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Falsely overheated

pcb

The Diagram Dude
:
2002 MP5
This is my CDCV valve from my parts car.
The rotten piece of crap. Lol





But it's got sealed wires and a seal in the connector and it still looks new inside.








 
hello! i’m back lol
I replaced that bad wire and still no luck. i’m not 100% sure it was even the right wire and i’m getting extremely discouraged because I don’t understand the diagrams in the book I have.

the wire I fixed was a group of 5 small orange wires leading to one so I took out the chunk that was cut multiple times and replaced it with a fresh one.

I guess my question is what do I do next if that didn’t resolve the issue? should i trace back from where the sensor is at and check those wires?
 

Attachments

pcb

The Diagram Dude
:
2002 MP5
Don't give up yet.

What did you do with those 5 wires?

Did you reconnect them to the white wire that you installed?

Where do those 5 orange wires go?
Are they spliced back in under the hood?

Check for any splices and make sure they have good contact.

Somebody already fixed your problem and the fix has failed.
(your car was working.)


I really think you're on the right track.

You need continuity from the ECU to all the orange wires.
 
I reconnected the 5 orange wires to the white wire, well first I taped them together so they’d stay all intact instead of being loose. then i attached them to the white wire.

so I need to start from the sensor and just follow them from under the hood?

i also connected the new sensor clip to the original wires (orange and purple) those seem to be fine but i’m assuming I just need to keep digging and checking?

I got frustrated after I took out my battery, the plate it sits on, the air filter and hoses so I could see all the ways the wires go.

it’s definitely a mission lol
 

pcb

The Diagram Dude
:
2002 MP5
I'm thinking that when the problem originally started, a probe was stuck into the ECU connector on the orange wire.
A bit like this... (this is my fuse box connector though )








This is before I plugged the probe into my wire connector tab.







This is after I jammed my probe in there.






I'll bet it no longer makes contact with the pin.



There are a whole bunch of wires coming out of your ECU connector that aren't being used.

You could remove one and replace the orange wire/tab/connector.


In the meantime, try to see if you have continuity from your orange wire at your temp sensor to the orange wire at your ECU connector.


Do you have a standard transmission or automatic or an automatic with "Tiptronic" ?
 
should I just stick the white wire into an open spot on the ECU and if no how to get it into the spot? i’m assuming it’s not as simple as just sticking it in and that’s it.

it’s an automatic
 

pcb

The Diagram Dude
:
2002 MP5
should I just stick the white wire into an open spot on the ECU and if no how to get it into the spot? i’m assuming it’s not as simple as just sticking it in and that’s it.
That won't make good contact and it will fall out.


A proper clip will lock in.
 

pcb

The Diagram Dude
:
2002 MP5
The white wire (which was originally orange) needs to connect to pin number 91 on the ECU.

That metal tab can be removed from the connector and replaced with an unused wire/tab/connector from elsewhere in the connector.





Pins number 81, 82, and 84 are apparently unused by the ECU and can be removed from the connector then plugged into pin # 91 then connected to your white wire.









You reach into the connector with a pin or needle to push the little tab to release it from the plastic connector.
You reach in from the wire side of the connector.

You'll probably need a pair of strong reading glasses.


All of that is assuming that you have continuity along the full length of the orange wire from the sensors to the ECU and it isn't making contact from the metal tab to the pin on the ECU.

This is a wire removed from a connector.
Your connector/tab may have a slightly different shape or size because it is from a different connector.


 

pcb

The Diagram Dude
:
2002 MP5
EDIT: pins #81,82 and 84 are used if you have an automatic transmission.

They are not used for my standard transmission.





However, you have ABS so your input/turbine speed sensor is not being used.

The ECU gets speed info from the ABS head unit if the car has ABS.

So the wires from pin #84 or #23 could be removed and used on pin #91.

Start with finding out if you have continuity along the full length of the orange wire, from the ECU to the sensor.

That orange wire also goes to both O2 sensors, the throttle position sensor, and the transaxle fluid temperature sensor.

Check that orange wire under your splice and see if you have continuity between it and the metal case of the ECU or body ground.

The wire may be shorted to ground.

It is a ground wire but it is supposed to be isolated from body ground and the signal may be lost if it touches body ground.


Look in the little hole on pin #91(the orange wire) to see if there is any obvious signs of damage to the metal tab by comparing it to the others around it.
 
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pcb

The Diagram Dude
:
2002 MP5
You can also connect another white wire to the five-wire splice and string it all the way to the orange wire on your temperature sensor and splice it in there.

That would be relatively easy to do.

Just restring the entire wire.
 
I got it out!
I tried to put it into an open slot and still nothing. I tried to go to the slots you had suggested but they all had wires in them.

Should i remove the orange wire from the connector and put the white wire in?
 

Attachments

also how important is it that the wire is the same size? I couldn’t find small enough, i’m thinking the orange wire is 24guage and i got 18.

i’m going to order some just because i wanna try every possibly
 

pcb

The Diagram Dude
:
2002 MP5
That orange wire needs to connect to pin #91.

It appears to be in good shape so it may be making proper contact with the pin on the ECU.

Being as you've got it out, connect an ohmmeter to the metal clip and with a big long wire connected to the ohm meter, probe the other probe of the ohmmeter to the orange wire of your temp sensor wire or its connector to check for continuity.

That orange wire is probably broken or disconnected somewhere along its length.

The signal isn't making it from the sensor to the ECU.
 
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pcb

The Diagram Dude
:
2002 MP5
I'm pretty sure my ECU only has a single orange wire coming out on pin #91.

The orange wire goes through a bunch of connectors where it splits off 4-5 ways to supply a ground for those sensors.

It appears that whoever fixed your car fed each orange wire all the way from the engine bay to the ECU.
 
Just browsed the schematic; that orange wire is the ground return for all sensors, that we agree on. If that wire was not making to the ECU plug then a whole load of other sensors wouldn't work and the car would -maybe- not even run at all.

What the OP needs to do is verify that the Violet/Yellow wire is making it to the ECU [pin 38]. Easiest way is to measure [with the ohmmeter setting] between pins 38 and 91 of the ECM connector. It should read SOME resistance, -the sensor's resistance. If open circuit THEN follow wires.

Above should be done with all connectors plugged in, battery disconnected.
 
i’m unable to get ahold of an ohmmeter so i’m not sure what to do exactly.

I can try and follow the wires from the sensor to the ecu and see if any spots are bad.
 
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