P1131 error code
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P1131 error code
Hey guys I'm getting the p1131 error on my 2000 xlt f150 5.4l. I know it's usually a vacuum leak on the pcv hosing, which I did have at the back and replaced as well as other softer joining sections(3 to be exact lol), but I'm still getting this error. Changed out my plugs and cops(as they needed it) and the back two plugs on both bank 1 and 2(plugs 4&8) were both white! Since this is an obvious indication of a lean burning cylinder can I make the assumption my most likely problem is dirty fuel injectors on those cylinders? Yeah yeah I know I'd clean them all lol.
Thanks much Jacob
Thanks much Jacob
Lead Driver
Joined: Sep 2006
Posts: 7,907
Likes: 143
You need some instruction on this as follows;
The 1131 code is indicating an over rich appearing condition at the end of a PCM test that fails switching. This sets the specific code.
Best confirmed with a Scanner looking at live data from the sensor in question and compaired to the other side.
.
Secondly, you cannot judge an engine's performance from the plug tips or porcelain color that easily unless your an accomplished expert at it. On a carbed motor yes, on FI motor, no.
Reason is the OX sensors normally are so precision at controlling loop A/F ratio that the plugs will normally look white in a trouble free engine. This is why plug heat range is important in a FI motor.
For the 1131 code you could have one or more of the following; an air leak, short to power in the harness, water in the connector, corrosion in terminals, excessive fuel pressure, low fuel pressure, and a bunch of other possibilities that affect the fuel or air.
So you see it's not that easy. The PCM does this test and found an issue.
Best you can do is go with air leak first and test the other possibilities and look at live data to see when you got the repair.
Then you have graduated to being a true technician.
Good luck.
The 1131 code is indicating an over rich appearing condition at the end of a PCM test that fails switching. This sets the specific code.
Best confirmed with a Scanner looking at live data from the sensor in question and compaired to the other side.
.
Secondly, you cannot judge an engine's performance from the plug tips or porcelain color that easily unless your an accomplished expert at it. On a carbed motor yes, on FI motor, no.
Reason is the OX sensors normally are so precision at controlling loop A/F ratio that the plugs will normally look white in a trouble free engine. This is why plug heat range is important in a FI motor.
For the 1131 code you could have one or more of the following; an air leak, short to power in the harness, water in the connector, corrosion in terminals, excessive fuel pressure, low fuel pressure, and a bunch of other possibilities that affect the fuel or air.
So you see it's not that easy. The PCM does this test and found an issue.
Best you can do is go with air leak first and test the other possibilities and look at live data to see when you got the repair.
Then you have graduated to being a true technician.
Good luck.
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New User
Joined: Sep 2013
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You need some instruction on this as follows;
The 1131 code is indicating an over rich appearing condition at the end of a PCM test that fails switching. This sets the specific code.
Best confirmed with a Scanner looking at live data from the sensor in question and compaired to the other side.
.
Secondly, you cannot judge an engine's performance from the plug tips or porcelain color that easily unless your an accomplished expert at it. On a carbed motor yes, on FI motor, no.
Reason is the OX sensors normally are so precision at controlling loop A/F ratio that the plugs will normally look white in a trouble free engine. This is why plug heat range is important in a FI motor.
For the 1132 code you could have one or more of the following; an air leak, short to power in the harness, water in the connector, corrosion in terminals, excessive fuel pressure, low fuel pressure, and a bunch of other possibilities that affect the fuel or air.
So you see it's not that easy. The PCM does this test and found an issue.
Best you can do is go with air leak first and test the other possibilities and look at live data to see when you got the repair.
Then you have graduated to being a true technician.
Good luck.
The 1131 code is indicating an over rich appearing condition at the end of a PCM test that fails switching. This sets the specific code.
Best confirmed with a Scanner looking at live data from the sensor in question and compaired to the other side.
.
Secondly, you cannot judge an engine's performance from the plug tips or porcelain color that easily unless your an accomplished expert at it. On a carbed motor yes, on FI motor, no.
