As the title says. I scanned my comp. today and got these codes.(KOEO) The ACT sensor is new, i put 2 new ones on. What would cause a greater signal than the 4.6v of the self-test. And the 32 (the volts less than 0.24v) Any ideas or have you had these also and how did you fix. Could any of these codes cause the engine to run HOT.
Code Scan =54,54,1,32,54,32,54
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powertrax91
Founding Member
silly question but did you get your engine up to operating temps first? I know my puter spews all sorts of sick codes untill I get it up to temp. As for your ACT sensor being stuck open..... I am not sure what to tell you other than to test the sensor if the reading is bad waranty it for a new one. If you still get the same reading i would start looking at the computer as my next suspect.
The symptoms you describe are characteristic of bad wiring or bad connections. If you are not good with electrical stuff, find a bud that is. If electrical circuits are your thing, this will not be hard.
Code 54 – ACT sensor out of range. Broken or damaged wiring, bad ACT sensor. Note that that if the outside air temp is below 50 degrees F that the test for the ACT can be in error.
ACT & ECT test data:
The ACT & ECT have the same thermistor, so the table values are the same
Pin 7 on the computer - ECT signal in. at 176 degrees F it should be .80 volts
Pin 25 on the computer - ACT signal in. at 50 degrees F it should be 3.5 volts. It is a good number if the ACT is mounted in the inlet air box. If it is mounted in the lower intake manifold, the voltage readings will be lower because of the heat transfer. Here's the table:
68 degrees F = 3.02 v
86 degrees F = 2.62 v
104 degrees F = 2.16 v
122 degrees F = 1.72 v
140 degrees F = 1.35 v
158 degrees F = 1.04 v
176 degrees F = .80 v
194 degrees F = .61
Ohms measures at the computer with the computer disconnected, or at the sensor with the sensor disconnected.
50 degrees F = 58.75 K ohms
68 degrees F = 37.30 K ohms
86 degrees F = 27.27 K ohms
104 degrees F = 16.15 K ohms
122 degrees F = 10.97 K ohms
140 degrees F = 7.60 K ohms
158 degrees F = 5.37 K ohms
176 degrees F = 3.84 K ohms
194 degrees F = 2.80 K ohms
If all the resistance readings are good, get out your ohmmeter and check the continuity between the black wire on the ACT sensor and pin 46 on the computer, and the Lt Green/Pink wire & pin 25 on the computer. You should see less than 1 ohm. Remember that a circuit must be powered down to check resistance.
CODE: 32 (KOEO) - EVP circuit below minimum voltage. Vref missing or broken wire or bad contact in circuit. Check for 5 volts on the orange/white wire. With the sensor removed from the EGR and still connected, press the plunger and watch the voltage change on the brown/lt green wire. Check for the same results on pin 27 on the computer. Check for continuity between the wiring at the sensor and the computer. The brown/lt green wire on the sensor & pin 27 should be less than 1 ohm. The black/white wire on the sensor & pin 46 should be less than 1 ohm. The orange/white wire on the sensor & pin 26 should be less than 1 ohm.
See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host)
Computer & sensor wiring diagram - http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif
Code 54 – ACT sensor out of range. Broken or damaged wiring, bad ACT sensor. Note that that if the outside air temp is below 50 degrees F that the test for the ACT can be in error.
ACT & ECT test data:
The ACT & ECT have the same thermistor, so the table values are the same
Pin 7 on the computer - ECT signal in. at 176 degrees F it should be .80 volts
Pin 25 on the computer - ACT signal in. at 50 degrees F it should be 3.5 volts. It is a good number if the ACT is mounted in the inlet air box. If it is mounted in the lower intake manifold, the voltage readings will be lower because of the heat transfer. Here's the table:
68 degrees F = 3.02 v
86 degrees F = 2.62 v
104 degrees F = 2.16 v
122 degrees F = 1.72 v
140 degrees F = 1.35 v
158 degrees F = 1.04 v
176 degrees F = .80 v
194 degrees F = .61
Ohms measures at the computer with the computer disconnected, or at the sensor with the sensor disconnected.
