Check Engine Light??

Foxfirst846

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Ok everyone I found the plug and the harness! Can I just buy a new NSS and plug it in to troubleshoot? I have fat hands and think I have to drop down transmission to actually plug into the transmission the right way..
 
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Foxfirst846

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Jan 24, 2017
88
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Ok everyone I found the plug and the harness! Can I just buy a new NSS and plug it in to troubleshoot? I have fat hands and think I have to drop down transmission to actually plug into the transmission the right way..
 

Mustang5L5

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The connection point is drivers side right above the linkage.

You can see the black plug in this photo

IMG_0709.JPG


For the time being, you can just jump out the harness. I'll have to check my wiring diagrams. Update in a bit
O
Edit: correction. There is a short 1 foot harness that connects the body harness to the trans. I assume what you see dangling is c107

IMG_0711.JPG
 
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Foxfirst846

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I can see it on my car. But I guess I'm just wondering if I can buy a new one to troubleshoot and get rid of that code? Or do I have to drop cross member and lower transmission to actually plug everything in to get rid of code? I can buy a new switch and just return after troubleshooting.


The connection point is drivers side right above the linkage.

You can see the black plug in this photo

IMG_0709.JPG


For the time being, you can just jump out the harness. I'll have to check my wiring diagrams. Update in a bit
 

Mustang5L5

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I'd just jump the wires.

Looks like the two colors for NSS are

White with pink tracer
Red with light blue tracer

Jump those out and try it.

IMG_0713.JPG


The harness does travel to the drivers kick panel by your foot. Should be a black 8-wire plug. Since you have AOD one side will only have 6 wires. Unplug and jump on the 8-wire side
 

Foxfirst846

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Ok guys thank you for all your help! I got rid of code 67!! Now I have more problems.. My code reader says my car is a v6.. I checked vin and engine.. It's a factory v8 car... Has the A9P computer in it.. It's not missing or anything. Pretty sure I'd be able to tell if two cylinders were missing.. So why would the code scanner say it's a 6 cylinder car?
 

Foxfirst846

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The code reader says to push the test/hold button and the code reader will show how many cylinders the car has 4/6/8 then it'll show you the codes. Well mine said it was a 6 cylinder...

What do you mean the code reader says it's a 6 cyl?
 

Foxfirst846

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I should have mentioned im using an Innova Code Scanner #3145 Ford, Lincoln, Mercury
The book for the scanner says - under step 7

1) Warm up the vehicle
2) Turn ignition off
3) Turn the code reader off, then connect code reader.
4) Turn ignition on and start the engine.
5) Press and release the On/Off button on code reader to turn it on.
6) Put Code Scanner HOLD/TEST
• This starts the KOER (Key On
Engine Running) Self-Test.
• A small square and R is shown to indicate the code being received is a KOER self test fault code.
7) The first code displayed by the code reader is the cylinder identification code which identifies the number of cylinders of the vehicle that is under test...

THIS IS WHERE MINE SAYS 6. Versus 8 like it should...
 

jrichker

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T
I should have mentioned im using an Innova Code Scanner #3145 Ford, Lincoln, Mercury
The book for the scanner says - under step 7

1) Warm up the vehicle
2) Turn ignition off
3) Turn the code reader off, then connect code reader.
4) Turn ignition on and start the engine.
5) Press and release the On/Off button on code reader to turn it on.
6) Put Code Scanner HOLD/TEST
• This starts the KOER (Key On
Engine Running) Self-Test.
• A small square and R is shown to indicate the code being received is a KOER self test fault code.
7) The first code displayed by the code reader is the cylinder identification code which identifies the number of cylinders of the vehicle that is under test...

THIS IS WHERE MINE SAYS 6. Versus 8 like it should...
This is unusual, but not new or novel; I have seen it before.
Just ignore it and proceed on
 

Foxfirst846

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Alright everyone thanks for all your guys help!! I've got the KEOR codes now!! I listed what my book says. But in leymans terms.. Can you guys tell me how to fix these things?

21 probably a fault code (because I didn't let it warm up enough?)
41 HEGO HO2S sensor voltage low/system lean
91 HEGO HO2S sensor voltage low/system lean
35 RPM too low for EGR test OR EVP/PFE voltage high

Thanks for all your guys help!!!
 
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Foxfirst846

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I'm thinking I've got a bad ground on the oxygen sensors and I need to replace at least one of them.. So I guess I'm asking your guys opinions about what to tackle first?

