Light has been on and off for 2 years. Found NO vacuum leaks but sensor still reads lean and fuel keeps dumping. 1990 4X4 and it's my tractor but has to pass smog every 2 years. Read an article that mentioned the IAC. Made sense to me and I have a spare throttle body so I went for the IAC which is inside the body, It was a carbon mess and got a shot of oven cleaner to get to the plunger and seat (don't spray any sensor or switch). The plunger and seat were carboned up and cleaned easy. Reassembled and installed on truck. Responds to idle screw adjustment and runs much smoother. Test drove over 20 miles of mountain roads. NO code 25. I will know for sure in 4 or 5 days.
that's what I need to do, check my air vacuum lines especially the same one you pointed out. I keep getting code 21 and I just replaced the oxygen sensor.. thanks for the video.
I get a code 43 & 25 on my 1991 4runner 4x4 manual shift Toyota. I do know for a fact that the smaller companion hose that attaches directly from the larger accordian looking hose you pointed out and attaches at the other end to the valve cover is cracked at the valve cover. So that shall be an easy fix. As for code 43 I think it is an Electronic Spark Control Fault. Last month I finally rebuilt my engine after sitting for 4 years. Before installing the engine I also replaced the heater core. To replace the heater core I had to remove the whole dash board and also the ECM. Most likely the code 43 has to do with me not connecting the ECM properly and tight to the passenger kick panel metal frame. I'll come back to post the outcome. Update, October 30, 2021. I. Code 43 according to my Haynes manual is a "Starter Signal." The subcategory of problems is (1) IG switch circuit. (2) IG switch. (3) ECU. I'm assuming that IG means ignition. My ignition switch eventually didn't work. As I turned the key over, the engine wouldn't crank or make any ticking noise. I simply fixed this problem by connecting a long negative & positive wires directly to the starter & to a press-in button switch that I installed on a hidden place. To start my engine, I simply put my key in the ignition switch & then to the ON position, then I press the button...& the engine starts. So I use it like a kill switch. Any one attempting to rip off my 4Runner won't be able to hot wire it or by breaking the ignition switch. A month later I also replaced the starter because the solenoid eventually got stuck & didn't crank the engine. Months later when I checked the Self Diagnostics codes, the Code 43 was gone. I realized that I had unknowingly fixed the problem that gave the Code 43. II. As for my Code 25, I was wrong. It was a Code 52. Pay very close attention when checking the problem codes, make sure you start counting the number of times the check engine flashes right from the beginning as soon as you put the key to the ON position. Thanks to J asking me a question, I checked the codes & I realized that if I didn't pay attention as soon as I put the key on the ON position & didn't start counting the flashes as soon as they start, I could accidently invert the numbers. Last night I realized my problem code was actually Code 52. Haynes manual says it's a "Knock Sensor Signal." There's an "open circuit in knock sensor signal." The subcategory of problems is: (1) Knock sensor circuit, (2) knock sensor, or (3) ECU. (4) wire that connects knock sensor & to the harness wire. (5) Wire in the wire harness that leads to the ECU. 4 & 5 are not mentioned in the Haynes Manual. Replacing a 2 inch knock sensor requires a whole days worth of work since the whole intake system has to be remove & the whole front end of the engine. So might as well spend the $200 for an OEM Toyota 4Runner. No sense in doing so much work to install a cheap $30 knock sensor that may not work, then you have to spend yet another whole day to eventually replace it with an OEM sensor. All things can go wrong reinstalling everything...accidently set the timing belt wrong, connecting vacuum lines wrong, invert 2 spark plug wires wrong as I recently did...chased my tail several times before realizing my mistake. By the way, since I did replaced the knock sensor wire 2 years ago with an OEM Toyota wire, I know that wont be the problem. Since I did replace the knock sensor with a junkyard engine sensor, I'm sure this is the problem. A real shame because before rebuilding my engine, the knock sensor on my engine was good, I had no code 52. I will update this super long post, once I solve the problem. Probably sometime late next year.
