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SHould I replace sensors,wires or fuses?

Apparently,I need to run this by “you guys”…I’ve been getting a "check engine light for some time now (I don’t wanna say how ling) :frowning: Regardless,I was finally able to have it tested when the light was actually on (Oh,and,it seems that my cigarette lighter fuse was interfering with this also) ?? Anyway,I was told to get the map sensor fixed first (They told me that that the bank 1 sensor was shorted out.And,thet said something about “high voltage”) Now,I replaced the map sensor.But,now that I think about it,I’m thinking it’s something electrical & not ,simply the map sensor :frowning: (Which I replaced) Am I wrong ? They then said the range performance sensor was also shorted out.Now,(I guess) my real question is should I be replacing these sensors or,some wires or,possibly, some simple fuses ??? I have extremely little experience with automotive repair and I live on a VERY “limited income”.So,I would prefer to do these repairs myself (if at all possible) (I’ve found youtube to be of great help) (for the most part) :wink: I can try to give you more info if needed.But,It might take a while :frowning: Thanks for any & all help !!! I’ll check back in tomorrow (Hopefully) :frowning:

Codes posted would be the first step, they may be stored depending on the year and make of the vehicle, also considered at minimum pertinent information. Assuming map sensor is MAF sensor.

Some cars don’t have a MAF (mass airflow sensor) they have a MAP (manifold absolute sensor).

The MAP sensor can give a bad reading from the wiring but more commonly from the vacuum hose going to it, either from the moisture in the line or loss of vacuum from a cracked vacuum hose.

Speaking for myself, I am not sure I understand what all your problems are. Besides the lights, are there performance issues? What kind of car are we talking about?

You said you had the map sensor fixed. What happened after it was fixed? Still having the check engine light? What made you decide to replace the range performance sensor? What makes you think you should replace wires and fuses? Only takes 5 minutes to check ALL fuses in a car.

Out of curiosity, who is giving you all this advice, a dealer? What are the codes?

MAP sensor failure (I presume you mean MAP, not MAF) is not a common thing reported here. They’re pretty robust gadgets and live in a more pristine environment than the crank position sensor for example, which is a more common failure item reported here.

Maybe a little tutorial would help. MAP means “Manifold Absolute Pressure” and it is really just a measure of the air pressure in the intake manifold. It’s like a barometer in other words. That pressure varies by the amount of load on the engine. A idle there’s very little air pressure, but going wide open throttle up a steep hill there’s much higher air pressure in the intake manifold. The computer uses that sensor’s info to determine how much fuel to inject for the driving condition.

the first thing to check then is whether the MAP is properly connected up. There’s usually three or four wires that go to it, and there’s a thick hose that goes from the intake manifold to the MAP. If the wires and the hose look ok, ask your shop to remove the hose and check the ability of the MAP to hold vacuum using a hand-held vacuum pump. It should easily hold and maintain vacuum to -20 inch of mercury. If you still have the old sensor, try it on that one too. That’s a place to start anyway.

Range performance sensor, not sure what that is. Suggest you post the make/model/year of your vehicle.

Did the check engine light go away?

As to all this “shorted out” stuff, there’s no engine code that says “it’s shorted out.”

The engine code basically points at a part and says “Something is wrong with what I’m being told by this part.”

As an example, if you get an oxygen sensor code, it could be a bad oxygen sensor, or it could be that the oxygen sensor is working just fine and is detecting a problem, which is what it’s there to do.

Too many mechanics these days see an engine code and immediately replace whatever part the code points to without doing any actual diagnostic work to see why the code was thrown in the first place.

It sounds to me like you’ve found one of these mechanics.

Start by telling us what car we’re talking about here.

From you post, it sounds to me that the check engine light is intermittent. It does not have to be on in order to read the code. If the light goes out, the code is still stored for up to 10 drive cycles. Unless you live in California, you can get the codes read for free at most auto parts stores like AutoZone etc.

We can give you the most help if you get the codes read and post the actual code here. It will be in a format with a letter followed by 4 numbers. Engine and transmission codes start with a P like P0174. Post the actual code here along with the year, make and model of your car and any drivabiltiy symptoms here.

That points to a bad oxygen sensor. Not a bad MAP sensor.


Oldtimer_11-Haven’t actually checked into this yet.But,I wanted to thank you for that info !!

George…Thank you VERY much for this info ! I will indeed take this under advisement !

shadowfax-YOU sound liuke you know what you’re talking about…I had the codes checked at a local auto parts store.They are the ones who said “shorted out”.After I replaced The MAP (not Maf) sensor,no…the check engine light did not go off.About a week later it did go off.And,then,about 2 weeks after that it came back on again.And,then,about a week after that it’s now off again ! It’s been off now for about a week.And,for those who wanted to know…tis is a 2003 Saturn Ion !

Keith-the “check engine” light is indeed “intermittent” ! I WILL tell you though that the guys at autozone told me that that light did have to be on in order for them to check it ! ?? II was going to have it checked once and they even said somethimng about a fuse that I had that was burned out interfering with them being able to check ! ? The light is out (again).I will try to get the actual codes the next time the lioght comes on (Or,whenever I can) :frowning: :frowning: :frowning:

And,Thank you ALL VERY much for your help !!!

The guys at AutoZone are wrong, the light does not have to be on to read the code. But then, they aren’t mechanics, just salesmen.

Keith,thank you again ! That’s exxactly what I thought.And,I am BY NO MEANS “mechanically inclined”.Although,mosty of my family were and my last gf was !!