My computer codes
- Thread starter SHOdownTN
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rangerj
Active Member
The sensors transmit a signal to the computer that is usually either in volts or ohms resistance. The computer is programmed to expect a specific signal, or a range, that depends on a specific set of circumstances, say for example a voltage range that depends upon temperature (coolant temperature sensor).
In doing the diagnostics for each "fault code" you want to determine if the sensor is bad, or if it is a poor connection, or a broken or shorted wire causing the problem.
Start the process by disconnecting the sensor and inspect both the sensor and the wire connectors (pins or spades). Is it a good clean connection and free of corrosion? Are any pins broken, bent, or loose? If the connection is not good, clean it, correct the problem, and reconnect it. Clear your codes and see if the code returns.
Next, you want to test the signals to the sensor and the signal back to the computer. This will confirm that the computer is sending the signal (say voltage) to the sensor, and if there is a signal going out to the computer, and what the range of the signal is (if it is within the specified range).
For example lets look at the temperature sensor[engine coolant] (not the temperature "sending unit" that activates the gauge).
Disconnect the sensor and measure the ohms resistance between the sensors terminal (pins). If the engine is cold the resistance will be high, eg at 50 degrees F the resistance should be 58.75K ohms + or - 15% variation.
KOEO with the sensor connected. Backprobe the sensor terminals. the voltage coming out of the sensor in a cold engine of 50 degrees F should be approximately 3.52 to 4.25 volts (again with some slight variation). As the temperature goes up the voltage should drop.
A fully warmed up engine, say 220 F, should show approximately .35 to .40 volts. (Note: the voltage being sent to the sensor is approximately 5 to 8 volts [V-Ref]) The out going voltage will vary depending on the temperature of the sensor (say from .3 V to less than 5 V).
If the sensor is not getting a voltage signal (o volts) then there is a broken or shorted wire, or a poor connection, between the computer and the sensor. If the sensor is putting out the correct signal, and the computer says it is not, then look for a broken or shorted wire or a poor connection between the sensor and the computer. If the sensor is not putting out the correct signal (range), then replace the sensor.
The above tests are done with a digital multi-meter, NOT an analog (swing needle) meter. Further, DO NOT probe these systems with an incandescent style probe. Use a LED light type probe.
There is a short cut to the above if you know that the sensors are original, ie OLD. Say for example the O2 sensor has 50K on it. Change it. The recommended change interval is 60K, so the odds are the sensor is bad. Check the connections first, and if they are OK, then change the sensor. This is basically an educated guess based upon experience and the "ODDS".
Check the EGR valve visually. Is the valve poppet stem moving when the throttle is moved? You can also check the EGR with a vacuum pump. If the valve is phisically working, then check the connections (vacuum and/or electric). There is an EGR valve position sensor (EVP), an EGR pressure transducer (EPT), an EGR vacuum regulator (EVR), and an EGR control vacuum solenoid. Then there is the DPFE (differential pressure feedback EGR - which is the afformentioned system as a whole).
Check your vacuum and electrical connections on the EGR system, and check the valve itself. Also check the tubing that transmits the exaust gas from the exaust to the EGR valve, which then lets it go into the intake manifold. If that does not lead you to the fault get back to us.
The above should get you started. Any questions? Just ask.
rangerj
In doing the diagnostics for each "fault code" you want to determine if the sensor is bad, or if it is a poor connection, or a broken or shorted wire causing the problem.
Start the process by disconnecting the sensor and inspect both the sensor and the wire connectors (pins or spades). Is it a good clean connection and free of corrosion? Are any pins broken, bent, or loose? If the connection is not good, clean it, correct the problem, and reconnect it. Clear your codes and see if the code returns.
Next, you want to test the signals to the sensor and the signal back to the computer. This will confirm that the computer is sending the signal (say voltage) to the sensor, and if there is a signal going out to the computer, and what the range of the signal is (if it is within the specified range).
