P0028

What does P0028 mean?

P0028 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Intake Valve Control Solenoid Circuit Range/Performance Bank 2.

This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.

Symptoms commonly associated with this code

Symptoms that drivers often report alongside this code. Not all may apply to every case:

• • Check engine light on, sometimes the only thing you'll notice at first
• • Lumpy or uneven idle, usually more obvious once the engine is up to temperature
• • Down on power and slow to pull away, like the engine is half asleep
• • Higher fuel bills than the car used to return, more noticeable on shorter runs
• • A faint ticking or rattle from the Bank 2 cylinder head, often louder on a cold start
• • Hesitation or a stumble when you put your foot down

Possible causes

Causes commonly associated with P0028, listed in approximate order of typical investigation. The actual cause on a specific vehicle can only be confirmed by professional diagnosis.

1. 1. Low or dirty engine oil. The solenoid relies on clean oil at the right pressure to do its job, and tired oil is the single most common reason this code shows up. Check this before anything else.
2. 2. A sticking or failed VVT solenoid on the Bank 2 intake side. They gum up internally and stop responding cleanly.
3. 3. Sludged or blocked oil passages feeding the cam phaser, common on engines that have missed a few oil changes. Restricted flow means the timing can't shift on demand.
4. 4. Damaged or oil-soaked wiring and connector at the solenoid. Oil creeps into the plug and corrodes the pins.
5. 5. A worn camshaft actuator (phaser) that physically can't reach the commanded position
6. 6. Stretched timing chain throwing the cam timing out, more likely on higher-mileage engines
7. 7. Faulty oil pressure switch feeding the ECU the wrong information

How mechanics typically diagnose

A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training.

1. 1. Check the oil level and condition first. Pull the dipstick, look at the colour, smell it, and confirm the level is right. Black, thin, sludgy oil will cause this on its own, and a service is the cheapest possible fix.
2. 2. Plug in and read all stored codes, not just P0028. Things like P0026, P0018 or P0019 alongside it point you towards the timing or phaser rather than just the solenoid.
3. 3. Inspect the Bank 2 intake solenoid connector and wiring for corrosion, chafing, or oil that's tracked down inside the plug. Clean it up and check it sits tight.
4. 4. Measure the solenoid resistance with a multimeter and compare against the manufacturer's spec. Out of range or open circuit means the solenoid is done.
5. 5. Remove the solenoid and look at the filter screen and sealing rings. A screen packed with sludge tells you the oil hasn't been changed often enough and the passages may be blocked too.
6. 6. If the solenoid, wiring and oil all check out, you're looking at the phaser or timing chain. That's a deeper job and usually a workshop one.

Common questions about P0028