Check engine vs. Service engine

[Debunker]

Originally Posted by rswarrior

It's now my understanding that "Check Engine" indicates a problem, sometimes as simple as a loose gas cap. "Service Engine Soon" is used by some manufacturers (BMW comes to mind) to indicate it's time for maintenance.

And Hondas and Acuras in the late 80's had "PGM-FI" lights.

BTW in the timing chains vs. belts: my brother had a chain break on an interference engine and had major engine damage. I had a Honda timing belt break at 50K miles, with an interference engine, and everything just happened to be in the right place - no damage.

Oh, and if you have a 1996 car or later, I recommend the purchase of an OBD-II reader. That way when you CE or SES or whatever light comes on, you can read the codes from the computer, so you can avoid getting ripped off when you take it in to be fixed. In some cases, like mine, you can replace something simple and save $$$.

[blinkingblythe]

Originally Posted by TatorKate

The only time I have ever encountered a "check engine" light ended in financial disaster. Once upon a time (the time was actually 3AM), in a land free of cell phones, I looked down to see a tiny illuminated icon. By the time I had figured out what it said, the engine had died. I took the walk of shame to a pay phone. After a humiliating phone call, a morning tow, and a mechanic's visit, I was informed that my timing belt had broken. I don't know which was more shocking-the $1000 bill or the realization that there is a car part called a timing belt. For those of you with a timing chain- don't rub it in. Suffice it to say, I am now terrified of the "check engine" light/icon/whatever.



Oh and Ana- it too was a Volkswagen!

Yikes! Sounds like your car has what is known as an "interference engine" meaning that the engine has a piston that moves in and out of the same space the valves do. The timing is supposed to prevent a collision between these parts, and if the belt breaks, *bam* and an expensive repair. Non-interference engines don't have this problem when the belt breaks.

[kanazawa]

Originally Posted by Mr. Furious

Sorry for continuing my hijack, but did you know that a new condenser for a 2008 Honda Accord costs $760? I do! Know how I know? The service adviser said that it looks like some sort of road debris (rock, stick) flew up and punched a hole in it. And, of course, since that isn't a manufacturing defect, it isn't covered under warranty.

I'll shut up now, this isn't Twitter.

Condensor or compressor. Anyways, I assume that is including labor and materials?

The condensor itself lists for 307.22, but you can get it online for 221.20. Of course lots of places won't install parts you bring to them cause the lose the said markup.

http://www.hondapartscheap.com/south...t=0&quantity=0

[Casey]

Originally Posted by Debunker

And Hondas and Acuras in the late 80's had "PGM-FI" lights.

BTW in the timing chains vs. belts: my brother had a chain break on an interference engine and had major engine damage. I had a Honda timing belt break at 50K miles, with an interference engine, and everything just happened to be in the right place - no damage.

Oh, and if you have a 1996 car or later, I recommend the purchase of an OBD-II reader. That way when you CE or SES or whatever light comes on, you can read the codes from the computer, so you can avoid getting ripped off when you take it in to be fixed. In some cases, like mine, you can replace something simple and save $$$.

The earlier cars have OBD systems, too. OBD-I was in use from about 1991 to 1994, OBD-I.5 was a transitional system from late 1994 to early 1996, though most cars had either OBD-I or OBD-II, with OBD-I.5 being the notation to show that it wasn't standardized.

Love my OBD-I reader- thing has saved me a fortune through the years.

[Eddylizard]

Stupid question but is there any easy way for a muffin like me to establish whether my engine is interferance or non-interferance?

[BoKu]

Originally Posted by Eddylizard

Stupid question but is there any easy way for a muffin like me to establish whether my engine is interferance or non-interferance?

I was about to say no, but I now see that there a couple interference engine lists on the Interwebs. For example:

http://www.aa1car.com/library/timing...ce_engines.htm

http://www.gates.com/part_locator/in...o=Interference

However, I would still take all of them with a grain of salt.

Thanks, Bob "BoKu" K.

[Eddylizard]

Cheers BoKu, but the shoebox I drive isn't on the list (Tigra TT 1.8 Litre sport ECOTEC (Every Component On This Engine's Crap) engine).

[Broken Sword]

What an informative thread.

The Toyota I had just had the engine symbol - no words. It came on twice - once because I forgot the gas cap, and once because I was using a non-factory gas cap that apparently wasn't a tight enough fit.

Oh, and I put 180,000 miles on it without the timing chain giving me the slightest problem.

[Roadsterboy]

Originally Posted by Eddylizard

Cheers BoKu, but the shoebox I drive isn't on the list (Tigra TT 1.8 Litre sport ECOTEC (Every Component On This Engine's Crap) engine).

