Code 121

[tompumped]

I just performed this test with my breakout box and when performing the test there is an open between both pins 26&57 without the tps unplugged. With the tps plugged in I have an open between 47&57 and the values between 47&26 are 1.572 K ohm.

It only says leave processor disconnected and doesn't mention the tps so i'd imagine it has to be connected for the test. I used to be much better at diagnosing electrical problems. Its either been too long or my brain is fried, i'm disgusted with myself. The throttle position sensor circuit is one of the simplest circuits and my brain is just not working right anymore.

I don't have the time to dive into it during the week and I don't want to waste any time on the weekend. Pointers would be much appreciated. The car will not rev past 6k and there are no other codes.

I tried swapping a tps and computer before I took out the BOB, only because I had known good ones. I could be wrong but it might not have been cutting off the a/c at WOT.

I have 5v at the sensor and the signal voltage was within spec. Ill check to see if the computers getting the signal. The CEL isnt on and hasnt come on. It probably is shorted where it cuts out the compressor.
Thank You

 

[tompumped]

After rereading from what I understand it means that there is a short to power in the TP circuit which is the GY/W wire. I didn't realize it was telling me that it was that wire that was my issue in DH6. The picture below refers to that as the TP wire.

I used my loadpro for the first time and at wide open throttle I had five volts on that wire IIRC and when I applied the load it dropped to less than one volt.

It's crazy that I bought all these tools should the need ever arise again and I was like a deer in headlights. I have alldata, an EVTM, the FSM the wiring manual, the loadpro, the breakout box, large wiring diagrams the size of plans. It goes to show you can have the best tools that the dealerships use and it means nothing. I'm still not happy with myself but i've fixed every wiring issue i've ever came across without rigging or modifying the factory wiring.

Anyone can open up a harness and trace wires but to pinpoint which wire it is saves time and helps keep your head straight. Its just been years and i'm stressed bad over buying a SHO should've never bought let alone paid what I did.


For reference 46 is the GY/R, 47 GY/W, and 26 BR/W.

I found out today it only does it at WOT. If I let off just a little I can redline the car and it doesn't feel like I hit a wall at 6k.

 

[tompumped]

Well apparently I have no clue what i'm doing still. If someone can point me in a direction as to why there is an open between pins 47&57 i'd really appreciate it, or any direction at all. I can just swap harnesses but I want to learn.

I performed the test in step DH6 on the car I just bought and it had 3 Megaohms when I tested between pin 47 and 57. For reference between pins 47 & 26 I had 1.6 Kohm so the manual is incorrect where it states you should have over ten thousand ohms.

I jumpered from the tps to pin 47 and retested and I had nothing. So there isn't a short to power or high resistance in the gy/w wire.

 

[rubydist]

I have had random open circuits in the harness at various locations on these cars in the past, so if there is supposed to be connectivity but there is not, that is likely what you are experiencing. You can tear the harness all apart to find it, or you can do what I usually do and run a new wire and splice it in at the ends where you know its supposed to connect.

 

[tompumped]

I don't understand that when I jumpered the wire directly to the pcm connector there was still an open between pins 47 and 57. After looking at the wiring diagrams it appears that the two pins are connected internally through the pcm.

It would've made it much easier if I could've properly diagnosed it so I knew which wires I had to trace in the harness to make this work. Sadly I wouldn't know which wires to run new and i'd run all of them. I can't think clearly anymore. I might swap harnesses and tear it apart after. I need to take a break

I knew youd be the only one to respond thank you.

I just wanted to learn how to properly diagnose electrical issues again and regain some confidence.

 

[tompumped]

I remember one of my teachers at lincoln tech telling me youre going to come across cars you can't fix in your life and how you choose to handle it is up to you. He bought the car from the customer and set it on fire. That school had almost no hands on and the program was worthless twelve years ago. Maybe if it had been worth twenty grand i'd have learned something and I would've fixed this car.

I was going to take both harnesses off the rotted pos I just bought but I realized that there was a different plug that ties it into the interior harness. It was square instead of the two round ones. It took a different ccrm maybe that's how you identify the harness you need.

I tore apart the harness with the computer plug on it and there was nothing wrong with it at all anywhere. I did a continuity test and resistance on the three wires to the pcm plug and they were within the same range.

With those three wires jumpered directly to the pcm the issue is still there. I'm going to junk the car. This is the first time in my life I haven't fixed what I set out to.

