Facing a fluid situation

I have written several articles on the importance of scheduled maintenance, such as making sure to stay up to date with fluid intervals and filters. Failure to perform these basic services and have them performed by a qualified shop can only cost you money and headaches in the long run.

Last week we had a new customer come in with his 2007 Lexus IS 250. The customer said he had just purchased the car and after driving it only 50 miles, the check engine light came on. What he did not realize is that the previous owner did not have quality maintenance performed.

After connecting the scanner, we pulled four codes:

  • P0012: Camshaft Position “A” Timing Over-Retarded (Bank 1)
  • P0014: Timing Over-Advanced or System Performance (Bank 1)
  • P0021: “A” Camshaft Position – Timing Over-Advanced or System Performance (Bank 2)
  • P0022: “A” Camshaft Position – Timing Over-Retarded (Bank 2)

These codes seemed unusual to us; it’s more common to see one valve timing code – not 4. If all four were correct, we were facing a major oiling problems or major engine damage.

But before I get too far into what we found, let me explain modern timing control. Before 1990, powertrains in most cars used a distributor; after that, most cars featured distributorless timing systems. These newer systems have three main components. There is a sensor at the crank shaft (or crankshaft position sensor) that sends a signal to the main computer (ECM, PCM or DME) that can tell the coils when to fire the spark plugs. Unlike a vacuum advance on a distributor, the distributorless ignition system could not mechanically change engine timing. So several car companies began to experiment with variable valve timing camshafts that are now standard.

If you want the engine to have a smooth acceleration with power, the valve timing must be different from idle to 4000 rpm. These variable valve timing systems use high-pressure oil to physically move the cam gear or camshaft. Once the engine control module sees the car accelerating or decelerating, it commands a pressure solenoid that enables oil to flow in and out of the variable cam gear. This cam movement, or phasing, allows the base timing to advance or retard. If you want this system to work properly, the engine’s oil level must be correct and the engine oiling system components must be functioning correctly.

DIAGNOSING THE PROBLEM

We checked the oil level and oil condition on the Lexus IS 250. The engine oil was clean and the level was OK. We checked the electrical connectors at the oil pressure solenoids and everything was in order. We then cleared the codes and drove the car.

After the second test-drive, code P0014 came back. We suggested that we remove the Bank 1 “B” solenoid for inspection and possible replacement. We also suggested an oil change, because the customer did not know the service history of the car.

When we removed the Bank 1 “B” oil pressure control solenoid, we noticed normal wear on the shaft, but because oil pressure solenoids can stick intermittently, they are difficult to diagnose. It was not until we removed the oil filter during the oil change that we found the problem. The car had the incorrect oil filter installed. The oil filter was too tall and when the last shop tightened it down, the filter crushed into the housing. Once the oil filter was distorted, the oil flow slowed down.

It is unknown how long the car ran with the incorrect oil filter or if the engine sustained other damage due to the restricted oil flow. One thing that was strange is that the engine did not exhibit any abnormal noise or sounds when the oil pressure was restricted. If it were not for the check engine light coming on for valve timing, the engine may have torn itself apart over time.

Always make sure to check your oil and only take your car to a trusted repair facilities.