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4 wire egr valve

posted Jul 01, 2016 08:18:20 by TimBingley
I need an explanation on how a 4 wire egr valve works. I have a power and a ground and a egr control and egr position. How does the computer know what the actual position is ? Why does it need a power and a ground ?
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16 replies
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Tyler said Jul 01, 2016 12:56:47
Hey Tim! Could you give us an example of a vehicle with this kind of valve? Helps as far as finding a relevant wiring diagram.
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TimBingley said Jul 01, 2016 18:01:22
Sure. 2014 International Lonestar with the Maxxforce 13 motor.
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Chris said Jul 01, 2016 23:37:46
Haven't worked on a max force but based on what you've said your wire designations are. Power and ground, your position wire is just a voltage feed back to the ecm and the EGR control wire is probably a PWM controlled that opens or closes the valve based on the applied duty cycle.
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Chris said Jul 01, 2016 23:38:13
Do you have a photo of the valve?
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TimBingley said Jul 01, 2016 23:55:38
So the egr control and the egr position is maybe the power and ground for the opening and closing of the valve ? The power and ground still confuses me.
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TimBingley said Jul 01, 2016 23:59:16
This is a double flap egr. One side does 1 2 and 3 and the other side does 4 5 and 6.
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Chris said Jul 02, 2016 00:42:34
1 dedicated power wire, 1 dedicated ground wire, 1 position sensing wire, and 1 control wire.
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TimBingley said Jul 02, 2016 02:45:53
I would love to see a schematic showing what is going on inside this thing. There must be a circuit board inthere then maybe ?
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PaulDanner said Jul 02, 2016 04:56:58
Probably a modified thermistor type circuit like they use on GM fuel tank level sensor circuits. That would be two of your wires and the other two wires would be a standard control.
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Tyler said Jul 02, 2016 14:53:07
I was also thinking along the same lines as Paul and Chris. One of the stranger setups I imagined involved switched power for the solenoid, steady ground (shared between the solenoid and position sensor), 5V ref and valve position signal.

Probably NOT the way it's set up, but I kinda had fun theorizing. Unfortunately I have no access to International diagrams...
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TimBingley said Jul 02, 2016 18:12:36
Thermistor on a fuel level circuit ? I must have missed something here. Or did you mean potentiometer ?
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TimBingley said Jul 02, 2016 18:28:30
I have a diagram here. I hope you can read.
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Tyler said Jul 02, 2016 21:20:22
Hey, nice! The wire designations are a bit blurry, but it definitely helps.

I see steady power and ground, the one wire going to the ECU, and one going to the on/off engine harness interface. The one wire going to the ECM is obviously control, but what about the wire going to this interface? Just wondering out loud.

Any chance of getting some voltage measurements at this valve, plugged in and unplugged?

Also, check out this video if you're wondering about the fuel level sensor thing Paul mentioned:

https://youtu.be/SIR-quUzZwY

Think of it as a potentiometer with two wires instead of three.
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TimBingley said Jul 07, 2016 03:03:53
So to get at the valve is not possible. I was able to back probe at a different connector for all but one. I have battery voltage and a good ground for 2 of them. EGRP has 5 volts. It's not pulsed at all. I was able to unplug the valve and I still had 5 volts on that wire. Now I'm starting to think wiring problem. I would love for someone to explain the circuitry inside this valve. Paul we need a video on 4 wire pwm egr valves.
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TimBingley said Jul 09, 2016 01:18:37
I got some info. I decided to check the electronic throttle valve and share my readings. This valve and the egr valve are similar. They are both four wire.
The etv readings are:
Plugged in:
Power 14 volts
Ground 0 volts
Position pulsed 1 volt to 6 volt
Control pulsed 0 volt to 9 volt

Unplugged:
Power 14 volts
Ground 0 volts
Position 13 volts
Control 0 volts - after plugging back in it was a steady 8.3 volts.

My egr valve I was able to probe unplugged only. Everything is similar except position is only 5 volts instead of 13 volts.
[Last edited Jul 09, 2016 01:49:17]
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