Engine light flash ten times?

The flashing Check Engine light means there is too much unburned fuel going into the exhaust system and you must stop the engine as soon as safely possible. To keep driving will overheat the catalytic converter, often leading to a very expensive repair.

There's two kinds of self-tests you may be thinking of. The first has been around ever since we started using Engine Computers. They look at sensor readings and engine operating conditions to detect problems, both electrical in nature and mechanical. On a vehicle as new as yours, there are thousands of things that can be detected, each with a corresponding diagnostic fault code.

A second type of self-test involves emissions system tests. These have long lists of conditions that must be met for a test to be performed. There's perhaps a half dozen of these tests, that if they pass, can be read at emissions testing stations, then no further testing is required.

Related to the Check Engine light, you can get an idea of the severity of a diagnostic fault code by how the light acts. Of the thousands of potential codes, only about half of them refer to something that could adversely affect emissions. Those are the codes that turn on the Check Engine light. Any of the other half of the codes can be set but the light will not be on.

When the defect detected could affect emissions, the Check Engine light will turn on, but if it's minor, and an intermittent problem and it goes away, the light will turn off while you're driving. If it's a little more severe, even if the problem goes away, the light will remain on until you stop, then restart the engine. The light won't turn on again for that problem until it occurs again.

When it's still more severe, even when the problem goes away at times, the Check Engine light will always be on. For the highest level of severity, as I mentioned, the light will be flashing. The defect is causing too much unburned fuel to go into the exhaust system. It burns in the catalytic converter and will melt the catalyst. Besides plugging the exhaust system and causing poor engine performance, the computer will detect the new problem and set a fault code for, "catalyst inefficiency". We shudder when we see that because we know it's going to be an expensive repair.

One point to be aware of related to these fault codes is they never, ever say to replace a part or that one is bad. The people at many auto parts stores will read fault codes for you for free, but they're in the business of selling parts. A specific sensor or other part is listed in only about half of the codes, and even with those, that part is the cause of that code only about half of the time. Way too often we read too late that someone replaced the part two or three times, yet the same fault code keeps on setting. First we check for things like broken wires, corroded connector terminals, and mechanical problems associated with that part. Only after the rest of the circuitry tests okay do we spend our customers' money on a part.

The special emissions system tests run in the background without you ever knowing. They have nothing to do with the Check Engine light. The only way to know whether they've passed, failed, or haven't run yet is to view that on a scanner. The conditions that must be met for a test to run varies greatly between car brands, models, and years. They can include such things as a brief burst of wide-open-throttle, a steady throttle that never hits idle or wide-open-throttle for at least five minutes, or for at least 20 miles, the engine must have been at normal operating temperature for a specific amount of time, etc. The list usually includes no other fault codes must be set, or there can be no other fault codes set related to the test waiting to run. When we need to have a test run that hasn't done so by the time you get to the testing station, we have to find the list of conditions for that test, then go out and drive the car and try to achieve each one of them. Often we inform the owner of the need to do that because it can involve quite a bit of time or miles.

you can get an idea of the types of things we learn from diagnostic fault codes by looking at this list:

https://www.2carpros.com/trouble_codes/obd2/p0200

These codes are reasonably common among all car brands and models, 1996 and newer. There are many more specific to each model. When you get one of those, I can look up the definition and interpret it for you. It's best to write down the exact fault code number when you have the codes read. Most scanners and code readers provide a description, but there can be discrepancies between those. With the code number, we can find the definition right from the manufacturer's list.

Have you had the fault codes read and recorded?

Then the flashing light indicates a self-test hasn't run, otherwise a code would have set. These tests are referred to as "monitors". I mentioned some of the conditions that must exist for some tests to run. Others for your model can include the fuel level must be between 1/4 and 3/4, and the engine coolant must be up to operating temperature within a certain period of time. Monitors can reset and need to be run again if the battery is disconnected.

Those monitors typically include tests of the oxygen sensors, catalytic converter efficiency, EGR system, and evaporative emissions system. That last one has to do with the charcoal canister, fumes in the gas tank, and the gas cap.

