How do you fix fault code P001B?

STEP 1: Inspect the connector for the Bank 1 camshaft profile solenoid. Look for oil intrusion (common leak point) or corrosion.\nSTEP 2: Perform a resistance test on the solenoid. Typical values are 10-25 Ohms (check factory specs). A reading of 0 Ohms indicates an internal short.\nSTEP 3: Check the voltage at the harness connector with ignition on. If shorted to positive, it will show battery voltage constantly even when the solenoid is commanded off.\nSTEP 4: Use an oscilloscope to monitor the PWM signal (Duty-cycle) from the ECU. If the signal is stuck 'High' despite diagnostic commands, investigate the wiring harness.\nSTEP 5: If the solenoid is confirmed faulty, replace the unit and clear the fault codes.

Powertrain (Engine & Gearbox)Standard EOBD

P001B - \

Q: What are the symptoms of fault code P001B?

• Check Engine Light (MIL) illumination\n- Noticeable loss of engine power (Limp home mode may engage)\n- Rough idling or hesitation during acceleration\n- Increased fuel consumption\n- Inspection failure due to emissions standards

Q: What causes fault code P001B?

• Most likely: Faulty Camshaft Profile Control Solenoid (internal short)\n- Likely: Wiring harness damage (short to B+)\n- Possible: Corroded or damaged connector causing high resistance or arcing\n- Rare: Internal Engine Control Unit (ECU) failure

Last updated:26 January 2026

System

Powertrain (Engine & Gearbox)

Related Fault Codes

P0000

No Diagnostic Trouble Codes (DTC) Present

P0001

Fuel Volume Regulator Control Circuit / Open

P0002

Fuel Volume Regulator Control Circuit Range/Performance

P0003

Fuel Volume Regulator Control Circuit Low

Technical Description

P001B is set when the Engine Control Unit (ECU) detects an abnormally high voltage within the 'A' Camshaft Profile Control circuit for Bank 1. This system, commonly known as Variable Valve Lift (VVL), adjusts the lift of the valves to optimize engine performance and fuel efficiency. A 'high' signal typically indicates a short to battery voltage or an open ground circuit, causing the signal to remain at a logic high level. Bank 1 identifies the cylinder bank that contains cylinder 1, and 'A' usually designates the intake camshaft lift solenoid.

Possible Causes

Faulty Camshaft Profile Control Solenoid (internal short)\n- Likely: Wiring harness damage (short to B+)\n- Possible: Corroded or damaged connector causing high resistance or arcing\n- Rare: Internal Engine Control Unit (ECU) failure

Symptoms

Check Engine Light (MIL) illumination\n- Noticeable loss of engine power (Limp home mode may engage)\n- Rough idling or hesitation during acceleration\n- Increased fuel consumption\n- Inspection failure due to emissions standards

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