 

[luigisho]

That is too bad but there is a cost:benefit analysis to be done with every job regarding monetary and time cost vs end result. If there are parts of the car worth saving pull them. I have a very short leash with electrical as the time I have available to invest, at my low skill level, makes me attempt for a bit and then evaluate if I want to pay a pro or walk away from the whole thing. Only ever paid a pro once to fix a clockspring (open up and solder) on a low mile car

 

[tompumped]

I might try running new wires and tapping into the wires at the computer connector before I junk it. Maybe one of the pins I used to backprobe the computer wasn't making good contact or it shifted when I test drove it with jumper wires. I'll probably see if anyone has a harness on here. If I fixed it i'd keep the car as a spare.

I put thousands into this car over the years. The engine in it has got me around for ten years and it's tired. I've never had to pay for a tow or had any major check engine issues. Every single bolt on the suspension has been replaced and every single component on it as well. I never sunk this type of money into a car to just maintain it and not go any faster. I still can't believe over the same time frame I had a sentra and I had to do barely anything to keep that car going.

I will take everything off the car and then some. I have more than enough free storage for all the parts I don't use, and it's nice to be able to store them out of sight so you don't feel like you're hoarding junk.

I realize I was all over the place and out of my mind trying to diagnose it at times or convey where I was at and what was happening. I used to be better and more patient.

Thankfully i've never paid once to have a car fixed in my life. If I was going to pay someone i'd drive it to the dealer and ask them if they would be willing to use my BOB and my 92 fsm with my gigantic wiring diagrams. If not the only other person i'd probably pay is that guy from south main auto, a coworker raves about his videos. I'm very apprehensive after seeing the shit i've seen working in the field for six years after school.

It's funny that you mention the clockspring. After I swapped a newer steering wheel in my '92 I had to solder a new connector on. At first I soldered the plug on the end in the wheel but the code was still there. I then went to a junk yard and got the plug that is by your knees that feeds a connector up to that plug from a separate harness and it eliminated my issue. The original plug up top I soldered on was a larger diameter wire and it must've changed the resistance in the circuit and the module sensed it but I truly don't know.

 

[rubydist]

If your engine is tired, it is almost certainly due to sticky piston rings, in my experience with these SHO motors. I have had very good experience with using Motorcraft semisynthetic oil in these engines - it does a very good job of freeing sticky rings and restoring compression. Once you get it running, I suggest you try a few oil changes with that.

 

[sperold]

Have a close look at the monster connector on the drivers inner fender and pull the harness tape back a few inched on both sides.
I found a wire that simply "exploded" due to it turning green and becoming about 2 X its usual diameter.
The other fault I found was where the monster connector turned down and resumed it travel, a wire had rubbed against the inner fender and it could not be seen until the connector was taken apart. this is the connector with the bolt in it.

With the help of your EVTM, you will be able to fix the issue. Buy a few spools of wire and get alligator clips on the end of long runs of your new wire and you will find the problems, but it does take a lot of time and sometimes it helps to involve another person.

You may have the green wire explosion issue, and the best I can figure is it gets its start when someone probes the wires with those sharp needle test lights, and wounds the wire cover if they are careless and aggressive.

 

[tompumped]

If your engine is tired, it is almost certainly due to sticky piston rings, in my experience with these SHO motors. I have had very good experience with using Motorcraft semisynthetic oil in these engines - it does a very good job of freeing sticky rings and restoring compression. Once you get it running, I suggest you try a few oil changes with that.

The spare motor I went through and put new heads on had stuck oil control rings on 4/6 pistons. I'll try that oil. The car is my only daily driver at the moment that's another reason i'm going crazy. It runs fine has full power and no CEL. Its like you hit a wall at a certain rpm and it will not advance. If you stay on it then the light will come one but it goes out within fifteen seconds of letting off. At first it was 6k now it's down to 5k for some reason.

Have a close look at the monster connector on the drivers inner fender and pull the harness tape back a few inched on both sides.
I found a wire that simply "exploded" due to it turning green and becoming about 2 X its usual diameter.
The other fault I found was where the monster connector turned down and resumed it travel, a wire had rubbed against the inner fender and it could not be seen until the connector was taken apart. this is the connector with the bolt in it.

With the help of your EVTM, you will be able to fix the issue. Buy a few spools of wire and get alligator clips on the end of long runs of your new wire and you will find the problems, but it does take a lot of time and sometimes it helps to involve another person.

You may have the green wire explosion issue, and the best I can figure is it gets its start when someone probes the wires with those sharp needle test lights, and wounds the wire cover if they are careless and aggressive.

I'll take a look right now for the **** of it. That's crazy i've never seen that happen.