Reason is the OX sensors normally are so precision at controlling loop A/F ratio that the plugs will normally look white in a trouble free engine. This is why plug heat range is important in a FI motor.
For the 1132 code you could have one or more of the following; an air leak, short to power in the harness, water in the connector, corrosion in terminals, excessive fuel pressure, low fuel pressure, and a bunch of other possibilities that affect the fuel or air.
So you see it's not that easy. The PCM does this test and found an issue.
Best you can do is go with air leak first and test the other possibilities and look at live data to see when you got the repair.
Then you have graduated to being a true technician.
Good luck.
Maybe your off for I'm off not sure or I'm misreading ur meaning lol? P1131 doesn't mean it's running rich it means it's running lean?
Lead Driver
Joined: Sep 2006
Posts: 7,907
Likes: 143
The 1131 is telling you the system is trying to correct for a perceived over rich condition.
The system shifts the fuel tables 'lean' trying to correct for it. It is not telling you there is a lean condition from just the code. It is however telling you the fuel table is what has been shifted lean. This is not hardware but software.
The program does not know anything about a leak or any other issue but the end results of it in program as seen by the OX senor sensing exhaust gas..
This is where you mis interpret the end result of the code.
The Ox sensor is no longer able to 'switch' when the table is so far out of limits. There is nothing to switch for under these conditions since there is no longer any way to control fuel.
You see both an air leak and an excess in fuel can cause the same end result. Just depends on how it is happening.
Doubt it, see Ford code descriptions.
You came for help, I'm offering it to you with explanation you won't get anywhere else..
Good luck.
The system shifts the fuel tables 'lean' trying to correct for it. It is not telling you there is a lean condition from just the code. It is however telling you the fuel table is what has been shifted lean. This is not hardware but software.
The program does not know anything about a leak or any other issue but the end results of it in program as seen by the OX senor sensing exhaust gas..
This is where you mis interpret the end result of the code.
The Ox sensor is no longer able to 'switch' when the table is so far out of limits. There is nothing to switch for under these conditions since there is no longer any way to control fuel.
You see both an air leak and an excess in fuel can cause the same end result. Just depends on how it is happening.
Doubt it, see Ford code descriptions.
You came for help, I'm offering it to you with explanation you won't get anywhere else..
Good luck.
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New User
Joined: Sep 2013
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The 1131 is telling you the system is trying to correct for a perceived over rich condition.
The system shifts the fuel tables 'lean' trying to correct for it. It is not telling you there is a lean condition from just the code. It is however telling you the fuel table is what has been shifted lean. This is not hardware but software.
The program does not know anything about a leak or any other issue but the end results of it in program as seen by the OX senor sensing exhaust gas..
This is where you mis interpret the end result of the code.
The Ox sensor is no longer able to 'switch' when the table is so far out of limits. There is nothing to switch for under these conditions since there is no longer any way to control fuel.
You see both an air leak and an excess in fuel can cause the same end result. Just depends on how it is happening.
Doubt it, see Ford code descriptions.
You came for help, I'm offering it to you with explanation you won't get anywhere else..
Good luck.
The system shifts the fuel tables 'lean' trying to correct for it. It is not telling you there is a lean condition from just the code. It is however telling you the fuel table is what has been shifted lean. This is not hardware but software.
The program does not know anything about a leak or any other issue but the end results of it in program as seen by the OX senor sensing exhaust gas..
This is where you mis interpret the end result of the code.
The Ox sensor is no longer able to 'switch' when the table is so far out of limits. There is nothing to switch for under these conditions since there is no longer any way to control fuel.
You see both an air leak and an excess in fuel can cause the same end result. Just depends on how it is happening.
Doubt it, see Ford code descriptions.
You came for help, I'm offering it to you with explanation you won't get anywhere else..
Good luck.
New User
Joined: Jan 2015
Posts: 7
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I have a 1998 Expedition 5.4L Eddie Bauer 4X4. I've been getting all kinds of codes telling me bank 1 and bank 2 too lean and bad upstream O2 sensors. I've changed BOTH upstream O2 sensors on bank 1 and on bank 2. I've fixes all the holes in my PCV vacuum lines by replacing ALL the lines. What's my end result? Engine still runs a tad rough and wants to shut down at intersections and all my codes are gone but P1131. Now what?