Yo I got a question I bought my 91 4runner manual 4x4 and the hoses that run off the valve covers were both cracked off at the base would I have to buy a special hose to replace that or what would I need to do
@@coop_69 You mean the one for the PCV valve? Yes it's best to buy it instead of trying to match a coolant hose with a similar shape. Check out Yotashop.com. I buy many of the replacement parts through them. The PCV valve breather/vent hose is #12261-65010 for $25.99. You might as well replace the rubber PCV Valve Grommet #90480-18001 for $5.95. Or are you talking about all the bunch of skinny little vacuum lines? To replace those, just go to Autozone. They sell them in a roll of maybe 4ft. in length. Just pull one line & take it to them to size up. Make sure you cut each line several inches longer, maybe 3 inches longer than the original one & replace them all one by one. It is a tight fitting in that area & they easily pull right off. The extra inches per line will give you easy wiggle room to gently move them around to check the surrounding area when you search for oil or coolant leaks & to be able to check in the future if any hoses popped out when the 4R starts running crappy. Doing this allowed me to get in there in tight places with my cell phone while recording video. Replaying the video I found out that I missed connecting a ground wire from the main wire harness that goes attached to the rear camshaft cap (passenger side), the one that is outside the rear of the valve cover. Oh by the way, on my original posting I referred to a part as a acordian looking hose, that's actually the throttle body air hose to the air filter box.
@@johnnyjohn8073 yeah it would be the pcv valve hose it was very brittle and broken off at the end but for the grommet where would that be located cause I couldn't see a spot for it. And thanks so much for the part numbers
@@coop_69 These parts are all connected together: PCV Grommet, PCV Valve, & PCV Vent/Air Hose. At one end of these connections, The PCV Grommet is inserted on a hole on top of the valve cover, passenger side (U.S.). The PCV Valve (#12204-65010 $9.15 ) is also inserted into the valve cover but through the PCV Grommet. Note: The grommet is just a seal that prevents oil & air from leaking out of the valve cover. The PCV Air/Vent Hose is connected to the PCV Valve at the top end. The PCV Air/Vent Hose is connected to the AS Reed Valve at the bottom end. A metal tube at the bottom of the AS Reed Valve connects to the engine block. Note: The AS Reed Valve is sometimes called a Pair Reed Valve or simply, Pair Valve.
Had code 22 on my 95 4runner, finally found the coolant temp. sensor. Dang thing wasnt fully plugged in. Big relief , simple fix. Looked ok but when I actually got fingers on the plug , it separated. Cleared code. Done.
Did you fix your problem? I currently get also code 25 but also code 43 on my 1991 4runner 3.0. I replaced the same Air Flow Meter as this guy did & the same thing happened, the check engine light remained off momentarily then eventually came back on even though I cleared all the codes as per he Haynes Manual. It does run better but I still get a strong gasoline smell just like I did with the previous Air Flow Meter. After doing a vacuum check with a home made smoke can, I will replace my O2 Sensor; but first I'll clean the old one as some people here on RUclips have demonstrated how to clean it.
@@None-ij7zz Thanks for your question because you got me to look in my Haynes manual for the codes page again & to perform the self diagnostics test again last night. I discovered that I don't have, nor did I have a code 25. It is actually a code 52. I've been driving my 4runner all this time without fixing the problem that triggers that code but now I have to fix it because my tags expired last month & I have to smog it. I've had no rush to fix it because the 4runner actually runs really nice with no performance issues that are noticeable in street driving or highway driving up to 80mph. A code 52 is a Knock Sensor related problem. The subcategories of problems can either be a (1) bad knock sensor itself, (2) bad wire to the knock sensor which I actually replaced 2 years ago with an OEM wire from YotaShop when I installed my newly rebuilt engine. It could be a (3) bad knock sensor wire from the wire harness leading to the ECU. Finally, it could be a (4) bad ECU. Most likely it's a bad knock sensor because I used a junkyard engine sensor to replace mines. Big mistake because my knock sensor actually had no problem, it just looked dirty & older. The problem is that it's a whole day of work to remove everything in order to get to a 2inch sensor. Second problem, it's so much work that I might as well use an OEM Toyota knock sensor...problem, it's $200. I may simply drill a hole on the engine pulling bracket, make threads on it, & install a cheap new knock sensor & connect the wire. I've