EGR Valve

[warps]

Hi people,

So, diagnostics been quiet so brought it here. Car keeps shoping P1405.

Egr has been replace twice, dpfe upstream hose is clear and connected. Wires are 100% correctly connected to vehicle.

I have the 12v wire working. As do the ECU Controlled Ground. I have the 5v reference wire working. Then I have the signal wire and negative. When unplugged on all three egrs I get 0v on both of these wires. When connected I get 5v on both of these wires.

Any advice or further tests I can do?

[Rhubarb]

Yep you've probably blown the ecu messing about!

[chippie]

If you have a decent obd sscanner, you should be able to command the egr valve open and closed and read its position on live data...Tha will prove that the EGR valve and your ECU are talking..

If you connect, to a 12 v supply, to the solenoid, you should see the valve move back and forth...then if you supply 5v to the feedback section and measure between the GND and Signal wire, you should see the voltage change...between 0 and 5v...That will prove if your EGR valve is working electrically....Doesnt mean the valve and seat are doing their job..!!

[warps]

Sept 26, 2021 0:33:12 GMT 1 Rhubarb said:

Yep you've probably blown the ecu messing about!

Please don't assume I dived in without researching. The test on the original EGR showed the same results, I assumed it was the EGR valve.

After all the Negative and Signal are 0v when disconnected from the EGR, so there is no voltage coming from the ECU to the EGR on the Signal or Negative line. And yet when the EGR 8s connected the voltage seems to be passing over the resistive circuit. On all 3 EGR.

If the ECU is the cause its been like it a while, but how can the ECU be causing it?

[warps]

Sept 26, 2021 10:11:51 GMT 1 chippie said:

If you have a decent obd sscanner, you should be able to command the egr valve open and closed and read its position on live data...Tha will prove that the EGR valve and your ECU are talking..

If you connect, to a 12 v supply, to the solenoid, you should see the valve move back and forth...then if you supply 5v to the feedback section and measure between the GND and Signal wire, you should see the voltage change...between 0 and 5v...That will prove if your EGR valve is working electrically....Doesnt mean the valve and seat are doing their job..!!

I've manually grounded the EGR with the engine running and the engine was stalling. Surely that is evidence the valve works? So I need to manually activate the valve and see what the signal wire comes up with?

[Rhubarb]

Sept 26, 2021 10:25:54 GMT 1 warps said:

Sept 26, 2021 0:33:12 GMT 1 Rhubarb said:

Yep you've probably blown the ecu messing about!

Please don't assume I dived in without researching. The test on the original EGR showed the same results, I assumed it was the EGR valve.

After all the Negative and Signal are 0v when disconnected from the EGR, so there is no voltage coming from the ECU to the EGR on the Signal or Negative line. And yet when the EGR 8s connected the voltage seems to be passing over the resistive circuit. On all 3 EGR.

If the ECU is the cause its been like it a while, but how can the ECU be causing it?

You don't appreciate how delicate and sensitive electronic components are inside an ECU..

Ground a wire out and blow a capacitor for instance.

[Rhubarb]

Sept 26, 2021 10:28:44 GMT 1 warps said:

Sept 26, 2021 10:11:51 GMT 1 chippie said:

If you have a decent obd sscanner, you should be able to command the egr valve open and closed and read its position on live data...Tha will prove that the EGR valve and your ECU are talking..

If you connect, to a 12 v supply, to the solenoid, you should see the valve move back and forth...then if you supply 5v to the feedback section and measure between the GND and Signal wire, you should see the voltage change...between 0 and 5v...That will prove if your EGR valve is working electrically....Doesnt mean the valve and seat are doing their job..!!

I've manually grounded the EGR with the engine running and the engine was stalling. Surely that is evidence the valve works? So I need to manually activate the valve and see what the signal wire comes up with?

You really have no understanding of how an egr works and is controlled do you?!

[chippie]

Like I said in my post earlier,
Drive the egr from a scantool.....this will prove egr/wiring and ecu are working...if you cannot do this, then you need to get help from someone who can, otherwise you are wasting your time.

