Check engine light question

Stand alone P0125s are rare. I'd check PCV valve and connections, any air intake leaks after the MAF, anf exhaust leaks.



http://www.teamtoyota4x4.org/archiv...2rmsour/2002/024runne/di/eg5vzfe/cip0125o.pdf



This is for a 2002 with the A/F sensor, but it gives you an idea. I don't know where to find your year on-line.



The link didn’t work for me but what you said gives me an idea where to go next...this thing has what looks like a home made intake, thought about changing it out since it came with what’s supposed to be there....that’s a project for tomorrow
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67f2c3d728c5e9f2fddf8e1c12e6f540.jpg



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The link didn’t work for me but what you said gives me an idea where to go next...this thing has what looks like a home made intake, thought about changing it out since it came with what’s supposed to be there....that’s a project for tomorrow


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The link is good, but those usually won't work from an iPhone. Usually takes a laptop or desjtop to read those .pdf files.

But yeah, that is for sure a suspect area. To test for leaks, spraying it with water while it is running will catch a big one . Smaller ones can be chased with flammables (water makes it die, flammables speed it up). People use propane, brake cleaner, etc. Find a few videos so you don't kill yourself and blow up your rig.
 
The link didn’t work for me but what you said gives me an idea where to go next...this thing has what looks like a home made intake, thought about changing it out since it came with what’s supposed to be there....that’s a project for tomorrow
67f2c3d728c5e9f2fddf8e1c12e6f540.jpg
67f2c3d728c5e9f2fddf8e1c12e6f540.jpg



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That's someone's attempt at the intake silencer removal mod, supposedly increases HP. I'm skeptical if it really even works, there's no dyno proof anywhere. That pipe is definitely past it's prime though.
 
That's someone's attempt at the intake silencer removal mod, supposedly increases HP. I'm skeptical if it really even works, there's no dyno proof anywhere. That pipe is definitely past it's prime though.



Swapped that out and had to laugh at the valve stem installed in the tube for that line to connect to, anyway I put in what belongs there, cleared the code and test drove it only to come back, thinking of changing out the coolant temp sensor but if I’m getting a coolant temp reading (196-202) wouldn’t that tell me it’s not the coolant temp sensor


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Changed thermostat, new rad cap, cleaned MAF, still have the CEL and P0125

Possibly dumb question and I'm not saying you haven't, but they get missed pretty often so I'm throwing it out there:

When you cleaned the MAF you cleaned the two teeny silver sensor wires that require a little looking for and not just the brownish air temp sensor that is easy to see?
 
Possibly dumb question and I'm not saying you haven't, but they get missed pretty often so I'm throwing it out there:

When you cleaned the MAF you cleaned the two teeny silver sensor wires that require a little looking for and not just the brownish air temp sensor that is easy to see?



I did not, going to check that now


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Did some playing with the scanner, can anyone help me decipher any of this, I’m thinking O2 sensor but that’s an expensive guess if I’m wrong
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Well, the headline is you recently reset it, your evap and catalyst tests are still incomplete, your MIL is on, you have one code, and you didn't show us the screen where that code is displayed. No way to diagnose anything without that, and better to let the tests complete and look at the full set of DTCs, because there may be more when they do.
 
Well, the headline is you recently reset it, your evap and catalyst tests are still incomplete, your MIL is on, you have one code, and you didn't show us the screen where that code is displayed. No way to diagnose anything without that, and better to let the tests complete and look at the full set of DTCs, because there may be more when they do.



The code that is displayed is P0125 that’s the only code that comes up



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Also if the tests are incomplete how do you complete them....
New thermostat, new rad cap, cleaned MAF, swapped out that homemade intake silencer tube, checked for air leaks, cleared code and test drive multiple times and CEL comes on about 5 minutes into test drive.
Code P0125 Insufficient coolant temp for closed loop fuel control


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Yeah. This. I was thinking it might be a P0125: Insufficient Coolant Temperature for Closed Loop Fuel Control which a parts store dumbo could think was a thermostat, but is usually an O2 sensor.