seen someone on youtube bipass the location of the knock sensor & the check engine light for code 52 was cleared. If the code goes away, it's a good indication that the knock sensor on my engine block is bad and now I can feel comfortable spending the $200 for an OEM sensor, knowing for sure this is the problem. Last night when I looked up the codes, I realized I could have confused code 25 & 52 if I started counting the Check Engine number of flashes at the wrong time. Last night I made sure I started counting the number of flashes as soon as I put the key from the OFF position, to the ON position. The number of flashes was 5-flashes, pause, 2-flashes: Code 52. Two years ago I accidently counted the flashes at the wrong time when the 2-flashes first appeared, not realizing that 5 had already flashed. Hope I'm not confusing you. So all this time I thought I had a code 25. A Code 25 is a Low Air-Fuel ratio problem that has countless subcategories as for its cause, including the O2 Sensor circuitry, vacuum leaks that cause this lean air-fuel mix since a vacuum leak is excessive air going into the intake system. Good luck with that. The old 4Runners are a spaghetti plate of vacuum lines & hoses under the engine bay. That's why I replaced them all with new & longer lines to give the area more wiggle space to view & check for lines that slip off or are cracked. The old vacuum lines & hoses are way too short & give you no wiggle room to move them out of the way in order to inspect or work near the area, such as replacing the spark plugs on the driver side. The old short length lines are too tight in there so they can easily come lose or crack. I hope you find your problem. I highly recommend replacing each one, one at a time with longer lines.
I get the 25 code but the check engine light doesnt actually come on. Is that a sign of a particular problem? Alot of the time i hear people say they have a check engine light and the code 25..
In the diagnostic plug take a little jumper wire (speaker wire or something) and jump E1 to TE1 (they’re labeled under the cap) , get in and turn the key on, check engine light will flash the codes...google can give you a more detailed run down
@@rasbe420 That's correct but the Haynes Manual page 6-38 requires that the engine be warmed up at normal operating temperature. The temperature gauge on the dash has to be pointing at half on the little clear window. Cars that don't have E1 & TE1 on the black little diagnostics box in the engine bay will need to use E & T. My 1991 4Runner has the diagnostics box next to the relay box on the right (passenger) fender. (1) So start the car and run it till the temperature is half way. Run it for a while at this temperature level. Driving the car to get it at this half level is faster than simply keeping the car at idle while it's parked. (2) Turn off the car once the temperature is halfway at normal operating temperature, remove the keys or simply keep it on the OFF position on the ignition switch. (3) Use a paper clip & shape it into a U-shape. (4) Stick one end of the paper clip into E1. (5) Stick the other end of the paper clip into TE1, don't worry this will not shock you. (6) Put your keys in the ignition switch again & turn it to the ON position but don't turn on the car. If you accidently do turn on the car, don't worry & simply turn it off and put it to the ON position. Use your cell phone to record the sequence of flashes that the Check Engine light flashes so you can review it over & over till you feel secure that you understood the codes. Start recording before you put the key to the ON positions. The sequence of code flashing will repeat over & over & over till you put the key on OFF or remove them. Code 25 Example 1: 2 Blinks - followed by a 3 second pause - 5 Blink. Don't count 2 + 5 = 7. The code is 7. NO THIS IS WRONG. Code 25 Example 2: Blink Blink - PAUSE 3 seconds - Blink Blink Blink Blink Blink. 2Blinks then 5Blinks is Code 25. I also have a Code 43: Blink Blink Blink Blink - Pause - Blink Blink Blink. Ras Be I'm sure you know how to do this, I'm just posting it for other readers that may not be aware.
Thanks for uploading and helping the 3.0 4 runner community!
It will come back on!!!! GUARANTEED!!!
Light has been on and off for 2 years. Found NO vacuum leaks but sensor still reads lean and fuel keeps dumping. 1990 4X4 and it's my tractor but has to pass smog every 2 years. Read an article that mentioned the IAC. Made sense to me and I have a spare throttle body so I went for the IAC which is inside the body, It was a carbon mess and got a shot of oven cleaner to get to the plunger and seat (don't spray any sensor or switch). The plunger and seat were carboned up and cleaned easy. Reassembled and installed on truck. Responds to idle screw adjustment and runs much smoother. Test drove over 20 miles of mountain roads. NO code 25. I will know for sure in 4 or 5 days.
