position

Component location

The ignition coil for cylinder 9 is located on the engine, usually on top of the cylinder head.

FAQs

Q: Can I drive my car with a P133B code?
A: It's not recommended as it can lead to further engine damage.

Q: How can I clear the P133B code?
A: After repairs, use an OBD-II scanner to clear the code.

Last updated: Jun 9, 2026 • Source: internal database

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