That is what came up when I finally got a scanner, the parts store scanner only showed that the thermostat was the issue, what a great sell up. I bet that wasn’t even bad.


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Here's what's from the FSM, although this is for a 2002 but similar:

P0125

Insufficient Coolant Temp. for Closed Loop Fuel Control
 Open or short in A/F sensor (bank 1 sensor 1) circuit
 A/F sensor (bank 1 sensor 1) - you don't have an A/F sensor, just a narrowband O2
 Air induction system
 Fuel pressure
 Injector
 Gas leakage on exhaust system
 PCV valve and hose
ECM

Says to check your PCV hose and valve first, to be honest it's about $5 for the PCV valve, grommet, and a replacement hose so that might be another place to check for cheap. No way to tell if it's working unless you replace it, they can get all gunked up inside due to oil sludge.

Other than that, it says check for damage on the front O2 sensor wiring, then replace the sensor if wiring is good.

By the way, it says running out of fuel can cause a P0125. Did you run out of fuel recently?
 
Here's what's from the FSM, although this is for a 2002 but similar:

P0125

Insufficient Coolant Temp. for Closed Loop Fuel Control
Open or short in A/F sensor (bank 1 sensor 1) circuit
A/F sensor (bank 1 sensor 1) - you don't have an A/F sensor, just a narrowband O2
Air induction system
Fuel pressure
Injector
Gas leakage on exhaust system
PCV valve and hose
ECM

Says to check your PCV hose and valve first, to be honest it's about $5 for the PCV valve, grommet, and a replacement hose so that might be another place to check for cheap. No way to tell if it's working unless you replace it, they can get all gunked up inside due to oil sludge.

Other than that, it says check for damage on the front O2 sensor wiring, then replace the sensor if wiring is good.

By the way, it says running out of fuel can cause a P0125. Did you run out of fuel recently?



I’ll do the pcv, this thing was sitting for 5 years, as for running out of gas, no...but I only put about 200 miles on it since I got it and got it into running condition.
O2 wiring looks good, no mice chews there.
Thank you


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Well it’s been a long and hot weekend of trying to take care of CEL.
New Thermostat [emoji736]
New rad cap[emoji736]
New grommet and pcv[emoji736]
Cleaned MAF[emoji736]
Checked for air leaks[emoji736]
Picked up new o2 sensor.....nuts are so rusted that they are no longer 12mm, 11mm slips. Giving up for today....I’ll get back to it maybe on the 4th, for now going to soak them with penetration fluid.
I want to thank everyone that took the time to comment with ideas.
Again thank you


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I’ll do the pcv, this thing was sitting for 5 years, as for running out of gas, no...but I only put about 200 miles on it since I got it and got it into running condition.
O2 wiring looks good, no mice chews there.
Thank you


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Wait, I think I missed that! Have you filled up the tank with some fresh gas yet? Put in a couple of fuel injector cleaner bottles?
 
Wait, I think I missed that! Have you filled up the tank with some fresh gas yet? Put in a couple of fuel injector cleaner bottles?



So far I ran one fresh tank, I thought about injector cleaner while I was at parts store, I guess I’ll be picking some up after work and going to fill the tank and put some miles on it



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So far I ran one fresh tank, I thought about injector cleaner while I was at parts store, I guess I’ll be picking some up after work and going to fill the tank and put some miles on it



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Old gas can cause some really funny issues so it's worth a shot. Will only cost you $10 and a couple minutes of your time anyway.
 
Picked up new o2 sensor.....nuts are so rusted that they are no longer 12mm, 11mm slips.

The magic bullet for those nuts is to heat them up until they're glowing red, then they should come off easy with vice grips.

If that doesn't work, heat them up until red, hose them down with penetrating oil, then heat again. That will do the trick 99% of the time for rusted fasteners.
 

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