92 Sc400 Code 25 Air Fuel Ratio Lean Malfunction
92 Sc400 Code 25 Air Fuel Ratio Lean Malfunction
WTF is that??? lol I just checked for codes and this is what comes up.. Whats sets it off?? My car runs crazy rich and burns alot of gas. Anyone have a solution to this.. I got a long trip im taking my car on so any help would be appreciated.. I did do a search, i got iacv(idle air control valve) anyone find something else that might be faulty??
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Joined: Aug 2010
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From: markham,ill
i just had a full tune up done (timing belt,water pump,belt tensioner,caps,rotors,plugs,wires,and coils) and still having this problem.now waiting on low coolant sensor to come.{caution dont drive it as right now you'll burn up catalyc converters
That could be so many things. You need to start with how your car is acting, and do some deductions from that.
Just from that code, it could be the IACV, a vacuum leak, bad pcv valve, dirty/bad injectors, dirty air filter, exhaust leak, bad maf, bad O2 sensor, broken/open dipstick plug, fuel pressure loss somewhere, or simply bad gas (too much moisture in your fuel lines).....
To check IACV. Have car warmed up and at idle. Turn the steering wheel. Does it almost stall?
To check vacuum leak. Buy a can of Brake Cleaner and gently spray your hoses while the car is running. If idle changes then you found your leak. Do the same for the pcv valve.
To find an exhaust leak. Seafoam the car through the brake booster. When its time to turn on have someone check the exhaust pipes for white smoke. That'll tell you where the exhaust leak is at.
To find out if its the injectors. Reset the ecu and let the car warm up. When it's fully warm is the idle really really low? Does the car shake a little?
To clean the maf. Since your car is a 92-95, clean it with compressed air, electric parts cleaner, or VERY gently with alcohol. Do not use the hotwire maf cleaner from the store.
It's easy to check the filter/gas...
To check the O2 sensor, this would be the last thing to look at. (Process of deduction) If everything else is good then it might be the O2 sensors.
Just from that code, it could be the IACV, a vacuum leak, bad pcv valve, dirty/bad injectors, dirty air filter, exhaust leak, bad maf, bad O2 sensor, broken/open dipstick plug, fuel pressure loss somewhere, or simply bad gas (too much moisture in your fuel lines).....
To check IACV. Have car warmed up and at idle. Turn the steering wheel. Does it almost stall?
To check vacuum leak. Buy a can of Brake Cleaner and gently spray your hoses while the car is running. If idle changes then you found your leak. Do the same for the pcv valve.
To find an exhaust leak. Seafoam the car through the brake booster. When its time to turn on have someone check the exhaust pipes for white smoke. That'll tell you where the exhaust leak is at.
To find out if its the injectors. Reset the ecu and let the car warm up. When it's fully warm is the idle really really low? Does the car shake a little?
To clean the maf. Since your car is a 92-95, clean it with compressed air, electric parts cleaner, or VERY gently with alcohol. Do not use the hotwire maf cleaner from the store.
It's easy to check the filter/gas...
To check the O2 sensor, this would be the last thing to look at. (Process of deduction) If everything else is good then it might be the O2 sensors.
Last edited by sc-driver; Aug 20, 2010 at 02:23 PM.
That could be so many things. You need to start with how your car is acting, and do some deductions from that.
Just from that code, it could be the IACV, a vacuum leak, bad pcv valve, dirty/bad injectors, dirty air filter, exhaust leak, bad maf, bad O2 sensor, broken/open dipstick plug, fuel pressure loss somewhere, or simply bad gas (too much moisture in your fuel lines).....
To check IACV. Have car warmed up and at idle. Turn the steering wheel. Does it almost stall?
To check vacuum leak. Buy a can of Brake Cleaner and gently spray your hoses while the car is running. If idle changes then you found your leak. Do the same for the pcv valve.
To find an exhaust leak. Seafoam the car through the brake booster. When its time to turn on have someone check the exhaust pipes for white smoke. That'll tell you where the exhaust leak is at.
To find out if its the injectors. Reset the ecu and let the car warm up. When it's fully warm is the idle really really low? Does the car shake a little?
To clean the maf. Since your car is a 92-95, clean it with compressed air, electric parts cleaner, or VERY gently with alcohol. Do not use the hotwire maf cleaner from the store.
It's easy to check the filter/gas...
To check the O2 sensor, this would be the last thing to look at. (Process of deduction) If everything else is good then it might be the O2 sensors.