50 degrees F = 58.75 K ohms
68 degrees F = 37.30 K ohms
86 degrees F = 27.27 K ohms
104 degrees F = 16.15 K ohms
122 degrees F = 10.97 K ohms
140 degrees F = 7.60 K ohms
158 degrees F = 5.37 K ohms
176 degrees F = 3.84 K ohms
194 degrees F = 2.80 K ohms
If all the resistance readings are good, get out your ohmmeter and check the continuity between the black wire on the ACT sensor and pin 46 on the computer, and the Lt Green/Pink wire & pin 25 on the computer. You should see less than 1 ohm. Remember that a circuit must be powered down to check resistance.
CODE: 32 (KOEO) - EVP circuit below minimum voltage. Vref missing or broken wire or bad contact in circuit. Check for 5 volts on the orange/white wire. With the sensor removed from the EGR and still connected, press the plunger and watch the voltage change on the brown/lt green wire. Check for the same results on pin 27 on the computer. Check for continuity between the wiring at the sensor and the computer. The brown/lt green wire on the sensor & pin 27 should be less than 1 ohm. The black/white wire on the sensor & pin 46 should be less than 1 ohm. The orange/white wire on the sensor & pin 26 should be less than 1 ohm.
See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host)
Computer & sensor wiring diagram - http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif
You may have wiring problems that cause the stock temp gauge to indicate higher than normal readings. Check all the engine to chassis grounds.
As a side line, here's some ground information that I would work on while troubleshooting your problem.
Grounds are important to any electrical system, and especially to computers.
1.) The main power ground is from engine block to battery: it is the power ground for the starter & alternator.
2.) The secondary power ground is between the back of the intake manifold and the driver's side firewall. It is often missing or loose. It supplies ground for the A/C compressor clutch and other electrical accessories such as the gauges. Any car that has a 3G alternator needs a 4 gauge ground wire running from the block to the chassis ground where the battery pigtail ground connects.
3.) The computer has its own dedicated power ground that comes off the ground pigtail on the battery ground wire. Due to it's proximity to the battery, it may become corroded by acid fumes from the battery.
4.) All the sensors have a common separate ground. This includes the TPS, ACT, EGE, BAP, & VSS
5.) The O2 sensor heaters have their own ground (HEGO ground) coming from the computer. This is different and separate from the O2 sensor ground.
6.) The TFI module has 2 grounds: one for the foil shield around the wires and another for the module itself.
7.) The computer takes the shield ground for the TFI module and runs it from pin 20 to the chassis near the computer.
8.) The computer's main power ground (the one that comes from the battery ground wire) uses pins 40 & 60 for all the things it controls internally.
As a side line, here's some ground information that I would work on while troubleshooting your problem.
Grounds are important to any electrical system, and especially to computers.
1.) The main power ground is from engine block to battery: it is the power ground for the starter & alternator.
2.) The secondary power ground is between the back of the intake manifold and the driver's side firewall. It is often missing or loose. It supplies ground for the A/C compressor clutch and other electrical accessories such as the gauges. Any car that has a 3G alternator needs a 4 gauge ground wire running from the block to the chassis ground where the battery pigtail ground connects.
3.) The computer has its own dedicated power ground that comes off the ground pigtail on the battery ground wire. Due to it's proximity to the battery, it may become corroded by acid fumes from the battery.
4.) All the sensors have a common separate ground. This includes the TPS, ACT, EGE, BAP, & VSS
5.) The O2 sensor heaters have their own ground (HEGO ground) coming from the computer. This is different and separate from the O2 sensor ground.
6.) The TFI module has 2 grounds: one for the foil shield around the wires and another for the module itself.
7.) The computer takes the shield ground for the TFI module and runs it from pin 20 to the chassis near the computer.
8.) The computer's main power ground (the one that comes from the battery ground wire) uses pins 40 & 60 for all the things it controls internally.
Its funny about the "Checking grounds" thing. I just finished checking all grounds and cleaned a few conn. Got the car to 195 and scanned it again. This time i got 54-31-66 so i will reference 31, i know the rest. I am using Autometer Elec. gauges now. My car car sit and idle @180-195 for an hour(thats all i did it for) as soon as i start driving the temps. go to 230-250. I have a miss. i can feel it, i know i HAVE to get it chipped/dyno'd but i would like to take care of these/some issues beforehand.
