While this article goes to the 2001-2005 Toyota Rav4 models, it also applies to other Toyota models and to Rav4 models of other years of manufacture too.
In the 2001-2005 Toyota Rav4 models, the most common problem is the known malfunction of the ECM (manufactured by Fujitsu Ten), that causes erratic issues to the automatic transmission of these vehicles. When this happens, the ECM must be serviced the soonest possible to avoid internal damage to the automatic transmission (you may find our professional ECM repair service in this link -> Rav4 ECM Repair Service.
The second most common problem we have found in the 2001-2005 Rav4 models we have worked with, is a sudden engine failure that could be intermittent or could fail in a steady way. Such failure is caused by cylinder misfires and most of the times it happens because of failing ignition coils. In many of those cases, more than one coil fail at the same time.
As you probably know, the Rav4 models, like many other modern models, use one independent ignition coil on each cylinder. In this case of the 2001-2005 Rav4, there are 4 ignition coils in total (2.0L and 2.4L engine).
If you experience cylinder misfirings, it probably is a failing coil or coils and the only way to accurately know which coil or coils is/are failing is by running a trouble codes scan. It can be done with any handheld generic scanner. It does not have to be expensive or any special model. If the scan results show any of the codes for cylinder misfiring, then such information will tell you exactly what cylinders are failing. Each coil has an integrated feedback circuit that tells the ECM when any of the respective coils fail to fire.
You probably have seen videos where people look for the failing coil by taking out one coil at a time while the engine is running. The ignition coil that makes no changes to the engine behavior when it is taken out, that is, if the problem does not get worse when it is taken out, it would definitely be the damaged coil. The problems of doing it that way are;
- There is a risk of electric shock.
- You may cause problems or damage electronic equipment, like the ECM, by disconnecting electric parts with the engine running.
- If there are more than one coil failing, the engine may shut off before getting to the problem, making it more difficult and confusing. Remember that for each coil you take out, you are shutting off that cylinder and you only have 4 cylinders in these 2001-2005 models.
It is up to you, but I would do it the safe way.
NOTE: You may replace the faulty ignition coil or coils and it will probably solve the problem, but remember that the unreplaced coils will have the same mileage as the damaged coil(s) had and might fail anytime soon too. Our recommendation is to ALWAYS replace all four coils.
In general, codes for cylinder misfires will tell you the cylinder(s) affected. Any code or combination of codes from the list below will guide you to the culprit:
Problems in CYLINDER #1 if any of the following is detected:
Problems in CYLINDER #2 if any of the following is detected:
Problems in CYLINDER #3 if any of the following is detected:
Problems in CYLINDER #4 if any of the following is detected:
Problems with ignition at an undetermined cylinder(s):
P0300 – Random misfire detected
NOTE: The ignition coil #1 is the one away from the battery and ignition coil #4 is the one nearest to the battery. So looking at the engine from the front, ignition coil #1 is the one at the left.
REPLACING THE IGNITION COILS
Replacing your 2001-2005 Rav4’s ignition coils is easy and you can do it yourself. You will need a 10mm socket wrench with an extension to remove the top plastic cover of the engine (2 bolts) and also for removing the coils that are going to be replaced. Each coil is attached with two 10mm bolts. Don’t let the top plastic cover scare you. After you remove the two bolts attaching it, you will just need to pull it up and it will go off.
The following are the genuine parts numbers for ignition coils of the 2001-2005 Toyota Rav4 (2.0L, 1AZ-FE engine or 2.4L, 2AZ-FE engine). Also, the same part numbers are used in the 4-Cylinder versions of the 2006-2008 Rav4 (with 2.4L, 2AZ-FE engine). All these numbers are interchangeable:
IGNITION COIL REPLACEMENTS
This is the most important part of this document. As soon as you diagnose a failing coil or coils, next you will probably be online or locally, shopping around for the best prices for replacement ignition coils. Of course, we all like to get the best quality at the best prices and that is perfectly OK, in this case, as long as you look for the OEM (genuine) ignition coils made by Denso. The MSRP (Manufacturer Suggested Retail Price) of EACH coil is over $100.00 as shown below, but that is only that, the MSRP. You may find genuine coils at online marketplaces like eBay or Amazon at a much better price. You just need to shop around.
All replacement (Non-OEM) ignition coil types that we have tried so far in a couple of years, specifically the Chinese replacements, have failed after some months, some failed in just hours of use and some others, failed almost instantly. We did on-bench tests to some of those replacement coils and it delivered high voltage for the spark, but just for seconds before dying completely. Also, the high voltage generated by these coils wasn’t near as high as the voltage that the genuine parts generate. So I can say that while the coils lasted, efficiency was way lower than expected. A spark with a lower voltage than needed will also cause misfirings in your engine just like the failing coils were doing or will cause incomplete combustion, which results in decreased engine power, lower fuel economy and will be richer in toxic emissions.
These parts are not just ignition coils. The assembly is composed of the ignition coil itself, the amplifier circuit, and the coil feedback circuit, all embedded in a solid part. The drive voltage and current are very specific and it is generated by the ECM (Engine Control Module). So a replacement ignition coil must not only have the same specific coil specifications (inductance), but the internal circuits must also match the electrical working specifications of the genuine coils.
So how to know which ignition coils to buy when all sellers put “OEM” or “Genuine” in everything they sell today?
As mentioned above, over the internet you will find online stores that will sell genuine parts for reasonable prices. You just need to know how to recognize the genuine parts out of the replica. You can never be 100% certain of something just by its looks, but this may help when you are searching. Real genuine OEM ignition coils will always have “Toyota”, “Denso” or both names in a flat surface of the assembly. The letters and numbers will be NEATLY engraved and not just painted, nor printed and not only slightly engraved. The picture below is how the genuine part looks.
NON-Genuine parts most of the time will be completely blank (no numbers, no name) and some will have only the part number engraved, no trademark or anything else. Also, color tone (dark gray or not-so-dark gray) says nothing about the part being genuine or not, as the OEM manufacturer may use different materials with slightly different colors when manufacturing a new lot. Below are some classic examples of replicas, but there are many more:
Below is an example of the yellow generic ignition coils sold for Toyota and other cars. Some are as generic as having no print at all and some others are called “High Output” or some other name that would suggest superior performance. Please just stay away from those too. Most of the times, they are the same Chinese coils, just painted in yellow.
Avoid these ignition coils on Toyota cars
NOTE: No matter how good an ignition coil looks in a picture, if the coil is marked as “Used” or “Rebuilt” or “Refurbished” as I commonly see some sellers doing on eBay, DO NOT buy it. Buying used coils is like buying a disposable battery with only half of its charge or less. It may work or it may not. If it works, you will have no idea of how long will it last until it fails, as you don’t know how much of its lifespan is left. Again, the same as disposable batteries.
If the story is something like “they are almost new, but the car was wrecked soon after I replaced them” or something like that, you may take the chance if it is at a rock-bottom price so you won’t lose much if the coils fail, but do a physical inspection of the coils first. Look for the engraved symbols and look for wear or cracks.
As for the “Rebuilt” or “Refurbished” ignition coils, who rebuild or refurbish an ignition coil??? To do that it must be taken apart and the internals repaired. These coils are sealed. They just call “rebuilding” or “refurbishing” to cleaning and/or painting. I have also seen “tested for quality before shipping“. The only way to test quality is installing it in a current vehicle and using it for some time. Bench tests will only tell about functionality, if they really do such “tests”. Quality means (1) the correct voltage, (2) it won’t misfire and (3) will last years.
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