For example lets look at the temperature sensor[engine coolant] (not the temperature "sending unit" that activates the gauge).
Disconnect the sensor and measure the ohms resistance between the sensors terminal (pins). If the engine is cold the resistance will be high, eg at 50 degrees F the resistance should be 58.75K ohms + or - 15% variation.
KOEO with the sensor connected. Backprobe the sensor terminals. the voltage coming out of the sensor in a cold engine of 50 degrees F should be approximately 3.52 to 4.25 volts (again with some slight variation). As the temperature goes up the voltage should drop.
A fully warmed up engine, say 220 F, should show approximately .35 to .40 volts. (Note: the voltage being sent to the sensor is approximately 5 to 8 volts [V-Ref]) The out going voltage will vary depending on the temperature of the sensor (say from .3 V to less than 5 V).
If the sensor is not getting a voltage signal (o volts) then there is a broken or shorted wire, or a poor connection, between the computer and the sensor. If the sensor is putting out the correct signal, and the computer says it is not, then look for a broken or shorted wire or a poor connection between the sensor and the computer. If the sensor is not putting out the correct signal (range), then replace the sensor.
The above tests are done with a digital multi-meter, NOT an analog (swing needle) meter. Further, DO NOT probe these systems with an incandescent style probe. Use a LED light type probe.
There is a short cut to the above if you know that the sensors are original, ie OLD. Say for example the O2 sensor has 50K on it. Change it. The recommended change interval is 60K, so the odds are the sensor is bad. Check the connections first, and if they are OK, then change the sensor. This is basically an educated guess based upon experience and the "ODDS".
Check the EGR valve visually. Is the valve poppet stem moving when the throttle is moved? You can also check the EGR with a vacuum pump. If the valve is phisically working, then check the connections (vacuum and/or electric). There is an EGR valve position sensor (EVP), an EGR pressure transducer (EPT), an EGR vacuum regulator (EVR), and an EGR control vacuum solenoid. Then there is the DPFE (differential pressure feedback EGR - which is the afformentioned system as a whole).
Check your vacuum and electrical connections on the EGR system, and check the valve itself. Also check the tubing that transmits the exaust gas from the exaust to the EGR valve, which then lets it go into the intake manifold. If that does not lead you to the fault get back to us.
The above should get you started. Any questions? Just ask.
rangerj
I can't tell that my egr valve is moveing. Also I pulled the vacume line off of the diaphram and put my finger over the line to see if it was getting vacume with the car running of course. I get a little hint of vacume and feels more like a pulse. I really need a vacume test somehow.
The problem is I have put the egr on just a few months back. I really don't wanna change it but will if I have too......
The problem is I have put the egr on just a few months back. I really don't wanna change it but will if I have too......
rangerj
Active Member
Oh boy, you know not what you ask!
OK, You replaced the EGR VALVE. Is that correct? Understand that when the car is cold the EGR system is shut down, i.e. is not activated. It is also shut down at wide open throttle, and at idle. Ergo if you were looking to see if the poppet valve stem move under any of these conditions, it would not move.
Next item. What year is your SHO and what engine is in it. What I really need to know is whether you have the PFE or DPFE system. PFE is "pressure feedback" and "Delta PFE" uses the "Delta", or difference in pressure, slightly different. I think DPFE started with the 92 model year. I'm checking my reference sources now.
Anyways, while I'm looking into the test procedures for the EGR SYSTEM you can make sure the vacuum hose to the PFE or DPFE (depending on your model year) is not blocked, nor cracked or broken (leaking vacuum).
We will see if we can sort this out. You can also help by looking at a shop manual and make sure you know what the parts of the system are and where they are located. If you do not own a shop manual go to the local library, or try the Auto Zone web site for their repair manuals on line.
It will help a great deal if you know what I am talking about when I ask you to test a connection or the sensor pins, or to apply vacuum, etc.
rangerj
OK, You replaced the EGR VALVE. Is that correct? Understand that when the car is cold the EGR system is shut down, i.e. is not activated. It is also shut down at wide open throttle, and at idle. Ergo if you were looking to see if the poppet valve stem move under any of these conditions, it would not move.
