What does the P000B fault code mean?
The P000B fault code, applicable to all car manufacturers, means “B Camshaft Position Slow Response (Bank 1)“.
Background Information: The camshaft controls the opening and closing of the valves. In a variable valve timing system, the electronic camshaft adjusting valve (or oil control valve, OCV) adjusts the camshaft angle by changing the oil pressure to the camshaft adjuster (mechanical type) according to instructions from the engine control module (ECM), ensuring the valves open and close at optimal times. Possible causes of the P000B fault include problems with the exhaust/right/rear camshaft adjusting valve (oil control valve), its circuitry, connectors, excessively dirty oil, or the ECU.
Symptoms of the P000B fault code may include:
- Engine malfunction light illuminated
- Increased emissions
- Poor engine performance
- Engine noise
Possible causes of this code include:
- Inadequate oil supply
- Camshaft position sensor malfunction
- Oil control valve failure
- VVT actuator failure
- Timing chain problem
- Wiring problem
- Faulty PCM
How to reset the P000B code?
Sometimes, fault codes like P000B appear after recent maintenance and may disappear on their own. To reset the code, use an OBD-II scanner and follow these steps:
Step 1: Connect the scanner to the vehicle’s diagnostic port.
Step 2: Follow the scanner’s instructions to clear the fault code.
If the P000B code reappears, this likely indicates a more persistent problem requiring further diagnosis.
How to diagnose P000B
- The diagnostic process should begin with the simplest and most common cause: engine oil. Confirm that the oil level is within the manufacturer’s specifications and visually inspect the oil for excessive dirt or sludge buildup. If the engine oil is dirty or low, changing the oil and filter is an unavoidable first step, as clean oil often resolves flow-related VVT issues.
- After confirming the oil is clean and the level is correct, the next step is to perform electrical tests on the VVT solenoid valve circuit and the solenoid valve itself using a digital multimeter. To check the coil’s integrity, disconnect the electrical connector and measure the resistance (in ohms) at the two terminals of the solenoid valve. Most solenoid valves have a voltage range between 5 and 20 ohms; readings outside the manufacturer’s specifications or an open circuit indicate an internal electrical fault in the coil.
- Test the vehicle’s wiring harness to ensure the solenoid valve receives the correct command signal. With the ignition switch on and the solenoid valve connector disconnected, use a multimeter set to DC voltage to confirm the battery voltage (approximately 12 volts) is present on one of the connector pins (power supply). The other pin is the PCM control circuit; testing this signal usually requires an oscilloscope for definitive results, but confirming the presence of power verifies the basic integrity of the circuit. The OCV should be removed for visual inspection, checking its internal screen and interfaces for metal debris or sludge, which are clear signs of flow restriction.
Repair the System and Clear P000B Codes
- The most likely repair after diagnosis is replacing the oil control valve (VVT solenoid valve) on the exhaust side of Bank 1. Before starting, disconnect the negative battery to prevent electrical short circuits during component replacement. The solenoid valve is typically secured by one or two bolts and can be easily accessed on the valve cover or timing cover, but its exact location varies depending on the engine.
- When installing the new solenoid valve, ensure the O-ring is lubricated with clean engine oil and ensure the component is installed correctly to maintain a seal and prevent oil pressure loss. Using genuine OEM parts or high-quality aftermarket equivalents is strongly recommended, as the valve’s precision is critical to the VVT system. After the new solenoid valve is installed and the electrical connectors are reconnected, the negative battery cable can be reconnected.
- The final step is to clear the P000B fault codes stored in the PCM memory using an OBD-II scanner. After clearing the codes, a driving cycle must be performed post-repair to allow the vehicle’s computer to reassess the VVT system’s response under different operating conditions. This process confirms that the camshaft phase occurs within the specified time, verifies the repair effect, and ensures that the fault code does not reappear immediately.
Tip: Other fault codes related to slow camshaft position actuator response include: P000A, P000C, and P000D.