Thread: moms car has had a check engine light since being jumped by the tow truck

Is it a VW? If so, don't worry, it is supposed to be on all the time...

Sometimes a low voltage condition (which is why she got a jump right?) will cause irregular readings through the sensors and will trigger a DTC. Put a good battery in it and clear the codes and then see if it comes back on.

The jump fried one of the fuses or spark plugs.

Let me get your mom's number.

I'll give her a good jump.

this is the guy with a net worth of 14 million dollars who retired at 25 but cant buy a $25 code reader off amazon for his moms honda accord

Originally Posted by Jasonw1178

Sometimes a low voltage condition (which is why she got a jump right?) will cause irregular readings through the sensors and will trigger a DTC. Put a good battery in it and clear the codes and then see if it comes back on.

this, you drain a coventional battery all the way to dead and bring it back, it may be shot and may never be the same.

coincidentally my moms car was also throwing codes and after buying a cheap reader so that she has one it was some pcm module that kept throwing a code of which they said battery could cause it and the battery while not dead was 4 years old and having rough starts, new battery and no more codes

Originally Posted by elterrible987

this, you drain a coventional battery all the way to dead and bring it back, it may be shot and may never be the same.

Wizzard. Yes this is true on a lead acid battery. If it has a static charge of under 11.9V, it will never recover. To find the static charge you have no loads on the battery. Open the hood, close doors, turn everything off wait about half an hour, a full hour if the vehicle has been started, and put a volt meter on it and see what it reads. You need to have a good battery before you can do anything else. It's funny how a semi-bad battery can cause so many issues in modern vehicles. Battery starts the vehicle fine, but yet causes module failure. Yeah, bad batteries cook modules. It acts like a resistance, especially if the fault is on the ground side. One peeve I have is that I go to diag a car and it has a crap battery and the customer is like "I know it needs a battery but I want ti find out the other problem is before I put one in it" and I'm like, mofo it needs a battery. Corroded terminals also have a host of problems.

Look up the Clore Automotive PL2320 20A smart charger. The tool companies such as Mac and Snap-on rebadge it as their own. You don't want to know what they are asking for it but on amazon it's under $80. It can maintain 13.8V for module reprogramming, but it's charging feature on a semi-bad battery it will do this thing where it charge, discharges it in a way that rejuvinates batteries. Honestly if you do anything to your own vehicles it's a must have.

If the battery drains all the way down, it can temporarily mess up a couple things causing the codes to throw.

The light was probably already on before it was dead

If buying a code reader is too much or going to autozone... I would just unplug the negative for a bit to clear it and see if it comes back. If it does, better do something about it

Originally Posted by FrankCostanza

gotta update the dollar figure now boyo but im keeping that private. i did buy one. its coming thursday.
even if the battery is 1 years old?

its not just the age its that it was cycled to zero. and its like a lot of things, some last longer than others. its like the cheapest thing to check. you could have them read/check it at an autozone or with a volt meter.

like the guy above is saying, so many electronics these days they are sensitive to voltage ranges and if your battery is out of range then chit can act weird and partially work. Car will start because the starter is a basic electric motor, it wont care too much if the voltage is out of spec as long as it gets enough starting current.

like i said above, actually had similar issue on my moms car throwing a check engine light and the code was for some control module for the engine/transmission. The car actually worked like normal but its telling you somethings wrong, the code said bad battery is a potential cause and new battery the code never came back since then. Battery is a simple and cheap thing to replace , you dont want to drive around with the code for 8 months then the module dies.

I got a cheaper ancel code reader for my moms car, the buttons on it seemed better quality than the cheapest brands but it was still about 30 bucks.

You have like 3 categories of readers and there a like 2 levels of reading. All manufacturers are required to support basic OBD2 functions. The basic OBD2 readers are like 25 bucks.

Then manufactures have their propriety data buses, you can get reader that is targeted for certain manufacturers for like 100-200 bucks. There was only like 1 that could read my moms mazda canbus and it was like 100 dollars, needs to use an app on your phone. That gives you more data and you can change things ect. I just wanted to read an engine code and have something simple enough I could atleast get her to plug in and walk her through the phone if a check engine light happens again.

Then you got pro level stuff that reads the propriety data buses for all the manufacturers, start like 500ish maybe for a cheap one and go into the thousands. Scotty kilmer likes to show off his all the time.