The problem with the needed conditions is they vary a lot between car models and manufacturers, so the best way to know how to get the monitors to run is to ask at the dealership. Here's the list I found for the catalytic converter efficiency monitor:

Minimum 330 seconds since start-up at 21°C (70°F)
Engine coolant temperature is between 76.6°C - 110°C (170°F - 230°F)
Intake air temperature is between -7°C - 82°C (20°F - 180°F)
Time since entering closed-loop is 30 seconds
Inferred rear HO2S temperature of 482°C (900°F)
EGR is between 1% and 12%
Part throttle, maximum rate of change is 0.2 volts/0.050 sec
Vehicle speed is between 8 and 112 km/h (5 and 70 mph)
Fuel level is greater than 15%
First Air Flow Cell
Engine RPM 1,000 to 1,300 RPM
Engine load 15 to 35%
Inferred catalyst temperature 454°C - 649°C (850°F - 1,200°F)
Number of front HO2S switches is 50
Second Air Flow Cell
Engine RPM 1,200 to 1,500 RPM
Engine load 20 to 35%
Inferred catalyst temperature 482°C - 677°C (900°F - 1,250°F )
Number of front HO2S switches is 70
Third Air Flow Cell
Engine RPM 1,300 to 1,600 RPM
Engine load 20 to 40%
Inferred catalyst temperature 510°C - 704°C (950°F - 1,300°F)
Number of front HO2S switches is 30

"Closed loop" just means once the engine is warmed up, the oxygen sensor readings get added into the list of sensor readings used to calculate fuel metering needs.

The "cells" they're talking about make up a large "lookup" table for fuel needs. One cell would include a specific vehicle speed, a specific intake air temperature, a specific throttle position, direction of change, and rate of change, and any other variable that affects how much fuel to inject. Those tables start out with default values programmed at the factory. During driving, the computer starts with those values to calculate fuel needs, then it uses the front oxygen sensor readings to fine tune those values as you drive. Those are called "short-term fuel trim", (STFT) numbers.

When the computer sees it is always making the same corrections for a cell, it makes an adjustment to the default value, then uses that new number as the starting point. Those are the "long-term fuel trim", (LTFT) numbers. That reduces how often it needs to make short-term adjustments.

If you don't get any ideas from this list of conditions, the dealer will be able to help. They often run into the same missing detail over and over.

Time is not one of the variables. Look at the list of conditions required, like spurts of wide-open-throttle, or fuel level between 1/4 and 3/4. Have you met those conditions?

Some of my formatting didn't transfer when I pasted that list. Where it says, "First Air Flow Cell", the next four items are a subset under that heading. Same with, "Second Air Flow Cell". Also, this list is for just one of the monitors. It's for "catalytic converter efficiency". This test might have already passed. There's three other monitors. There may be other conditions that need to be met for those to run.

There's huge lists of conditions that must be met. There's no point in obsessing over one or two. Often owners bring their cars to the dealer to have a mechanic do the drive cycles so they'll pass emissions tests, and even the mechanics get frustrated. You just have to wait until the tests run and pass. Also consider the tests may have already run multiple times, but one or two failed.

That agrees with everything we've discussed. One or more of the monitors haven't run or they've run and not passed. Nows it's up to the dealer to figure out why.

Laws vary in regards to emissions testing. In the past it was done by sticking an analyzer probe up the tail pipe. Today, newer models do that same testing for you so all the test station personnel need to see is those tests passed. In some jurisdictions, they will still do the old-school manual testing when the car didn't do it automatically.

There's thousands of parts, loose hose connections, leaking gaskets, corroded electrical connector terminals, and computers that can cause a failure. Part of the frustration is we don't know why a monitor hasn't run or hasn't passed. When the problem can be detected by the Engine Computer, it sets a diagnostic fault code and turns on the Check Engine light. When the Check Engine light is not on, it suggests there has been no defect detected, or the defect is not related to emissions. Now it becomes an issue of figuring out which condition(s) haven't been met for a monitor to run. When there is no fault code, it's up to the emissions system specialist to figure out why the monitors haven't passed.

Go back and look at that list of conditions again. That is for just one of the monitors, and there's at least three different sets of conditions that must be met at different times. The dealer will have the specialized equipment, and some of their specialists may know right away what it takes to solve this. Without access to their experience, choosing a cause is no better than throwing a dart at the dart board.