Next item. What year is your SHO and what engine is in it. What I really need to know is whether you have the PFE or DPFE system. PFE is "pressure feedback" and "Delta PFE" uses the "Delta", or difference in pressure, slightly different. I think DPFE started with the 92 model year. I'm checking my reference sources now.
Anyways, while I'm looking into the test procedures for the EGR SYSTEM you can make sure the vacuum hose to the PFE or DPFE (depending on your model year) is not blocked, nor cracked or broken (leaking vacuum).
We will see if we can sort this out. You can also help by looking at a shop manual and make sure you know what the parts of the system are and where they are located. If you do not own a shop manual go to the local library, or try the Auto Zone web site for their repair manuals on line.
It will help a great deal if you know what I am talking about when I ask you to test a connection or the sensor pins, or to apply vacuum, etc.
rangerj
Sorry Fuel injected is all new to me. I never had to work on one before. My car before this one was a carburated 87 Mustang. I had a 86 that was injected but never had to mess with it and a 89 Mazda truck which was the same with the Mustang. I wouldn't even be trying to do this if not for the CE light comeing on.rangerj said:
Anyways on to the important stuff. My car is a 93 ATX. I have some repair manuals but they are only the Chiltons big book and one on the regular taurus. AutoZone has online repair manuals? i'll go look for it and get it put in my favorites.
LMAO, well I replaced both O2's and replaced the ECT so now I know they are good. Now the CE light still comes on. I'm assuming still something to do with the EGR.
Could the EGR sensor be dirty or clogged or something causeing it not to read. I have checked all connections and all is well. Last thing is to do the vacume test on the egr valve it's self but I wont have the tool till this Friday. I know I could have probly bought one somewhere but I may need it more times down the road so I got one from SnapOn.
Now I need to know what to look for when I check the EGR valve. Pressure drop? no movement?
Could the EGR sensor be dirty or clogged or something causeing it not to read. I have checked all connections and all is well. Last thing is to do the vacume test on the egr valve it's self but I wont have the tool till this Friday. I know I could have probly bought one somewhere but I may need it more times down the road so I got one from SnapOn.
Now I need to know what to look for when I check the EGR valve. Pressure drop? no movement?
rangerj
Active Member
Before you do anything else erase (clear) the codes. Then drive the car and see what codes come back. See the search feature regarding clearing the codes if you do not know how. Basically you disconnect before you finish checking the codes.
Back near the EGR valve there should be a EGR Vacuum Regulator (EVR). Follow the hose from the EGR to the source. The EVR has a second vacuum hose that goes to a source of vacuum (It may be directly or indirectly attached to the intake manifold). Make sure these hoses are not blocked or leaking vacuum, say due to cracks or a break in a line. Vacuum hoses will often crack where they are attached at the ******.
Once you find the EVR it should have a connector with a BR/PK (brown/pink stripe) wire, and a RED wire attached to it. The BR/PK is the VPR signal wire (to the computer) and the red wire is the VPWR (battery voltage) wire.
With the key off for at least 10 seconds (wait a minute) unplug the EVR connector. Use a multi meter to measure resistance across the two pins in the EVR sensor. You should get a reading of approximately 20 to 70 ohms. If you get more or less resistance the sensor may be faulty. However, do the next test before replacing the sensor.
With the KOEO (Key on Engine OFF) measure the voltage at the VPWR pin in the CONNECTOR when grounded to the battery negative terminal. Repeat, the positive probe of the meter goes to the connector pin attached to the red wire, and the negative probe goes to the negative battery terminal. You should get greater than10.5 volts (Approximately battery voltage).
If you get the correct voltage being supplied to the sensor, and the sensor reading is less than, or more than, the prescribed ohms resistance, replace the sensor.
When you are done with this let me know and we will go on from there if the problem is not resolved.
