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Discussion Starter · #61 ·
I couldn't accept anything for what I do here because just like my day job, I sell Crack for the image, not the money.... But I digress.

If the male pin on the BJB and isn't showing battery voltage with the ignition on, and that wite has continuity between 18 BJB & 1 APP then you should be good on that side.

The next steps are you isolate the source of system voltage.

Start with the C1035C plugged in and PCM disconnected. Test PIN 12 on the PCM connector C1381B for voltage.

View attachment 413392
View attachment 413393

It will has the same color wire as the the APP sensor. It is shows battery voltage we needed to look at the engine harness somewhere.

Let me know what you find before we more forward
No voltage present. Continuity is also good
 

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No voltage present. Continuity is also good
Which means that you're not getting 12 VDC at PIN 18 at the BJB as well? Or shouldn't be.

I understand that this is a replacement PCM but I also warned you about plugging it in.

So if you have the everything plugged (except the PCM) and the ignition is on. PIN 18 doesn't have voltage on it, and neither does PIN 12. I'm going to say that something is probably shorting out the 5 VDC VREF on the PCM.

Plug in the PCM and test PIN 18 again. If the voltage above 5 VDC returns (battery voltage) something on the PCM or connected to it could be the problem.

Not too many things mingle both 5 & 12 voltage power. They have a tendency to interfere with each other. The 5 VDC VREF is considered "clean" because and 12 VDC "dirty".

Battery voltage is susceptible to noise generated by other things. Like Alternators, which output AC (alternating current) and a series of diodes convert it to DC (direct current) for use in the system.

If you have ever been in a car with a poor audio installation and you could hear the engine whine through the speakers, it was because of a poor ground and or failing diode in the alternator. You can hear the AC whine in the speakers.

Let's see if PCM causes the problem to return.

J
 

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Discussion Starter · #63 ·
Which means that you're not getting 12 VDC at PIN 18 at the BJB as well? Or shouldn't be.

I understand that this is a replacement PCM but I also warned you about plugging it in.

So if you have the everything plugged (except the PCM) and the ignition is on. PIN 18 doesn't have voltage on it, and neither does PIN 12. I'm going to say that something is probably shorting out the 5 VDC VREF on the PCM.

Plug in the PCM and test PIN 18 again. If the voltage above 5 VDC returns (battery voltage) something on the PCM or connected to it could be the problem.

Not too many things mingle both 5 & 12 voltage power. They have a tendency to interfere with each other. The 5 VDC VREF is considered "clean" because and 12 VDC "dirty".

Battery voltage is susceptible to noise generated by other things. Like Alternators, which output AC (alternating current) and a series of diodes convert it to DC (direct current) for use in the system.

If you have ever been in a car with a poor audio installation and you could hear the engine whine through the speakers, it was because of a poor ground and or failing diode in the alternator. You can hear the AC whine in the speakers.

Let's see if PCM causes the problem to return.

J
PCM plugged back in. I have above 5. Battery voltage
 

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PCM plugged back in. I have above 5. Battery voltage
Then something else is causing this. I need to look and see if anything shares the 5 VDC VREF BUS with the APP.
 

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I will be on standby! looking forward to your findings.
Everything plugged in & ignition on. Can you measure the exact voltage from C1035C.
Red lead PIN 18
Black lead PIN 28
And I mean the exact reading.
 

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I am getting between 12.92 and 12.97 doesn’t go stable. That’s with the jumper cables hooked up to my running truck. When I remove the jumper cables. The voltage steadily and quickly goes down til the batteries too dead to run accessories
I'd invest in a cheap trickle charger. At this point you don't want to kill 2 batteries in both your vehicle.

Everything keeps leaning towards your PCM but what caused the failure. I'm digging through the power distribution schema for the harness.

J
 
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Discussion Starter · #71 ·
I'd invest in a cheap trickle charger. At this point you don't want to kill 2 batteries in both your vehicle.

Everything keeps leaning towards your PCM but what caused the failure. I'm digging through the power distribution schema for the harness.

J
I live in an almost some apartments. The dorms on an air force base. I have to take the battery out and bring it inside to charge for the night so its inconvenient unfortunately.
 

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Discussion Starter · #72 ·
I'd invest in a cheap trickle charger. At this point you don't want to kill 2 batteries in both your vehicle.

Everything keeps leaning towards your PCM but what caused the failure. I'm digging through the power distribution schema for the harness.