Did it ever come back?
that's what I need to do, check my air vacuum lines especially the same one you pointed out. I keep getting code 21 and I just replaced the oxygen sensor.. thanks for the video.
Hope you figure it out. My check engine light has been off ever since.
Probably your wiring or ecu the board where you 02 goes to computer is probably fried
I get a code 43 & 25 on my 1991 4runner 4x4 manual shift Toyota. I do know for a fact that the smaller companion hose that attaches directly from the larger accordian looking hose you pointed out and attaches at the other end to the valve cover is cracked at the valve cover. So that shall be an easy fix. As for code 43 I think it is an Electronic Spark Control Fault. Last month I finally rebuilt my engine after sitting for 4 years. Before installing the engine I also replaced the heater core. To replace the heater core I had to remove the whole dash board and also the ECM. Most likely the code 43 has to do with me not connecting the ECM properly and tight to the passenger kick panel metal frame. I'll come back to post the outcome.
Update, October 30, 2021.
I. Code 43 according to my Haynes manual is a "Starter Signal." The subcategory of problems is (1) IG switch circuit. (2) IG switch. (3) ECU. I'm assuming that IG means ignition. My ignition switch eventually didn't work. As I turned the key over, the engine wouldn't crank or make any ticking noise. I simply fixed this problem by connecting a long negative & positive wires directly to the starter & to a press-in button switch that I installed on a hidden place. To start my engine, I simply put my key in the ignition switch & then to the ON position, then I press the button...& the engine starts. So I use it like a kill switch. Any one attempting to rip off my 4Runner won't be able to hot wire it or by breaking the ignition switch. A month later I also replaced the starter because the solenoid eventually got stuck & didn't crank the engine. Months later when I checked the Self Diagnostics codes, the Code 43 was gone. I realized that I had unknowingly fixed the problem that gave the Code 43.
II. As for my Code 25, I was wrong. It was a Code 52. Pay very close attention when checking the problem codes, make sure you start counting the number of times the check engine flashes right from the beginning as soon as you put the key to the ON position. Thanks to J asking me a question, I checked the codes & I realized that if I didn't pay attention as soon as I put the key on the ON position & didn't start counting the flashes as soon as they start, I could accidently invert the numbers. Last night I realized my problem code was actually Code 52. Haynes manual says it's a "Knock Sensor Signal." There's an "open circuit in knock sensor signal." The subcategory of problems is: (1) Knock sensor circuit, (2) knock sensor, or (3) ECU. (4) wire that connects knock sensor & to the harness wire. (5) Wire in the wire harness that leads to the ECU. 4 & 5 are not mentioned in the Haynes Manual. Replacing a 2 inch knock sensor requires a whole days worth of work since the whole intake system has to be remove & the whole front end of the engine. So might as well spend the $200 for an OEM Toyota 4Runner. No sense in doing so much work to install a cheap $30 knock sensor that may not work, then you have to spend yet another whole day to eventually replace it with an OEM sensor. All things can go wrong reinstalling everything...accidently set the timing belt wrong, connecting vacuum lines wrong, invert 2 spark plug wires wrong as I recently did...chased my tail several times before realizing my mistake. By the way, since I did replaced the knock sensor wire 2 years ago with an OEM Toyota wire, I know that wont be the problem. Since I did replace the knock sensor with a junkyard engine sensor, I'm sure this is the problem. A real shame because before rebuilding my engine, the knock sensor on my engine was good, I had no code 52. I will update this super long post, once I solve the problem. Probably sometime late next year.
Yo I got a question I bought my 91 4runner manual 4x4 and the hoses that run off the valve covers were both cracked off at the base would I have to buy a special hose to replace that or what would I need to do
@@coop_69 You mean the one for the PCV valve? Yes it's best to buy it instead of trying to match a coolant hose with a similar shape. Check out Yotashop.com. I buy many of the replacement parts through them. The PCV valve breather/vent hose is #12261-65010 for $25.99. You might as well replace the rubber PCV Valve Grommet #90480-18001 for $5.95. Or are you talking about all the bunch of skinny little vacuum lines? To replace those, just go to Autozone. They sell them in a roll of maybe 4ft. in length. Just pull one line & take it to them to size up. Make sure you cut each line several inches longer, maybe 3 inches longer than the original one & replace them all one by one. It is a tight fitting in that area & they easily pull right off. The extra inches per line will give you easy wiggle room to gently move them around to check the surrounding area when you search for oil or coolant leaks & to be able to check in the future if any hoses popped out when the 4R starts running crappy. Doing this allowed me to get in there in tight places with my cell phone while recording video. Replaying the video I found out that I missed connecting a ground wire from the main wire harness that goes attached to the rear camshaft cap (passenger side), the one that is outside the rear of the valve cover. Oh by the way, on my original posting I referred to a part as a acordian looking hose, that's actually the throttle body air hose to the air filter box.