Also make sure the EGR tube is not plugged up, nor cracked, or broken. Also make sure that the manifold where the EGR tube is attached and accepts the Exaust Gas is not blocked. Carbon deposits will build up and block passages in the EGR system, ie the tube, intake manifold, and the valve itself. You valve should be OK because you just replaced it. Have the other parts of the system been checked and cleared?
Note: with your new vacuum tool you should get manifold vacuum off of the hose going into the sensor, about 18 to 20 inches of vacuum at idle. The hose from the sensor to the EGR valve should produce vacuum when the engine is fully warmed up and off of idle. Remember the EGR is not activated when the engine is cold or at idle or WOT. So, tip the throttle a LITTLE and the EGR vacuum line should be activated with vacuum. This should confirm whether the sensor is working or not. It could also tell you if you have a vacuum hose problem.
Get back to me. rangerj
Back near the EGR valve there should be a EGR Vacuum Regulator (EVR). Follow the hose from the EGR to the source. The EVR has a second vacuum hose that goes to a source of vacuum (It may be directly or indirectly attached to the intake manifold). Make sure these hoses are not blocked or leaking vacuum, say due to cracks or a break in a line. Vacuum hoses will often crack where they are attached at the ******.
Once you find the EVR it should have a connector with a BR/PK (brown/pink stripe) wire, and a RED wire attached to it. The BR/PK is the VPR signal wire (to the computer) and the red wire is the VPWR (battery voltage) wire.
With the key off for at least 10 seconds (wait a minute) unplug the EVR connector. Use a multi meter to measure resistance across the two pins in the EVR sensor. You should get a reading of approximately 20 to 70 ohms. If you get more or less resistance the sensor may be faulty. However, do the next test before replacing the sensor.
With the KOEO (Key on Engine OFF) measure the voltage at the VPWR pin in the CONNECTOR when grounded to the battery negative terminal. Repeat, the positive probe of the meter goes to the connector pin attached to the red wire, and the negative probe goes to the negative battery terminal. You should get greater than10.5 volts (Approximately battery voltage).
If you get the correct voltage being supplied to the sensor, and the sensor reading is less than, or more than, the prescribed ohms resistance, replace the sensor.
When you are done with this let me know and we will go on from there if the problem is not resolved.
Also make sure the EGR tube is not plugged up, nor cracked, or broken. Also make sure that the manifold where the EGR tube is attached and accepts the Exaust Gas is not blocked. Carbon deposits will build up and block passages in the EGR system, ie the tube, intake manifold, and the valve itself. You valve should be OK because you just replaced it. Have the other parts of the system been checked and cleared?
Note: with your new vacuum tool you should get manifold vacuum off of the hose going into the sensor, about 18 to 20 inches of vacuum at idle. The hose from the sensor to the EGR valve should produce vacuum when the engine is fully warmed up and off of idle. Remember the EGR is not activated when the engine is cold or at idle or WOT. So, tip the throttle a LITTLE and the EGR vacuum line should be activated with vacuum. This should confirm whether the sensor is working or not. It could also tell you if you have a vacuum hose problem.
Get back to me. rangerj
Ok I will reset the computer and dirve it till the light comes on. Then, read codes again and see what codes I get. Then I will check the sensor to see if it's faulty or not.
It may be this weekend before i can get into checking the tube going to the EGR valve. Also get into checking the rest of the vac lines of the system.
It may be this weekend before i can get into checking the tube going to the EGR valve. Also get into checking the rest of the vac lines of the system.
38SHO
#1 Oil Abuser
oh ya if nobdy mentioned or you don't know...
those KOER codes can be normal, they come from running the test when the car is not up to high normal temperature, nothing to worry about
those KOER codes can be normal, they come from running the test when the car is not up to high normal temperature, nothing to worry about
38SHO
#1 Oil Abuser
those two KOER codes won't set the CE light either
got 18 from the intake side between intake and sensor.SHOdownTN said:I just want the CE light gone.