J
Its also strange because my APPVREF2 reads a solid 5 volts. with no issues
 

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Its also strange because my APPVREF2 reads a solid 5 volts. with no issues
They have dedicated references (APPVREF1 vs others that share common VREF) its a safety thing because it's a throttle by wire as opposed to a cable operatored system.

(The 6.0 power stroke diesel throttles on fuel and doesn't even have a throttle. Some models had them but they weren't even functional. The setup had 3 pedal position sensors in the APP configuration.)

I ripped an entire harness apart last night just to verify that the APP runs directly from the PCM C1381B to the C1035C. It does without any additional splices. The fact that it only does so when the ignition is set to run/start and not constantly hot is also telling.

I haven't forgotten about you, it's hard enough most times to diagnose stuff like this in person let alone remotely from the bluegrass state! LoL!
 

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Discussion Starter · #74 ·
They have dedicated references (APPVREF1 vs others that share common VREF) its a safety thing because it's a throttle by wire as opposed to a cable operatored system.

(The 6.0 power stroke diesel throttles on fuel and doesn't even have a throttle. Some models had them but they weren't even functional. The setup had 3 pedal position sensors in the APP configuration.)

I ripped an entire harness apart last night just to verify that the APP runs directly from the PCM C1381B to the C1035C. It does without any additional splices. The fact that it only does so when the ignition is set to run/start and not constantly hot is also telling.

I haven't forgotten about you, it's hard enough most times to diagnose stuff like this in person let alone remotely from the bluegrass state! LoL!
no worries. Im tempted to put the car back together and take it to a mechanic but I've always done my own work and im scared of the pricetag that is to come with going thru a shop.

I can always PM you my phone number and shoot you over photos of anything you need if that helps at all.
 

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Been eyeballin' this thread as I do with most because I'm missing chromosomes that allow me to be as smart as most of the Dudes here. A few months back it was a heck of a rainstorm in Vegas and in the morning going to work of course things were complicated as in wrecks everywhere and it didn't matter what side streets I were on, so was 90% of the population. Anyhoo...I took 1 particular street to get to another (more direct side route) and before I knew it I was damn near knee deep in water and I wasn't trickling thru. Once I turned on the last street that would be a low point hazard for water and PARTED THE SEA LIKE MOSES that was all she wrote for rainwater. No issues just crud underneath (still need to clean that up a bit). Damn I either caught a God-like intervention/break or I don't know what to think. I feel for you and the troubles you are going thru. I hope it gets rectified correctly w/o a large pain to the wallet that says "Bad M'F'kr":cool:
 
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Discussion Starter · #76 ·
They have dedicated references (APPVREF1 vs others that share common VREF) its a safety thing because it's a throttle by wire as opposed to a cable operatored system.

(The 6.0 power stroke diesel throttles on fuel and doesn't even have a throttle. Some models had them but they weren't even functional. The setup had 3 pedal position sensors in the APP configuration.)

I ripped an entire harness apart last night just to verify that the APP runs directly from the PCM C1381B to the C1035C. It does without any additional splices. The fact that it only does so when the ignition is set to run/start and not constantly hot is also telling.

I haven't forgotten about you, it's hard enough most times to diagnose stuff like this in person let alone remotely from the bluegrass state! LoL!
A couple of people told me to try replacing the throttle body, do you think it is worth a shot?
It doesn’t make sense but I’m out of options before I pay the hefty mechanic price tag.
 

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A couple of people told me to try replacing the throttle body, do you think it is worth a shot?
It doesn’t make sense but I’m out of options before I pay the hefty mechanic price tag.
Absolutely. I thought you had before the pcm. In fact unplug the throttle body and perform the testing again. The throttle body has both 12 & 5 VDC present.
 

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Discussion Starter · #80 ·
They have dedicated references (APPVREF1 vs others that share common VREF) its a safety thing because it's a throttle by wire as opposed to a cable operatored system.

(The 6.0 power stroke diesel throttles on fuel and doesn't even have a throttle. Some models had them but they weren't even functional. The setup had 3 pedal position sensors in the APP configuration.)

I ripped an entire harness apart last night just to verify that the APP runs directly from the PCM C1381B to the C1035C. It does without any additional splices. The fact that it only does so when the ignition is set to run/start and not constantly hot is also telling.

I haven't forgotten about you, it's hard enough most times to diagnose stuff like this in person let alone remotely from the bluegrass state! LoL!
Just swapped in a new throttle body. Car idles fine then same thing. Limp mode right after I give it gas
 
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