Thank you all again!
 

jrichker

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Code 41 or 91. Or 43 Three digit code 172 or 176 - O2 sensor indicates system lean. Look for a vacuum leak or failing O2 sensor.

Revised 11-Jan-2015 to add check for fuel pressure out of range

Code 41 is the passenger side sensor, as viewed from the driver's seat.
Code 91 is the driver side sensor, as viewed from the driver's seat.

Code 172 is the passenger side sensor as viewed from the driver's seat.
Code 176 is the driver side sensor, as viewed from the driver's seat.

Code 43 is not side specific according to the Probst Ford Fuel injection book.

The computer sees a lean mixture signal coming from the O2 sensors and tries to compensate by adding more fuel. Many times the end result is an engine that runs pig rich and stinks of unburned fuel.

The following is a Quote from Charles O. Probst, Ford fuel Injection & Electronic Engine control:
"When the mixture is lean, the exhaust gas has oxygen, about the same amount as the ambient air. So the sensor will generate less than 400 Millivolts. Remember lean = less voltage.

When the mixture is rich, there's less oxygen in the exhaust than in the ambient air , so voltage is generated between the two sides of the tip. The voltage is greater than 600 millivolts. Remember rich = more voltage.

Here's a tip: the newer the sensor, the more the voltage changes, swinging from as low as 0.1 volt to as much as 0.9 volt. As an oxygen sensor ages, the voltage changes get smaller and slower - the voltage change lags behind the change in exhaust gas oxygen.

Because the oxygen sensor generates its own voltage, never apply voltage and never measure resistance of the sensor circuit. To measure voltage signals, use an analog voltmeter with a high input impedance, at least 10 megohms. Remember, a digital voltmeter will average a changing voltage." End Quote

Testing the O2 sensors 87-93 5.0 Mustangs
Measuring the O2 sensor voltage at the computer will give you a good idea of how well they are working. You'll have to pull the passenger side kick panel off to gain access to the computer connector. Remove the plastic wiring cover to get to the back side of the wiring. Use a safety pin or paper clip to probe the connections from the rear.

Disconnect the O2 sensor from the harness and use the body side O2 sensor harness as the starting point for testing. Do not measure the resistance of the O2 sensor , you may damage it. Resistance measurements for the O2 sensor harness are made with one meter lead on the O2 sensor harness and the other meter lead on the computer wire or pin for the O2 sensor.

Backside view of the computer wiring connector:
a9x-series-computer-connector-wire-side-view-gif.71316.gif


87-90 5.0 Mustangs:
Computer pin 43 Dark blue/Lt green – LH O2 sensor
Computer pin 29 Dark Green/Pink – RH O2 sensor
The computer pins are 29 (L\RH O2 with a dark green/pink wire) and 43 (LH O2 with a dark blue/pink wire). Use the ground next to the computer to ground the voltmeter. The O2 sensor voltage should switch between .2-.9 volt at idle.

91-93 5.0 Mustangs:
Computer pin 43 Red/Black – LH O2 sensor
Computer pin 29 Gray/Lt blue – RH O2 sensor
The computer pins are 29 (LH O2 with a Gray/Lt blue wire) and 43 (RH O2 with a Red/Black wire). Use the ground next to the computer to ground the voltmeter. The O2 sensor voltage should switch between .2-.9 volt at idle.


Testing the O2 sensors 94-95 5.0 Mustangs
Measuring the O2 sensor voltage at the computer will give you a good idea of how well they are working. You'll have to pull the passenger side kick panel off to gain access to the computer connector. Remove the plastic wiring cover to get to the back side of the wiring. Use a safety pin or paper clip to probe the connections from the rear. The computer pins are 29 (LH O2 with a red/black wire) and 27 (RH O2 with a gray/lt blue wire). Use pin 32 (gray/red wire) to ground the voltmeter. The O2 sensor voltage should switch between .2-.9 volt at idle.


Note that all resistance tests must be done with power off. Measuring resistance with a circuit powered on will give false readings and possibly damage the meter. Do not attempt to measure the resistance of the O2 sensors, it may damage them.

Testing the O2 sensor wiring harness
Most of the common multimeters have a resistance scale. Be sure the O2 sensors are disconnected and measure the resistance from the O2 sensor body harness to the pins on the computer. Using the Low Ohms range (usually 200 Ohms) you should see less than 1.5 Ohms.

