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Check engine light is on. What to do now?

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Old 03-21-2005, 07:33 AM
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Exclamation Check engine light is on. What to do now?

This morning i woke up to get ready to go to school and as always i start my car up. I drove to the highway everything was fine but then when going up a hill my check engine light went on. I got to school and did not have any time to pop my hood but i turned my car off and started it up again, it started fine.
What should i do now? Should i go and get dignosis or could it be a chronic problem? I mean the car has 156k, so what can i do?
Old 03-21-2005, 07:37 AM
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First things first, get the code checked to see what it is and the go from there. Most of the parts stores around where I live will check them for free so you might try to find a good local one around you.


Edit*

I just noticed your other thread about mudding last week, you may have sucked some mud or water into the filter, pull your air filter and check to make sure it's clean and that everything behind it is clean as well.

good luck, let's hope it's nothing to serious

Last edited by idotmyi; 03-21-2005 at 07:41 AM.
Old 03-21-2005, 07:57 AM
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i think it might be the dirt because some things are dusty
Old 03-21-2005, 07:59 AM
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what do you mean by cheking the code
Old 03-21-2005, 08:09 AM
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when your check engine light comes on it will grnerate a fault code telling you what it is that is causing the light to come on. In order to read the codes you need a scan tool that will plug into your OBDII plug like these http://www.jcwhitney.com/autoparts/S...=10201&sku=OBD

but as you can see they are expensive. So the alternative is to find a good parts store that will take the two minutes to plug thiers in and tell you what the problem is.
Old 03-21-2005, 09:05 AM
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Originally Posted by idotmyi
when your check engine light comes on it will grnerate a fault code telling you what it is that is causing the light to come on. In order to read the codes you need a scan tool that will plug into your OBDII plug...
Check his sig, he's running a 1990 rig which is pre-OBDII.

cccp... you can "pull the code" by shorting out a couple of pins on the "diagnostics" connector under your hood. Doing this will cause the CEL to blink a series of times that relate to the "code" or "number" of the problem. Once you have that number, you can look up the problem with a cross-reference chart.

I'll step aside and let someone else with an early model truck give you specifics on what to do.
Old 03-21-2005, 09:43 AM
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If you look by the fuse box in your engine bay on the passenger side, there is a small grey box next to it labeled "DIAGNOSTIC". Open that up and you will see a bunch of terminals. There are two terminals you need to jump to pull codes, they are "E1" and "TC". There should be a diagram with labels on the cap IIRC. Jump these with a wire or something that is conductive and watch the blinks when you have the key turned to ON (you have 4 seconds to get from the diagnostic box to the cab where you can see the CEL... Hurry!

The first series of blinks will occur every half second. The number of blinks will be the first digit in the error code. A pause of 2.5 seconds will then occur and it will blink every half second for x amount of times again. This is the second digit of the error code. For example: 4 blinks, pause, 1 blink = 41, which is low battery voltage. If there are multiple codes stored, they will be spaced out by 4 seconds. Hopefully that makes sense, I didn't proofread.

Somebody respond if I missed anything. Does anybody know a link to a list of the codes?
Old 03-21-2005, 09:59 AM
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the problem is i do not have a scan tool to read these codes. Do i need the scan tool to do this?
Old 03-21-2005, 10:43 AM
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Originally Posted by cccp
the problem is i do not have a scan tool to read these codes. Do i need the scan tool to do this?
Most FSM's (Factory Service Manuals) and Haynes-type manuals will have a section listing the malfunction in conjunction with the code displayed (the one that you pull while jumping from one terminal to the other).
Old 03-21-2005, 12:04 PM
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No tool required. You read the codes by watching how many times your check engine light blinks. All you need is a small section of wire. The error code readers just make it easier to do. Otherwise a place like Autozone may be able to do it for you, but I'm not for sure.

Now that I am reminded, I believe the manual that came with your truck does indeed have the codes listen it it. Chilton/Haynes/etc. repair manuals all have them, and are definitely worth the money as they tell you how to diagnose a lot of things by yourself.
Old 03-22-2005, 02:31 AM
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Check this link out. It helped me with the code problem
http://www.troublecodes.net/Toyota/
Old 03-22-2005, 03:10 AM
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Here's a very good explanation of trouble codes and how to check them:
http://www.off-road.com/toyota/tech/codes/
It even shows a picture of the diagnostic connector.
Old 03-23-2005, 07:25 AM
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i checked the code it was RPM signal(have no idea what that is) and it read main oxygen sensor. How bad is this? What should i do? I reseted in the check engine light by taking out the fuse out of the EFI for about ten minutes and it still is not light up.
Old 03-23-2005, 10:39 AM
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If it is the 02 sensor then it will not be a hard fix. Shouldn't be too much $$ either. If you get a well engineered sensor, it will be a simple R&R install. If you get some generic sensor, then you may have to do some crimping or soldering.

How has your MPG been lately?
Old 03-25-2005, 07:25 AM
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everything is fine the check engine is not going on. MPG are fine too, just like they always have been. Can i still drive my car everyday.
Old 03-26-2005, 04:45 PM
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This afternoon I was driving down the highway and my 'check engine light' came on also!! im at 70k miles on a 98 tacoma 4cyl.
Old 03-26-2005, 04:51 PM
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Originally Posted by DonH
This afternoon I was driving down the highway and my 'check engine light' came on also!! im at 70k miles on a 98 tacoma 4cyl.
Welcome to the forum!

The normal course of action at this point is to get to a Schuck's, AutoZone, Napa, etc. store and let them read the diag code for you. They won't charge you for the service like a dealer would.

Once you have the code, bring it back here and we'll be happy to help give you some ideas on what it means and how to go about repairing the fault.
Old 03-28-2005, 12:31 PM
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Just got back from my local garage. Theck were able to check the code for me. Its 'PO 171' which they say indicates a faulty oxygen sensor. Is this correct? Im wondering if it can be anything else.
Thanks in advance!!
Don
Old 03-28-2005, 12:58 PM
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Originally Posted by DonH
Just got back from my local garage. Theck were able to check the code for me. Its 'PO 171' which they say indicates a faulty oxygen sensor. Is this correct? Im wondering if it can be anything else.
Well, P0171 is actually "System too Lean (Bank 1)", and this "can" be caused by a faulty O2 sensor.

It can also be caused by anything that disrupts how the ECU computes and/or how the fuel system delivers fuel into the engine. That would be... fuel pump, injectors, air filter, dirty throttle body, O2 sensor, dirty MAF, TPS... and some other things.

Basically, the code is saying that the engine is running too lean, and it gets this information from the front O2 sensor. Personally, I would give the sensor the benefit of the doubt, (i.e., figure that it's not broken) and say it's doing it's job - so you need to look elsewhere.


Did the garage clear the code for you? If so, then wait and see if it comes back.
Old 03-28-2005, 01:21 PM
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I am guessing its the MAF since you were mudding. Probably got a little dirt on it and It's throwing the code. It doesn't cost anything or hurt to clean it anyways.


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