Today I had the choice to leave work early and I rewired the tps using solder and adhesive lined heat shrink, but there was no change. I also tore apart the rest of the engine harness from the CCRM to where i'd checked prior and nothing. For the **** of it I checked the first splice after the +5v signal wire leaves the ccrm and there was no corrosion.

Whatever they used for adhesive lined heat shrink is amazing that shit is probably better than normal coating on wire. It was impossible to pull it off you had to shave it off with a razor blade. I'm thinking that I have an issue with the wire that feeds +12v to the ccrm from the underhood fuse panel. Any help would be much appreciated.

I also did the pinpoint test from the EVTM for the voltage reference wire and it passed the test.

The only code I have is a code 121

 

[tompumped]

I just found this. This bk/o wire coming from the underhood fuse panel was corroded bad. I don't understand how this could be the cause of my issues but since i've eliminated the tps/wiring/ecm I guess anything is possible. The 60a fuse for the wire says it only powers the fans but it gives power to four terminals in the ccrm.

The ecm power comes from a yellow wire to the ccrm. I believe that yellow wire provides the +5v signal wire. I'll have to check the diagrams again.

I also found out earlier today I have to push ******* a couple terminals on the breakout box to get it to make a connection. I probably had no issue with the tps wiring. It makes no sense to have the tool if you can't trust it and you have to double check in the end. Maybe there is slight corrosion on the pins from sitting in a damp basement for years, but they look clean as can be.

 

[tompumped]

That wasn't the issue.

 

[tompumped]

I gave way too much bad information and thought out loud to get help. Unfortunately the parts car I bought isn't road worthy and will never be, so i'm stuck with this pile of shit.

Even if I could have explained it properly I doubt you can truly get help for wiring issues without throwing money out there. The amount of time necessary looking through diagrams and connector face picture pinouts adds up. I never knew how valuable time can be until these past few years.

I'd love to pay someone to fix my car but I don't trust any shops at all let alone in this area.

It's gotten worse, it wont rev past five or fifty five. The only way to get the CEL to illuminate is to keep it floored when it wont rev anymore.

This car was a mess when I first bought it. It had a factory ford alarm system with key fob that was botched bad, I removed it. Plus the dash board was a christmas tree, and I had to swap my motor in plus my harnesses to make the lights go out.

 

[luigisho]

I agree with value of time and tackling electrical disasters

 

[tompumped]

I figured i'd look up what the procedure was for a code 121 on a 95 and it's unbelievable that gigantic 92 EVTM I bought is essentially useless for properly diagnosing certain codes.

Not only did the definition change from 92 to 95 but the procedures are drastically different depending on whether it's a KOEO hard code KOER hard code, KOEO memory code. Nowhere in my fsm did it mention anything about the MAF. When apparently I should've been looking there the whole time based on circumstance.

It's pretty unbelievable that the last step I end up at is G8 which is pictured below and it's testing the MAF.

 

[luigisho]

You can usually run a crude test and see if the car runs better with the MAF sensor unplugged vs plugged in. That's all I've done to diagnose them in the past. It won't run optimally but it will eliminate faulty readings causing the a:f ratio to get way out of whack

 

[Shoman594]

I had an issue very close to this. Under the throttle body you will see 2 plugs these are known ask the salt and pepper plugs. Round black and grey/white. If you move these around does it change the open? Mine had a bad connection inside the plug.

 

[tompumped]

You can usually run a crude test and see if the car runs better with the MAF sensor unplugged vs plugged in. That's all I've done to diagnose them in the past. It won't run optimally but it will eliminate faulty readings causing the a:f ratio to get way out of whack

I'll try unplugging it to see what happens. I have three sensors and one was known good that I used in the past. It's not a sensor issue.

I had an issue very close to this. Under the throttle body you will see 2 plugs these are known ask the salt and pepper plugs. Round black and grey/white. If you move these around does it change the open? Mine had a bad connection inside the plug.

I'll check those out. The strange thing is that when I do the resistance test the values are there sometimes, and then it just goes to open without anything happening.



Still hoping on getting another harness to at least rule that part out. I still can't believe how much of the diagnostic process changed and now it only makes sense as there can be three different modes of failure. I forgot the first codes listed are hard faults and then the memory faults.

 

[tompumped]

I can't find the video I took, but the intake tube was getting sucked closed. This was with an aftermarket fender snorkel and the factory tube.

I'd always used an aluminum elbow and it never fit quite right, but a turd I purchased back then had the stock tube routed in to the same type of setup and I thought it was a great idea to overcome the fact my bend was off by a few degrees.

The best part of the whole scenario was when another member led me on for a month saying they'd send me the harness I needed and never did.

This was after getting the wrong harness twice, but that other seller was great.