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Not sure my man!! I've had the same issue, my p1131 keeps going on and off? I've looked for leaks but seems to dissapear in cold weather sometimes?
I have a 1998 Expedition 5.4L Eddie Bauer 4X4. I've been getting all kinds of codes telling me bank 1 and bank 2 too lean and bad upstream O2 sensors. I've changed BOTH upstream O2 sensors on bank 1 and on bank 2. I've fixes all the holes in my PCV vacuum lines by replacing ALL the lines. What's my end result? Engine still runs a tad rough and wants to shut down at intersections and all my codes are gone but P1131. Now what?
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Lead Driver
Joined: Sep 2006
Posts: 7,907
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Lets try this again;
Code 1131 is telling you there is a rich,-- rich,--rich, condition.
The computer leans,---leans-- leans the fuel table trying to account for the rich condition thus setting the code 1131..
The opposite of rich is lean. The fuel tables move in opposite directions for lean and rich conditions detected by the OX sensors
The OX sensors are not the cause but only report the condition because there is no other way but a CEL and code to alert the driver unless a Scanner were used to look at the tables if you knew there was a problem.
This condition usually is not an air leak.
Look for any cause of excess fuel.
A. Fuel pressure too high. Faulty regulator, blocked return line.
B. Fuel regulator diaphragm leaking fuel into the intake.
C. Leaking injector.
D. Possible cylinder head temp sensor causing a reading for to much fuel that could be season sensitive, if marginal.
E. Thermostat too cold or stuck partially open causing the same condition as D.
Good luck.
Code 1131 is telling you there is a rich,-- rich,--rich, condition.
The computer leans,---leans-- leans the fuel table trying to account for the rich condition thus setting the code 1131..
The opposite of rich is lean. The fuel tables move in opposite directions for lean and rich conditions detected by the OX sensors
The OX sensors are not the cause but only report the condition because there is no other way but a CEL and code to alert the driver unless a Scanner were used to look at the tables if you knew there was a problem.
This condition usually is not an air leak.
Look for any cause of excess fuel.
A. Fuel pressure too high. Faulty regulator, blocked return line.
B. Fuel regulator diaphragm leaking fuel into the intake.
C. Leaking injector.
D. Possible cylinder head temp sensor causing a reading for to much fuel that could be season sensitive, if marginal.
E. Thermostat too cold or stuck partially open causing the same condition as D.
Good luck.
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Gotta love the snottyness with no remedy for correction 
, thanks Ive read those a thousand times on fords website,now perhaps you can be helpful and give instructions on how to test for failure on A-E or should one just start replacing parts lol?
, thanks Ive read those a thousand times on fords website,now perhaps you can be helpful and give instructions on how to test for failure on A-E or should one just start replacing parts lol?Lets try this again;
Code 1131 is telling you there is a rich,-- rich,--rich, condition.
The computer leans,---leans-- leans the fuel table trying to account for the rich condition thus setting the code 1131..
The opposite of rich is lean. The fuel tables move in opposite directions for lean and rich conditions detected by the OX sensors
The OX sensors are not the cause but only report the condition because there is no other way but a CEL and code to alert the driver unless a Scanner were used to look at the tables if you knew there was a problem.
This condition usually is not an air leak.
Look for any cause of excess fuel.
A. Fuel pressure too high. Faulty regulator, blocked return line.
B. Fuel regulator diaphragm leaking fuel into the intake.
C. Leaking injector.
D. Possible cylinder head temp sensor causing a reading for to much fuel that could be season sensitive, if marginal.
E. Thermostat too cold or stuck partially open causing the same condition as D.
Good luck.
Code 1131 is telling you there is a rich,-- rich,--rich, condition.
The computer leans,---leans-- leans the fuel table trying to account for the rich condition thus setting the code 1131..