I was wrong about the 66 i thought it was smog related. It was MAF. I did the test KOEO and when i checked the codes it didnt list it under KOEO. Only CM and KOER. Does this mean something? I did diss. conn. the mass air while it was running and it stalled. And i also diss. conn. the IAB while running and the idle dropped(I WAS TESTING SOME THINGS)
Code 66 MAF below minimum test voltage.
Insufficient or no voltage from MAF. Dirty MAF element, bad MAF, bad MAF wiring, missing power to MAF. Check for missing +12 volts on this circuit. Check the two links for a wiring diagram to help you find the red wire for computer power relay switched +12 volts. Check for 12 volts between the red and black wires on the MAF heater (usually pins A & B). while the connector is plugged into the MAF. This may require the use of a couple of safety pins to probe the MAF connector from the back side of it.
There are three parts in a MAF: the heater, the sensor element and the amplifier. The heater heats the MAF sensor element causing the resistance to increase. The amplifier buffers the MAF output signal and has a resistor that is laser trimmed to provide an output range compatible with the computer's load tables.
The MAF output varies with RPM which causes the airflow to increase or decease. The increase of air across the MAF sensor element causes it to cool, allowing more voltage to pass and telling the computer to increase the fuel flow. A decrease in airflow causes the MAF sensor element to get warmer, decreasing the voltage and reducing the fuel flow. Measure the MAF output at pins C & D on the MAF connector (dark blue/orange and tan/light blue) or at pins 50 & 9 on the computer.
At idle = approximately .6 volt
20 MPH = approximately 1.10 volt
40 MPH = approximately 1.70 volt
60 MPH = approximately 2.10 volt
Check the resistance of the MAF signal wiring. Pin D on the MAF and pin 50 on the computer (dark blue/orange wire) should be less than 2 ohms. Pin C on the MAF and pin 9 on the computer (tan/light blue wire) should be less than 2 ohms.
There should be a minimum of 10K ohms between either pin C or D on the MAF and ground.
See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host)
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif
http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif
To clean the MAF, remove the MAF element and gently spray it with electrical contact cleaner. You can also use non-flammable brake parts cleaner (same chemical in a bigger can & cheaper too). Let it dry and put it back in.
Insufficient or no voltage from MAF. Dirty MAF element, bad MAF, bad MAF wiring, missing power to MAF. Check for missing +12 volts on this circuit. Check the two links for a wiring diagram to help you find the red wire for computer power relay switched +12 volts. Check for 12 volts between the red and black wires on the MAF heater (usually pins A & B). while the connector is plugged into the MAF. This may require the use of a couple of safety pins to probe the MAF connector from the back side of it.
There are three parts in a MAF: the heater, the sensor element and the amplifier. The heater heats the MAF sensor element causing the resistance to increase. The amplifier buffers the MAF output signal and has a resistor that is laser trimmed to provide an output range compatible with the computer's load tables.
The MAF output varies with RPM which causes the airflow to increase or decease. The increase of air across the MAF sensor element causes it to cool, allowing more voltage to pass and telling the computer to increase the fuel flow. A decrease in airflow causes the MAF sensor element to get warmer, decreasing the voltage and reducing the fuel flow. Measure the MAF output at pins C & D on the MAF connector (dark blue/orange and tan/light blue) or at pins 50 & 9 on the computer.
At idle = approximately .6 volt
20 MPH = approximately 1.10 volt
40 MPH = approximately 1.70 volt
60 MPH = approximately 2.10 volt
Check the resistance of the MAF signal wiring. Pin D on the MAF and pin 50 on the computer (dark blue/orange wire) should be less than 2 ohms. Pin C on the MAF and pin 9 on the computer (tan/light blue wire) should be less than 2 ohms.
There should be a minimum of 10K ohms between either pin C or D on the MAF and ground.
See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host)
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif
http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif
To clean the MAF, remove the MAF element and gently spray it with electrical contact cleaner. You can also use non-flammable brake parts cleaner (same chemical in a bigger can & cheaper too). Let it dry and put it back in.
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