[warps]

Sept 26, 2021 12:28:25 GMT 1 Rhubarb said:

Sept 26, 2021 10:25:54 GMT 1 warps said:

Please don't assume I dived in without researching. The test on the original EGR showed the same results, I assumed it was the EGR valve.

After all the Negative and Signal are 0v when disconnected from the EGR, so there is no voltage coming from the ECU to the EGR on the Signal or Negative line. And yet when the EGR 8s connected the voltage seems to be passing over the resistive circuit. On all 3 EGR.

If the ECU is the cause its been like it a while, but how can the ECU be causing it?

You don't appreciate how delicate and sensitive electronic components are inside an ECU..

Ground a wire out and blow a capacitor for instance.

I understand that and appreciate it perfectly. I havnt done anything without consulting wiring diagrams and online videos. Of multiple types before going near the electrics.

Auto electrics are a pain in the ass for the professionals, let alone a rookie lol

[warps]

Sept 26, 2021 12:34:48 GMT 1 chippie said:

Like I said in my post earlier,
Drive the egr from a scantool.....this will prove egr/wiring and ecu are working...if you cannot do this, then you need to get help from someone who can, otherwise you are wasting your time.

I'll see if any of my mates have a tool that can handle it. Mine is a basic OBD Reader.

[rhyds]

Sept 26, 2021 12:28:25 GMT 1 Rhubarb said:

Sept 26, 2021 10:25:54 GMT 1 warps said:

Please don't assume I dived in without researching. The test on the original EGR showed the same results, I assumed it was the EGR valve.

After all the Negative and Signal are 0v when disconnected from the EGR, so there is no voltage coming from the ECU to the EGR on the Signal or Negative line. And yet when the EGR 8s connected the voltage seems to be passing over the resistive circuit. On all 3 EGR.

If the ECU is the cause its been like it a while, but how can the ECU be causing it?

You don't appreciate how delicate and sensitive electronic components are inside an ECU..

Ground a wire out and blow a capacitor for instance.

Or even blow the transistor based driver section of the ECU, which is distinctly sub-optimal to operations.

[warps]

So,

A friends plugged his scanner in but the car didn't want to show EGR voltage or percentage. Apparently not all cars support that but I don't know that bit.

So, we grounded the egr and monitored the voltage separately.

The valve is moving physically, but the signal voltage doesn't move from about 5v. All three wires stay at approximately 5v regardless of the position of the pinion.

[rhyds]

Sept 26, 2021 12:34:48 GMT 1 chippie said:

Like I said in my post earlier,
Drive the egr from a scantool.....this will prove egr/wiring and ecu are working...if you cannot do this, then you need to get help from someone who can, otherwise you are wasting your time.

@wraps

chippie is on the money here. Getting the ECU to drive the valve for you to test is the only real way of checking the EGR valve and wiring as a whole, and confirming the ECU hasn't been blown to bits when you caused a dead short on your 12v rail and blew that oxygen sensor supply fuse.

If you haven't done so, buy or borrow a decent scantool to check the EGR valve, and if it doesn't work source a known good OE EGR valve, either brand new or a 100% confirmed working (with scantool) s/h unit.

[rhyds]

Sept 26, 2021 16:35:39 GMT 1 warps said:

So,

A friends plugged his scanner in but the car didn't want to show EGR voltage or percentage. Apparently not all cars support that but I don't know that bit.

So, we grounded the egr and monitored the voltage separately.

The valve is moving physically, but the signal voltage doesn't move from about 5v. All three wires stay at approximately 5v regardless of the position of the pinion.

Is this EGR valve a known good unit? Or a second hand one?

[warps]

Sept 26, 2021 16:38:52 GMT 1 rhyds said:

Sept 26, 2021 16:35:39 GMT 1 warps said:

So,

A friends plugged his scanner in but the car didn't want to show EGR voltage or percentage. Apparently not all cars support that but I don't know that bit.

So, we grounded the egr and monitored the voltage separately.

The valve is moving physically, but the signal voltage doesn't move from about 5v. All three wires stay at approximately 5v regardless of the position of the pinion.

Is this EGR valve a known good unit? Or a second hand one?

Second hand... all three are second hand so maybe I'm just having bad luck. I'll have a look online for a new one. Something that will be guaranteed to work.