Eddy, it's my understanding that the whole ECOTEC engine family is interference. IIRC your car is fairly new, no? Unless you're putting intergalactic miles on it I would think you're safe!

I don't think I've ever seen a comprehensive list of interference/non-int. engines-such a list would be enormous! But I think that non-interference engines are in the minority-I have a vague recollection of reading an article about why interference is more common, but of course can't find any actual references to it.

-RB

[Eddylizard]

Roadsterboy yes it was built in 2008 but sat unused, unwanted and unloved in the showroom until I bought it this year (as new, 50 on the clock - needed a new battery but they threw that in). Let's be honest no-one wants this model of car - except me. That's probably why they racked down production from 200 per week in 2006 to 20 (for the entire European market) and have now stopped making them altogether. As I've posted before though it wasn't the exact specs and trim I wanted, the dealer snatched my hand off to sell it to me for half price after I worked him down a bit. Okay I'm not really going to turn down a £9 grand saving because it doesn't have an all black roof.

The advisory on the timing belt is I think 40,000 miles - in other words just outside the warranty. However if I drive eight thousand miles in a year, that means I've had a better than average year adventure wise Nearer 5,000 would be it for me. So I'm not terribly worried.

[robertplattbell]

Check Engine Lights are related to emissions controls.

In the late 1970's, the EPA mandated that emission controls be warranted for 50,000 miles. Carmakers fought this on technical and financial grounds. The key component that was problematic was the oxygen sensor (or Lamba probe, named for the 16.67:1 air to fuel ratio that provides optimal combustion).

While exhaust systems could be made to last 50,000 (up to the catalytic converter, anyway) by aluminizing them or using stainless steel, the fragile lambda probe would only last about 25,000 miles. The probe detects oxygen in the exhaust and uses rare earth elements in its construction.

The solution was to provide a light on the dashboard that would illuminate after 25,000 miles. For most cars, this was triggered by a device attached to the odometer - a simple gear driven switch. It could be reset by a unbent paper clip for another 25,000 miles. Many drivers did this, instead of replacing the oxygen sensor.

OBD I (On Board Diagnostics, version I) was introduced in the early 1990's. These systems used generally one oxygen sensor (or one per bank) ahead of the catalytic converter. When the "check engine" light was illuminated, it could be read (on some cars) using a "stomp test" where jamming the acceleration pedal to the floor with the key in the ON position would cause the light to blink in a morse-code fashion.

OBD I cars were fairly robust and not prone to generating spurious codes. But it should be noted that just because a code mentions a particular car part, does not mean the corresponding repair is to replace that part. Even experienced car mechanics often fail to see this.

Oxygen sensor technology had improved by that time to the point where the sensors were deemed good for 50,000 miles. Most manufacturers recommend replacing them at a predetermined interval, although I have found that time, as well as mileage, is indicative.

Error codes on OBD I and OBD II cars may reset over time (after a predetermined number of starts) if the underlying error is no longer present.

SRS (airbag) and ASC (traction control) lights, generally do NOT reset over time, as these are safety related items. Usually a separate code reader is required for these items. A typical problem with SRS systems occurs when seatbelt switches become momentarily disconnected, when the connectors are kicked by back seat passengers or are pulled when moving the seat from one extreme to another. Usually, cleaning the contact and wire-tying the connectors together snugly fixes the problem. Many dealers instead recommend expensive replacement of seat switches.

Bear in mind that Check Engine error codes are generally emissions related and do not necessarily mean the engine is going to fail. If your engine does fail, the Check Engine light may come on, but the reverse is not true. The CE light is not as critical as your temperature light, and particularly your OIL light. If the temp light comes on, you have minutes to shut off the engine to prevent further damage. If the oil light comes on, seconds. Most cars can run for years with an illuminated CE light, depending on what error is generating it.

To avoid panic on the part of consumers, some manufacturers experimented with different wordings, such as "check engine soon" or "service engine soon" or the like.

As previously noted by others, these should not be confused with engine service indicators for oil changes an services, such as used by BMW for its oil change interval detector (which bases oil change intervals on number of starts, speeds driven, temperatures, loads, time, etc.) or the mileage based Inspection I and Inspection II protocols.

OBD II was introduced around the mid 1990's. This newer system features on-board emissions testing, as well as diagnostics, and as a result, in many states, emissions testing consists of plugging the car into an analyzer using the OBD II port (often under the dash) and see if there are any error codes.

