ECM, electrical issues...gremlins?

[Valkyrie14]

So this is a follow up thread on “Battery Issues”. I replaced the battery and the alternator is fine.

The issues are passenger turn signal that sometimes works and sometimes doesn’t. Ambient interior lights that turn off and an without any clear causal reason. A/C disabled due to high heat signal comes on, even though the car just started and it is cold outside. The cause of that signal is the oil temp sensor and coolant temp sensor not working. But then they come back on. And voltage is runs between 14-15V. Which is within operating range, but not normal.

I am now looking at the ECM or wire issue. Anyone know how to check the ECM? I really don’t want to run through the whole wire system if I don’t have to.

[Valkyrie14]

Forgot to mention. Unplugging the ECM wire harnesses for 30 seconds temporarily fixes some of the issues.

[Tarendor]

Check your codes and see if you have one that says the the ecu or bcm lost temp connection. How are your grounds?

[AlanRubin]

All my issues were bad connections (pins into the header) at the X2 ECU connector.
I pulled the X2 and X1 plugs out, and carefully, SLIGHTLY, bent the pins away from
each other at the X2 connector. When you pull the header off, it looks like two SCSI
Hard Drive ports, ha ha. Well, I just spread the pins apart, and everything has been
fine since. IT got so bad that Injectors were losing their connections. The holes in
the plug are no loner TIGHT after a while. So, it was either re-pin the connector,
or spread the pins apart at the ECU to make friction contact in the header.

This happens over time because the wires from being clipped into the engine,
to the ECU plugs. The motor, as it torques from braking and accelerating,
puts some stress on the plugs as it pulls on the wires from side to side. Mine also
got so bad, that if I were to apply a very little amount of twist on the X2 plug, the
motor would run so bad I would have to turn it off. So, I knew a bunch of pins were
losing contact in the header. I was getting a continual P062B code, when I would
brake too hard, or under hard acceleration. Well, no longer after cleaning the pins,
and spreading them apart.

Originally Posted by Tarendor

Check your codes and see if you have one that says the the ecu or bcm lost temp connection. How are your grounds?

Those U codes are for CAN BUS communications losses between MODULES, not
sensors. You will get P codes for sensor grounds, voltage or signal losses.

[redcoats1976]

thats good to know .i hate electrical gremlins.its much easier to do brake jobs or replace a radiator than mess with electrons.

[Valkyrie14]

Only codes I have currently are permanent from the FPCM related to the dual fuel pump. All is well there. No new codes.

To be honest I was irritated by the ambient lights and other issues. But the lack of a turn signal will get me pulled over. I would just get a new ECM if I knew that would solve it.

But to answer the question no ECM or BCM codes.

[Valkyrie14]

Originally Posted by AlanRubin

All my issues were bad connections (pins into the header) at the X2 ECU connector.
I pulled the X2 and X1 plugs out, and carefully, SLIGHTLY, bent the pins away from
each other at the X2 connector. When you pull the header off, it looks like two SCSI
Hard Drive ports, ha ha. Well, I just spread the pins apart, and everything has been
fine since. IT got so bad that Injectors were losing their connections. The holes in
the plug are no loner TIGHT after a while. So, it was either re-pin the connector,
or spread the pins apart at the ECU to make friction contact in the header.

This happens over time because the wires from being clipped into the engine,
to the ECU plugs. The motor, as it torques from braking and accelerating,
puts some stress on the plugs as it pulls on the wires from side to side. Mine also
got so bad, that if I were to apply a very little amount of twist on the X2 plug, the
motor would run so bad I would have to turn it off. So, I knew a bunch of pins were
losing contact in the header. I was getting a continual P062B code, when I would
brake too hard, or under hard acceleration. Well, no longer after cleaning the pins,
and spreading them apart.


Those U codes are for CAN BUS communications losses between MODULES, not
sensors. You will get P codes for sensor grounds, voltage or signal losses.

So inside the harnesses that connect to the ECM you went in and pried each pin wide?

[AlanRubin]

Originally Posted by Valkyrie14

So inside the harnesses that connect to the ECM you went in and pried each pin wide?

Yep. It's an old trick. PCs with Floppy drive, IDE, and SCSI headers on
the motherboard. When the plug holes would wear. In order to keep the
floppy, or HDD working after plugging and unplugging it so many times? We
just spread the pins apart, and it was fixed. I applied the same fix to the the
ECU pins, and the car has been running ever since.

I used a plastic pry tool, inserted it between the pins, and spread them
apart. EVERYTHING has gotten better. I used to have slow cranking, and
ever since this was done, cranking has been much faster now, all the
time. I suppose it had something to do with the current sensor inputs
to the ECU, or whatever other signals regulate battery charge. I have
a volt meter in the dash that is always on so I can see where the battery
is. IT was 12.4, to 12.6 before I did this, and now it's been as high as
12.8 before starting. The ECU does regulate battery charge based off
the current sensor, and defaults when it does not see the signal. So,
whatever that issue was, it has been so much better.