Just from that code, it could be the IACV, a vacuum leak, bad pcv valve, dirty/bad injectors, dirty air filter, exhaust leak, bad maf, bad O2 sensor, broken/open dipstick plug, fuel pressure loss somewhere, or simply bad gas (too much moisture in your fuel lines).....
To check IACV. Have car warmed up and at idle. Turn the steering wheel. Does it almost stall?
To check vacuum leak. Buy a can of Brake Cleaner and gently spray your hoses while the car is running. If idle changes then you found your leak. Do the same for the pcv valve.
To find an exhaust leak. Seafoam the car through the brake booster. When its time to turn on have someone check the exhaust pipes for white smoke. That'll tell you where the exhaust leak is at.
To find out if its the injectors. Reset the ecu and let the car warm up. When it's fully warm is the idle really really low? Does the car shake a little?
To clean the maf. Since your car is a 92-95, clean it with compressed air, electric parts cleaner, or VERY gently with alcohol. Do not use the hotwire maf cleaner from the store.
It's easy to check the filter/gas...
To check the O2 sensor, this would be the last thing to look at. (Process of deduction) If everything else is good then it might be the O2 sensors.
Lexus Champion
Joined: Jan 2014
Posts: 2,089
Likes: 52
From: illinois
sorry to bring this back from the grave but i got the same code and my car runs fine, sometimes a weird idle so ill check the IACV first and then MAF. i got a 92 SC400 btw any ideas on what else it could be and where to get some O2 sensors cz i dont think these have ever been replaced, car has 215k miles so they're probably in bad shape.
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i just recently had this code. changed all my 02's and it went away.
best best for 02's is oem or denso. i went denso was cheaper and the same product
check rockauto.com
best best for 02's is oem or denso. i went denso was cheaper and the same product
check rockauto.com
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If the o2's dont fix it, and if the ECU has never been touched, I'd say the ECU is the issue. Miles dont really matter on the car, it's the age, and those capacitors leak in 20 years. Probably need a rebuild.
Driver School Candidate
Joined: Feb 2017
Posts: 3
Likes: 0
From: NY
That could be so many things. You need to start with how your car is acting, and do some deductions from that.
Just from that code, it could be the IACV, a vacuum leak, bad pcv valve, dirty/bad injectors, dirty air filter, exhaust leak, bad maf, bad O2 sensor, broken/open dipstick plug, fuel pressure loss somewhere, or simply bad gas (too much moisture in your fuel lines).....
To check IACV. Have car warmed up and at idle. Turn the steering wheel. Does it almost stall?
To check vacuum leak. Buy a can of Brake Cleaner and gently spray your hoses while the car is running. If idle changes then you found your leak. Do the same for the pcv valve.
To find an exhaust leak. Seafoam the car through the brake booster. When its time to turn on have someone check the exhaust pipes for white smoke. That'll tell you where the exhaust leak is at.
To find out if its the injectors. Reset the ecu and let the car warm up. When it's fully warm is the idle really really low? Does the car shake a little?
To clean the maf. Since your car is a 92-95, clean it with compressed air, electric parts cleaner, or VERY gently with alcohol. Do not use the hotwire maf cleaner from the store.
It's easy to check the filter/gas...
To check the O2 sensor, this would be the last thing to look at. (Process of deduction) If everything else is good then it might be the O2 sensors.
Just from that code, it could be the IACV, a vacuum leak, bad pcv valve, dirty/bad injectors, dirty air filter, exhaust leak, bad maf, bad O2 sensor, broken/open dipstick plug, fuel pressure loss somewhere, or simply bad gas (too much moisture in your fuel lines).....
To check IACV. Have car warmed up and at idle. Turn the steering wheel. Does it almost stall?
To check vacuum leak. Buy a can of Brake Cleaner and gently spray your hoses while the car is running. If idle changes then you found your leak. Do the same for the pcv valve.
To find an exhaust leak. Seafoam the car through the brake booster. When its time to turn on have someone check the exhaust pipes for white smoke. That'll tell you where the exhaust leak is at.
To find out if its the injectors. Reset the ecu and let the car warm up. When it's fully warm is the idle really really low? Does the car shake a little?
To clean the maf. Since your car is a 92-95, clean it with compressed air, electric parts cleaner, or VERY gently with alcohol. Do not use the hotwire maf cleaner from the store.
It's easy to check the filter/gas...
To check the O2 sensor, this would be the last thing to look at. (Process of deduction) If everything else is good then it might be the O2 sensors.
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