The opposite of rich is lean. The fuel tables move in opposite directions for lean and rich conditions detected by the OX sensors
The OX sensors are not the cause but only report the condition because there is no other way but a CEL and code to alert the driver unless a Scanner were used to look at the tables if you knew there was a problem.
This condition usually is not an air leak.
Look for any cause of excess fuel.
A. Fuel pressure too high. Faulty regulator, blocked return line.
B. Fuel regulator diaphragm leaking fuel into the intake.
C. Leaking injector.
D. Possible cylinder head temp sensor causing a reading for to much fuel that could be season sensitive, if marginal.
E. Thermostat too cold or stuck partially open causing the same condition as D.
Good luck.
Logistics Pro
Joined: Jan 2001
Posts: 3,740
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From: Central NYS
Look for any cause of excess fuel.
A. Fuel pressure too high. Faulty regulator, blocked return line.
B. Fuel regulator diaphragm leaking fuel into the intake.
C. Leaking injector.
D. Possible cylinder head temp sensor causing a reading for to much fuel that could be season sensitive, if marginal.
E. Thermostat too cold or stuck partially open causing the same condition as D.
Good luck.
A. Fuel pressure too high. Faulty regulator, blocked return line.
B. Fuel regulator diaphragm leaking fuel into the intake.
C. Leaking injector.
D. Possible cylinder head temp sensor causing a reading for to much fuel that could be season sensitive, if marginal.
E. Thermostat too cold or stuck partially open causing the same condition as D.
Good luck.
A. What is your fuel pressure?
B. Is there fuel in the fuel regulator diaphragm?
C. Does the fuel pressure gauge indicate a leak?
D. What is your cyl head temp sensor reading?
E. What is the coolant temp sensor reading?
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For all those looking to correct this and everyone is telling you it's not the sensor the sensor is just providing a reading, finally broke down and brought the truck into my Mechanic and bank one sensor one isn't reading shiat!! So it's the sensor lol after all this looking for this and that it's the sensor lol!!!!
Lets try this again;
Code 1131 is telling you there is a rich,-- rich,--rich, condition.
The computer leans,---leans-- leans the fuel table trying to account for the rich condition thus setting the code 1131..
The opposite of rich is lean. The fuel tables move in opposite directions for lean and rich conditions detected by the OX sensors
The OX sensors are not the cause but only report the condition because there is no other way but a CEL and code to alert the driver unless a Scanner were used to look at the tables if you knew there was a problem.
This condition usually is not an air leak.
Look for any cause of excess fuel.
A. Fuel pressure too high. Faulty regulator, blocked return line.
B. Fuel regulator diaphragm leaking fuel into the intake.
C. Leaking injector.
D. Possible cylinder head temp sensor causing a reading for to much fuel that could be season sensitive, if marginal.
E. Thermostat too cold or stuck partially open causing the same condition as D.
Good luck.
Code 1131 is telling you there is a rich,-- rich,--rich, condition.
The computer leans,---leans-- leans the fuel table trying to account for the rich condition thus setting the code 1131..
The opposite of rich is lean. The fuel tables move in opposite directions for lean and rich conditions detected by the OX sensors
The OX sensors are not the cause but only report the condition because there is no other way but a CEL and code to alert the driver unless a Scanner were used to look at the tables if you knew there was a problem.
This condition usually is not an air leak.
Look for any cause of excess fuel.
A. Fuel pressure too high. Faulty regulator, blocked return line.
B. Fuel regulator diaphragm leaking fuel into the intake.
C. Leaking injector.
D. Possible cylinder head temp sensor causing a reading for to much fuel that could be season sensitive, if marginal.
E. Thermostat too cold or stuck partially open causing the same condition as D.
Good luck.
Lead Driver
Joined: Sep 2006
Posts: 7,907
Likes: 143
Well you took exception to my help. I told you someone needed to search for the issue because there are to many possible causes. In the absence of a working sensor, the computer substitutes a 'fixed' fuel table that is set rich to protect the motor by design. Glad you got it repaired. Good luck.
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