@@johnnyjohn8073 yeah it would be the pcv valve hose it was very brittle and broken off at the end but for the grommet where would that be located cause I couldn't see a spot for it. And thanks so much for the part numbers
@@coop_69 These parts are all connected together: PCV Grommet, PCV Valve, & PCV Vent/Air Hose.
At one end of these connections, The PCV Grommet is inserted on a hole on top of the valve cover, passenger side (U.S.). The PCV Valve (#12204-65010 $9.15 ) is also inserted into the valve cover but through the PCV Grommet.
Note: The grommet is just a seal that prevents oil & air from leaking out of the valve cover.
The PCV Air/Vent Hose is connected to the PCV Valve at the top end.
The PCV Air/Vent Hose is connected to the AS Reed Valve at the bottom end.
A metal tube at the bottom of the AS Reed Valve connects to the engine block.
Note: The AS Reed Valve is sometimes called a Pair Reed Valve or simply, Pair Valve.
@@johnnyjohn8073 I'm deleting the pair valve and the egr so could I block that off or would it have to be connected
Had code 22 on my 95 4runner, finally found the coolant temp. sensor. Dang thing wasnt fully plugged in. Big relief , simple fix. Looked ok but when I actually got fingers on the plug , it separated. Cleared code. Done.
thanks man im getting the same code on my 95 4runner im gonna give this a shot
Did you fix your problem? I currently get also code 25 but also code 43 on my 1991 4runner 3.0. I replaced the same Air Flow Meter as this guy did & the same thing happened, the check engine light remained off momentarily then eventually came back on even though I cleared all the codes as per he Haynes Manual. It does run better but I still get a strong gasoline smell just like I did with the previous Air Flow Meter. After doing a vacuum check with a home made smoke can, I will replace my O2 Sensor; but first I'll clean the old one as some people here on RUclips have demonstrated how to clean it.
@@johnnyjohn8073 what finally fixed your code 25?
@@None-ij7zz Thanks for your question because you got me to look in my Haynes manual for the codes page again & to perform the self diagnostics test again last night. I discovered that I don't have, nor did I have a code 25. It is actually a code 52. I've been driving my 4runner all this time without fixing the problem that triggers that code but now I have to fix it because my tags expired last month & I have to smog it. I've had no rush to fix it because the 4runner actually runs really nice with no performance issues that are noticeable in street driving or highway driving up to 80mph. A code 52 is a Knock Sensor related problem. The subcategories of problems can either be a (1) bad knock sensor itself, (2) bad wire to the knock sensor which I actually replaced 2 years ago with an OEM wire from YotaShop when I installed my newly rebuilt engine. It could be a (3) bad knock sensor wire from the wire harness leading to the ECU. Finally, it could be a (4) bad ECU. Most likely it's a bad knock sensor because I used a junkyard engine sensor to replace mines. Big mistake because my knock sensor actually had no problem, it just looked dirty & older. The problem is that it's a whole day of work to remove everything in order to get to a 2inch sensor. Second problem, it's so much work that I might as well use an OEM Toyota knock sensor...problem, it's $200. I may simply drill a hole on the engine pulling bracket, make threads on it, & install a cheap new knock sensor & connect the wire. I've seen someone on youtube bipass the location of the knock sensor & the check engine light for code 52 was cleared. If the code goes away, it's a good indication that the knock sensor on my engine block is bad and now I can feel comfortable spending the $200 for an OEM sensor, knowing for sure this is the problem.