Anyways, RangerJ. I got my Vacume/pressure tester. I need to know what to do with it and what to look for....(n/m I forgot to look up)The last part of your last post.
About 5 on the other going to the EGR. And This slowly rose to 5 with the engine warm and about 1200 too 1300 rpm. Just a little above idle.
BTW: I checked this useing the T that came with the kit. Just put the T in line then I hooked the gauge to it. Did I hook it up correctly?
Ok, I finally got the light out for good so far.
I did a search on here under the code I got, The 332 code and found that a blockage could also throw this code and that most of the time the nostrils in the intake are stopped up. I found out witch ones to clean and went looking. I looked inside the intake and sure enuff mine were stopped up. I couldn't even get a coat hanger to break it loose. I actually took and cut 3 prongs off of a fork "hardest metal I could find at the time" and finally got it loose with some carb cleaner. Then, went back with the coat hanger and cleaner over and over till no more crud came out.
Took the car for a long test drive. I was out for about 30min. and maybe a toatal of 22mi without any check engine light.
I did a search on here under the code I got, The 332 code and found that a blockage could also throw this code and that most of the time the nostrils in the intake are stopped up. I found out witch ones to clean and went looking. I looked inside the intake and sure enuff mine were stopped up. I couldn't even get a coat hanger to break it loose. I actually took and cut 3 prongs off of a fork "hardest metal I could find at the time" and finally got it loose with some carb cleaner. Then, went back with the coat hanger and cleaner over and over till no more crud came out.
Took the car for a long test drive. I was out for about 30min. and maybe a toatal of 22mi without any check engine light.
rangerj
Active Member
SHODOWNTN,
I love it when a plan comes together! Way to go buddy. Now let's finish up by 1.) clearing the codes, and 2.) checking to see if any codes retrurn.
And yes you can hook up the vacuum gauge by using a "T" connection. If you got a complete vacuum kit along with the pump you will find it usefull for many other repair jobs. I use mine to draw fluid through my brake lines until I get clean fluid. Then I do the "pump the pedal and bleed" routine with my lovely assistant. You can also use it to test the EGR valve and the brake booster. It is a terrific tool to have in your collection.
For all those out there reading this it would be a good idea to check and clean your EGR ports and the tube every couple of years.
rangerj
I love it when a plan comes together! Way to go buddy. Now let's finish up by 1.) clearing the codes, and 2.) checking to see if any codes retrurn.
And yes you can hook up the vacuum gauge by using a "T" connection. If you got a complete vacuum kit along with the pump you will find it usefull for many other repair jobs. I use mine to draw fluid through my brake lines until I get clean fluid. Then I do the "pump the pedal and bleed" routine with my lovely assistant. You can also use it to test the EGR valve and the brake booster. It is a terrific tool to have in your collection.
For all those out there reading this it would be a good idea to check and clean your EGR ports and the tube every couple of years.
rangerjMine didn't come with any pumprangerj said:SHODOWNTN,
I love it when a plan comes together! Way to go buddy. Now let's finish up by 1.) clearing the codes, and 2.) checking to see if any codes retrurn.
And yes you can hook up the vacuum gauge by using a "T" connection. If you got a complete vacuum kit along with the pump you will find it usefull for many other repair jobs. I use mine to draw fluid through my brake lines until I get clean fluid. Then I do the "pump the pedal and bleed" routine with my lovely assistant. You can also use it to test the EGR valve and the brake booster. It is a terrific tool to have in your collection.
For all those out there reading this it would be a good idea to check and clean your EGR ports and the tube every couple of years.
Oh well it does however shov vacume and pressure from a source so even if I can't put vacume on something it will still be usefull. No lights today also went fishing today about 30mi from the house. All's good so far. I cleared the codes but haven't checked them yet. Will do though......On too the EGR ports, if your a real clean freak like me. I will be cleaning mine every oil change or atleast hit them with a few shots of carb cleaner.
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