87-90 5.0 Mustangs:
Computer pin 43 Dark blue/Lt green – LH O2 sensor
Computer pin 29 Dark Green/Pink – RH O2 sensor
Disconnect the connector from the O2 sensor and measure the resistance:
From the Dark blue/Lt green wire in the LH O2 sensor harness and the Dark blue/Lt green wire on the computer pin 43
From the Dark Green/Pink wire on the RH Os sensor harness and the Dark Green/Pink wire on the computer pin 29

91-93 5.0 Mustangs:
Computer pin 43 Red/Black – LH O2 sensor
Computer pin 29 Gray/Lt blue – RH O2 sensor
Disconnect the connector from the O2 sensor and measure the resistance:
From the Red/Black wire in the LH O2 sensor harness and the Red/Black wire on the computer pin 43
From the Dark Green/Pink Gray/Lt blue wire on the RH Os sensor harness and the Gray/Lt blue wire on the computer pin 29

94-95 5.0 Mustangs:
Computer pin 29 Red/Black – LH O2 sensor
Computer pin 27 Gray/Lt blue – RH O2 sensor
From the Red/Black wire in the LH O2 sensor harness and the Red/Black wire on the computer pin 29
From the Dark Green/Pink Gray/Lt blue wire on the RH Os sensor harness and the Gray/Lt blue wire on the computer pin 27

There is a connector between the body harness and the O2 sensor harness. Make sure the connectors are mated together, the contacts and wiring are not damaged and the contacts are clean and not coated with oil.

The O2 sensor ground (orange wire with a ring terminal on it) is in the wiring harness for the fuel injection wiring. I grounded mine to one of the intake manifold bolts

Check the fuel pressure – the fuel pressure is 37-41 PSI with the vacuum disconnected and the engine idling. Fuel pressure out of range can cause the 41 & 91 codes together. It will not cause a single code, only both codes together.

Make sure you have the proper 3 wire O2 sensors. Only the 4 cylinder cars used a 4 wire sensor, which is not compatible with the V8 wiring harness.

Replace the O2 sensors in pairs if replacement is indicated. If one is weak or bad, the other one probably isn't far behind.

Code 41 can also be due to carbon plugging the driver’s side Thermactor air crossover tube on the back of the engine. The tube fills up with carbon and does not pass air to the driver’s side head ports. This puts an excess amount of air in the passenger side exhaust and can set the code 41. Remove the tube and clean it out so that both sides get good airflow: this may be more difficult than it sounds. You need something like a mini rotor-rooter to do the job because of the curves in the tube. Something like the outer spiral jacket of a flexible push-pull cable may be the thing that does the trick.

If you get only code 41 and have changed the sensor, look for vacuum leaks. This is especially true if you are having idle problems. The small plastic tubing is very brittle after many years of the heating it receives. Replace the tubing and check the PVC and the hoses connected to it.
 

Mustang5L5

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Code 35...is your EGR system hooked up? Vacuum line present and running to the regulator on passenger side rear strut tower?
 

Foxfirst846

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I'm pretty sure all the egr valve is hooked up and ran to the correct locations... But I'm not 100% certain.. I'll have to check again in a couple days... Foundout my alternator is bad so that's first so I can keep my battery in good condition!!
 

jrichker

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Code 35 EVR - EVP sensor signal is/was high – Bad sensor, or possible missing ground for EVR circuit. With the power off, measure the resistance between the black/white wire and battery ground. You should see less than 1 ohm. Check the same black /white wire on the TPS and MAP sensor. More than 1 ohm there and the wire is probably broken in the harness between the engine and the computer. The 10 pin connectors pass the black/white wire back to the computer, and can cause problems.

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host)

http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif

See the graphic for the 10 pin connector circuit layout.
?temp_hash=3ef2497fff29a7a9daee955cf93e5805.jpg
 

Foxfirst846

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Alright everyone I know this is an old thread. I finally got around to replacing the O2 sensors!!! Cleared the codes and scanned it again. Now I'm getting..

KOEO 34 and 85 then gives me a 10

34 insufficient EGR flow or EVP voltage high (SONIC) or PFE sensor voltage high or out of specification
85 canister purge solenoid circuit failure WHICH HAS BEEN REMOVED ON MY CAR..
OR 85 Adaptive fuel limit reached -lean

KOER CODES

94 Air diver solenoid circuit fault
44 Thermactor air system fault
35 RPM too low for EGR test OR EVP/PFE voltage high
13 RPM at idle out of range/low

What the h*** do I have going on here?

I know the charcoal canister has been deleted. But I'm not sure about the EVP/PFE system... I just want the stinking check engine light off... Any of these codes affecting performance? Do any of these codes NOT trip the CEL??

Thanks for all the help
 
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