Last night when I looked up the codes, I realized I could have confused code 25 & 52 if I started counting the Check Engine number of flashes at the wrong time. Last night I made sure I started counting the number of flashes as soon as I put the key from the OFF position, to the ON position. The number of flashes was 5-flashes, pause, 2-flashes: Code 52. Two years ago I accidently counted the flashes at the wrong time when the 2-flashes first appeared, not realizing that 5 had already flashed. Hope I'm not confusing you. So all this time I thought I had a code 25. A Code 25 is a Low Air-Fuel ratio problem that has countless subcategories as for its cause, including the O2 Sensor circuitry, vacuum leaks that cause this lean air-fuel mix since a vacuum leak is excessive air going into the intake system. Good luck with that. The old 4Runners are a spaghetti plate of vacuum lines & hoses under the engine bay. That's why I replaced them all with new & longer lines to give the area more wiggle space to view & check for lines that slip off or are cracked. The old vacuum lines & hoses are way too short & give you no wiggle room to move them out of the way in order to inspect or work near the area, such as replacing the spark plugs on the driver side. The old short length lines are too tight in there so they can easily come lose or crack. I hope you find your problem. I highly recommend replacing each one, one at a time with longer lines.
Do you have a upstream and downstream Oxygen Sensor on that 4 Runner ? If so which did you replace . Is it by the Catalytic converter ?
I get the 25 code but the check engine light doesnt actually come on. Is that a sign of a particular problem? Alot of the time i hear people say they have a check engine light and the code 25..
Where do you find that intake tube (hose) that you replaced?
Amazon
Thanks
You never point to why you replaced…
Cuz code 25 is lean it’s in the description
LET IT SIT FOR FEW MONTHSSSS !!!!!!!!😆😆😆😆
what do you do when check engine light is on but you cant get it to give a code?
Could this code cause the car to smoke a little bit?
I doubt it. Not sure though. Mine did not.
Yes mine has this issue
Did you notice better mpg's after the new sensor was put in?
Yes I did. About 2-3 more mpg
👍💯
How do you find our how it was a code 25. I have the check engine light that has come on but I don’t know how I check the code
In the diagnostic plug take a little jumper wire (speaker wire or something) and jump E1 to TE1 (they’re labeled under the cap) , get in and turn the key on, check engine light will flash the codes...google can give you a more detailed run down
@@rasbe420 That's correct but the Haynes Manual page 6-38 requires that the engine be warmed up at normal operating temperature. The temperature gauge on the dash has to be pointing at half on the little clear window. Cars that don't have E1 & TE1 on the black little diagnostics box in the engine bay will need to use E & T. My 1991 4Runner has the diagnostics box next to the relay box on the right (passenger) fender.
(1) So start the car and run it till the temperature is half way. Run it for a while at this temperature level. Driving the car to get it at this half level is faster than simply keeping the car at idle while it's parked. (2) Turn off the car once the temperature is halfway at normal operating temperature, remove the keys or simply keep it on the OFF position on the ignition switch. (3) Use a paper clip & shape it into a U-shape. (4) Stick one end of the paper clip into E1. (5) Stick the other end of the paper clip into TE1, don't worry this will not shock you. (6) Put your keys in the ignition switch again & turn it to the ON position but don't turn on the car. If you accidently do turn on the car, don't worry & simply turn it off and put it to the ON position. Use your cell phone to record the sequence of flashes that the Check Engine light flashes so you can review it over & over till you feel secure that you understood the codes. Start recording before you put the key to the ON positions. The sequence of code flashing will repeat over & over & over till you put the key on OFF or remove them.
Code 25 Example 1: 2 Blinks - followed by a 3 second pause - 5 Blink.
Don't count 2 + 5 = 7. The code is 7. NO THIS IS WRONG.
Code 25 Example 2: Blink Blink - PAUSE 3 seconds - Blink Blink Blink Blink Blink.
2Blinks then 5Blinks is Code 25.
I also have a Code 43: Blink Blink Blink Blink - Pause - Blink Blink Blink.
Ras Be I'm sure you know how to do this, I'm just posting it for other readers that may not be aware.
@@johnnyjohn8073 i am one of those unaware readers. I appreciate you, thanks.
How do you get the code
The under hood diagnosis port you put a wire in Te1 and e1 ports and turn the ignition on. Count the flashes to read.
Still active on this channel? Give me a reply or a PM if so