Note that error codes may be stored, even if the check engine light is OFF. IN many instances, the CE light will not be lit until an error code is present for a predetermined amount of time, or if a number of error codes are present. This was an attempt by the manufacturers to get OBD II to stop crying "Wolf" and it works, to some extant.

OBD II cars constantly monitor emissions by using a second oxygen sensor (or sensors, if multiple banks are used) to measure oxygen content after the catalytic converter. Similarly, the evaporative emissions system is checked by monitoring pressure in the system. It is a much more complex and error prone system than the older OBD I cars.

Most OBD II cars require a code reader in order to read out the error codes and diagnose problems. Usually a specialized code reader for a particular make will have a code book specific to that make and model car. Generic readers, often offered for free use at many auto parts stores (Autozone or the like) generate "P-codes", which are generic codes to all makes and models (and often less useful in diagnosing problems). Usually these codes are the letter P with four digits after them.

For the do-it-yourself mechanic you can often google search an error code (ANDed with the model car name) and find websites, discussion groups, blogs, and even photos, describing the likely problem and illustrating do-it-yourself repair procedures.

Again, just because an error code mentions an engine part does not mean that part is at fault. For example, "Oxygen sensor out of range" usually means that a leak has formed in an inexpensive ($15) rubber intake belows, which can be easily replaced. It generally does not mean the more expensive oxygen sensor is broken.

Similarly, a "Catalytic Converter Efficiency Below Threshold" message may indicate a faulty oxygen sensor, which is a far cheaper part than the catalytic converter. OBD II codes do not indicate the part at fault, but the symptom of the underlying problem. They are a diagnostic tool, not a "read and replace" instruction device.

Many consumers have been angered by OBD II cars, which, like a Windows-based computer, often generate spurious error codes. A loosely attached gas cap, for example, will generate a "Check Engine" light, with the code translating to "Large Leak - Evaporative Emissions System" or the like. Usually tightening the gas cap fixes the problem. A thin film of plumbers silicone grease on the gasket also helps.

Occasionally, the OBD II computer just goes beserk and "throws codes", for example, if you stall the car. These codes are not an indication of any real failure, just the computer receiving a voltage spike or inconsistent readings and generating error messages.

Just as you would not start tearing apart a Windows computer every time it generates an error message, you should not immediately go looking for broken parts on your car because the Check Engine light is on (particularly with an OBD II car). Reset the code first and see what happens.

Usually, resetting the code (again, a code reader makes this easy for the consumer to do) will clear the problem, with no need for a trip to the dealer. If a code reappears immediately, it is likely a "hard fault" and a broken part is likely indicated (e.g., camshaft positions sensor, throttle position switch, etc.).

If an error code reappears over time, then a condition may exist that needs repair. Writing down the codes and the date and monitoring them can be an effective diagnostic, just as checking your blood pressure is and effective diagnostic of your circulatory health.

For emissions testing, the computer needs 50 to 100 miles of sample data to "log" in order to determine whether the car is operating properly. Resetting the check engine light just prior to emissions testing will usually result in an immediate failure for lack of logging data. If you reset the CE light, drive the car at least 50 miles before testing, or it will fail on low data.

That's probably more than you wanted to know. In reality, the engine management computer is a fairly primitive device, compared to the computer on your desk. It is not too difficult to diagnose problems with the error codes associated with the CE light, particularly with the help available on the Internet.

Good Luck.

[robertplattbell]

Note also that the oxygen sensors on most OBD II cars are now good for 100,000 miles, although many fail based on time of use, not merely mileage.

If an oxygen sensor fails, the car may run rough (usually too rich) which could eventually cause other engine problems (in theory) or clog the catalytic converters (over time). But it usually does not mean you have to pull the car over right away.

Another one of the Rube Goldberg contraptions on some OBD II cars is the Secondary Air Pump.

Some vehicles use a primary air pump to pump air into the exhaust to help combust unburnt hydrocarbons. This was a typical emissions approach in the 1970's, resulting in very high temperatures in the exhaust manifold (sometimes called a "thermal reactor"). Most makers have moved away from using AIR pumps (AIR = Air Injection Reaction) as fuel injection is far more efficient and maintains the ideal stoichiometric ratio, resulting in less unburned hydrocarbons.

But on initial cold startups, excess hydrocarbons may be emitted. A small electric air pump may be used to pump air in to the exhaust manifold to help the catalytic converters process this excess fuel and to speed the warmup of the converter system.

The pump may look like a miniature shop vac, usually mounted on the passenger's side fenderwell. When this fails, you may get a "low flow, secondary air system" error message.

When the car is started cold, you may hear this pump running for the first minute or two. If it starts to fail, it may sound very loud (like marbles in it).

FWIW.