Got The P0171 Blues in your Toyota Corolla?

Do you drive a Toyota Corolla, and currently have a check engine light? You've had the car scanned for trouble codes (DTC's), and you pull up a P0171 - System Too Lean (Bank 1) . What does this mean? What to do?

"Too lean" means that the engine is not receiving enough fuel for the amount of air coming into the engine. In other words, the engine is receiving more than 14 parts of air for 1 part of fuel. (Internal combustion engines run best at this air/fuel ratio.) While there can be numerous causes for this code to be set, on 2005 - 2008 Toyota Corollas, the repair is usually quite simple. 99% of the time, I have found the cause of a P0171 for 2005-2008 Toyota Corollas with 1ZZ-FE engines to be the intake gaskets. The problem is so common, Toyota even put out a technical service bulletin for it. For a mechanically inclined person, doing this repair can save a couple hundred dollars because the cost of the part to fix this issue is usually not more than $10.

The problem with the Corollas is that the old intake gaskets on the Corollas with the 1ZZ-FE engines is that over time, they harden and lose their elasticity. This allows unmetered air to sneak past the gasket and into the intake manifold, thereby causing a lean condition. Here's how to fix the problem.

First let's take a look at what you seen when you first open the hood.

Remove the plastic engine cover, and remove the intake tube from the air cleaner housing to the throttle body, and you've got this:

Next, remove the two 10mm bolts and two 10mm nuts holding the throttle body onto the intake manifold. Seperate the throttle body from the intake manifold, but you do not need to take the throttle body completely off the car. Just set it to the side with the coolant hoses still attached to it.

Now remove all the bolts holding the manifold to the engine cylinder head. Once you have all the bolts removed, you shouldn't have to fight it out, the manifold should easily pull right out. If it doesn't pull up off the engine easily, you probably haven't removed all the bolts. Here's how the engine bay looks with the manifold removed.

The intake manifold gasket is a one piece rubber gasket. If it is still a factory installed gasket, the gasket will be black. Go ahead and pull the old gasket off.

The new & improved intake manifold replacement gasket is orange. Install it onto the intake.

Once you have installed the new intake manifold gasket, you are ready to install the intake back onto the car. Once you have installed the intake back onto the car, start the engine and spray some carbueretor cleaner around where the intake manifold is. If there is still a vacuum leak present, the engine will idle down. If there is no vacuum leak, the engine rpm will not change as you spray carb cleaner around the intake. Of all the Corollas I have put intake gaskets on, only one required further attention after replacing the gasket. Oh, and don't forget to clear the DTC with your scan tool so the check engine light will turn off.

Most customers at our shop pay $170 - $200 (primarily for diagnosis and labor) for this easy repair on Corollas. If you're mechanically inclined, try to replace the intake gasket yourself, and you just may save a couple hundred Dollars.

How to Change Transmission Fluid in 2005+ Toyota Trucks and SUV's With World Standard ATF

For quite some time, I never knew how to service an automatic transmission for newer model Toyotas.  This was because I could never find a transmission fill tube or dipstick.  It turns out that I was not crazy or blind, there is actually NO dipstick or fill tube on 2005+ Toyota pickups and SUV's using World Standard ATF.  Here's how to change the World Standard ATF if you wish to perform the procedure yourself. 

First, you will need to make sure you've got the right tools.  Tools needed:

1. Scan tool to monitor transmission fluid temperature
2. 15/16" wrench to remove and install transmission fill plug
3. 5mm Allen socket to remove overflow plug.
4. 14 mm socket to remove transmission fluid drain plug
5. 3/8" ratchet

Once you've got all the tools together, you'll need to hook up your scan tool and verify that the ATF fluid temperature is below 115 degrees Fahrenheit.  If the fluid temperature is too high, you will need to let the truck sit for a while till the fluid temperature cools down.  This is very important.  If the fluid temperature is not correct, you may end up with an incorrect fluid level after performing a fluid drain and refill. 

Here's a screenshot from the scan tool indicating ATF fluid temperature. 

This transmission has two different temperature readings, and both indicate that the temperature is well below the 115 degree threshold, so it is safe to proceed. The next step is to either hoist the vehicle into the air, using either a lift or onto jackstands. Once the vehicle is in the air, you will be able to access the transmission fill plug. The fill plug is located on the transmission extension housing. Remove the plug with a 15/16" wrench.

Next, you will need to drain the transmission fluid. Use a 14mm socket and 3/8" ratchet to loosen the ATF drain plug. Remove the drain plug and allow the fluid to drain into a container. Go ahead and also remove the transmission overflow plug using a 5mm allen socket and 3/8" ratchet. The fill plug and the overflow plug are labeled in the below picture. In case you forget, the 14mm plug is the drain plug, and the allen plug is for the overflow tube.

Once the fluid has been drained out, you're going to need a pump to put some new World Standard ATF into your transmission. I use a pump that looks like this one below:

Replace the washer on the drain plug and reinstall the drain plug back into the transmission. Make sure that you don't over tighten the drain plug, as it will easily strip the threads in the transmission pan. Once you have the drain plug in place, use your pump to pump fluid into the transmission. You will be pumping transmission fluid where the fill plug was. I usually set the pump on a roll-around cart so I can comfortably pump the fluid until fluid begins to flow out of the overflow tube. Once you see fluid coming out of the overflow tube, temporarily install the overflow plug.

Next, start the engine and allow the transmission fluid to warm up. If it's a cold day outside, this might take a few minutes. The repair manual says you can check fluid level between 97 degrees and 115 degrees Fahrenheit. I like to check the fluid level near the upper end of this range, as this is what I have had the best luck with. I will monitor the fluid temperature with the scan tool till it reaches between 105 and 115 degrees.

Now, comes the most crucial step in the entire process. Once the transmission is at operating temperature, will the engine still running, remove the overflow plug, and either one of two things will happen. Either, transmission fluid will flow out of the overflow tube, or nothing at all will come out. If no fluid comes out of the overflow tube, the fluid level in the transmission is low, and you will need to add more fluid. Add fluid until you see fluid begin to trickle, not pour out of the overflow tube. If the fluid is gushing out of the overflow tube, the transmission is overfilled. Below is a picture of what the fluid should look like when trickling out of the transmission.

Once you're sure that the fluid level is correct, install and tighten the overflow tube plug. Lower the vehicle from the hoist or jackstands. Now, test drive the vehicle and check to make sure that the transmission shifts correctly.