I just remembered how I used to fix PC devices when the plugs got
bad, and I just figured, WTF, I know it will work, just don't know for
how long. It's been a month or so since. I mean, you could just go
buy a new FDD or HDD cable, but when one was not available, you
did what you had to do. Plus, you aren't just fixing an ECU header by
simply replacing it.

[Valkyrie14]

Originally Posted by AlanRubin

Yep. It's an old trick. PCs with Floppy drive, IDE, and SCSI headers on
the motherboard. When the plug holes would wear. In order to keep the
floppy, or HDD working after plugging and unplugging it so many times? We
just spread the pins apart, and it was fixed. I applied the same fix to the the
ECU pins, and the car has been running ever since.

I used a plastic pry tool, inserted it between the pins, and spread them
apart. EVERYTHING has gotten better. I used to have slow cranking, and
ever since this was done, cranking has been much faster now, all the
time. I suppose it had something to do with the current sensor inputs
to the ECU, or whatever other signals regulate battery charge. I have
a volt meter in the dash that is always on so I can see where the battery
is. IT was 12.4, to 12.6 before I did this, and now it's been as high as
12.8 before starting. The ECU does regulate battery charge based off
the current sensor, and defaults when it does not see the signal. So,
whatever that issue was, it has been so much better.

I just remembered how I used to fix PC devices when the plugs got
bad, and I just figured, WTF, I know it will work, just don't know for
how long. It's been a month or so since. I mean, you could just go
buy a new FDD or HDD cable, but when one was not available, you
did what you had to do. Plus, you aren't just fixing an ECU header by
simply replacing it.

So I looked at all three fuse boxes, no apparent issues. Discovered I had a Mild to Wild unit on the trunk fuse panel. Removed and will sell if anyone is interested, no remote.

I pulled the ECM harnesses and gently spread the pins. I also applied some dielectric grease.

I then pulled the rear taillight to see if anything was apparent, and of course it all looks normal.

Put it all back together and at first the pass. Rear tail light still didn’t work. Then I fired it up and the light worked. I will check again to see if it goes off again.

Battery with car off after sitting all night was at 15.8V. I could have a cheap multimeter, but it is still probably high voltage.

Glad that light is working for now, but no understanding of what is happening. No related CEL or any other indicators.

[joekono]

Originally Posted by AlanRubin

Yep. It's an old trick. PCs with Floppy drive, IDE, and SCSI headers on
the motherboard. When the plug holes would wear. In order to keep the
floppy, or HDD working after plugging and unplugging it so many times? We
just spread the pins apart, and it was fixed. I applied the same fix to the the
ECU pins, and the car has been running ever since.

I used a plastic pry tool, inserted it between the pins, and spread them
apart. EVERYTHING has gotten better. I used to have slow cranking, and
ever since this was done, cranking has been much faster now, all the
time. I suppose it had something to do with the current sensor inputs
to the ECU, or whatever other signals regulate battery charge. I have
a volt meter in the dash that is always on so I can see where the battery
is. IT was 12.4, to 12.6 before I did this, and now it's been as high as
12.8 before starting. The ECU does regulate battery charge based off
the current sensor, and defaults when it does not see the signal. So,
whatever that issue was, it has been so much better.

I just remembered how I used to fix PC devices when the plugs got
bad, and I just figured, WTF, I know it will work, just don't know for
how long. It's been a month or so since. I mean, you could just go
buy a new FDD or HDD cable, but when one was not available, you
did what you had to do. Plus, you aren't just fixing an ECU header by
simply replacing it.

Yup, this is a great trick Alan. Been in the business over 30 years and boy if you have a pin issue like you described, it will drive you crazy. I'm surprised though that automobiles wouldn't have tougher connectors unlike the tiny one on a computer,printer etc. You also have to be careful and not break the pin or you are screwed!

[Valkyrie14]

Originally Posted by joekono

Yup, this is a great trick Alan. Been in the business over 30 years and boy if you have a pin issue like you described, it will drive you crazy. I'm surprised though that automobiles wouldn't have tougher connectors unlike the tiny one on a computer,printer etc. You also have to be careful and not break the pin or you are screwed!

I used a pick tool in between the rows and twisted the tool very gently just pressing the pins out a micro-meter. Totally freaked out by the idea of breaking a pin.

[Valkyrie14]

Still not fixed, turn signal off again.

Did discover that the plug wire boot protector was burnt through and the wire is melted the 4th cylinder.

Can a plug wire affect the ECM like that?

[AlanRubin]

The ECM does not control the lighting, that's the body control module.

I mean, that can cause a misfire on#4, but won't effect the lighting of the car.

[Valkyrie14]

Originally Posted by AlanRubin

The ECM does not control the lighting, that's the body control module.

I mean, that can cause a misfire on#4, but won't effect the lighting of the car.

Well crap. So BCM would be affecting turn signal?