What’s The Difference Between Stored And Pending Codes?
Determining the difference between stored and pending codes isn’t hard. A basic automotive knowledge is all that is needed.
For a quick answer though, the difference between stored and pending codes is simple. Stored codes are put in place from the manufacturer to signal the computer when a common fault is detected. Pending codes are codes that prep themselves when they determine a fault that engine cycle.
Pending codes can be just a quick flash with no symptoms or light. The stored codes are there for the vehicle to know which code to display in the event of a malfunction. Always get your codes read and verify common fixes here.
Pending codes are basically a preliminary investigation for your engine. To simplify, a random malfunction can occur during the current drive cycle but only happen for a split second. This will cause the malfunction to throw a “pending code”.
Typically pending codes are not to severe but you shouldn’t ignore them either.
Never assume a repair, always troubleshoot your codes with a diagnostic tool.
As an example, you might be driving down the road and you hit a bump which causes a spark plug to move or a wire. This wire could wiggle the wrong way and cause the spark plug to not get a great connection.
The end result is the car surges and miss fires for a second or two which causes a pending code. You normally won’t notice a warning indicator or light come on. This is because since it happened just once and so briefly, the computer doesn’t detect any problems and therefore displays no codes.
These are basically a “preventative maintenance” type of code. These won’t actually indicate a problem with the vehicle until it happens consecutively.
Stored codes are a little more complicated than pending codes. These codes are there either from the factory for legal purposes and safety precautions or because a malfunction has been detected.
What ends up happening is the computer detects too many faults. Once it determines the proper reasoning, it stores a code in the computer which then sets off a warning light.
The computer stores the actual malfunction symptom and displays a unique identifier code to let you know what exactly is wrong. Most of the time from vehicle to vehicle these codes might be the same across all vehicle platforms.
This would mean that all the auto manufacturers use pretty much the same “error code” for many of the same symptoms. As an example, the term P0420 usually means a catalytic converter problem. This code however is ran across many different makers like Chevy, Ford, Dodge, etc… all of these vehicles will share that same code for a catalytic problem.
Other vehicles may be that rare occasion though where the codes might be completely difference.
To sum it up short, the difference between stored and pending codes is simple. One will show you a warning light because it has detected a for sure concern. The other will only be there as a preventative measure.
Using a code reader you can actually pull both codes.
Get Rid Of Them!
Another main difference between stored and pending codes is how you get rid of them. Some codes are permanently installed in the engine’s computer just for overall safety and emission requirements.
However, you can actually “clear” or remove the stored codes that are currently causing a problem pretty easily. Fix the problem.
You should never ignore a check engine light. Is the light ugly to look at, yes it is, but it isn’t something you should completely panic about either. We have had it plenty of times where our check engine light came on. After a quick scan, turned out the gas cap wasn’t on tight enough.
So basically don’t panic if you have your warning light come on. If it starts blinking, turn over immediately as this is a critical error code. This means something went completely wrong during the operation of that engine.
If it starts blinking get towed home immediately, DO NOT RISK DRIVING IT!
You can clear codes either by fixing them or by getting them repaired by a shop and having them clear the codes. It is illegal in some areas to clear codes yourself, you have been warned.
That pretty much sums up the difference between stored and pending codes in your car. Be sure to check out some other fun car questions we have answered, you can see how long a head gasket typically lasts here.