Focus egr problem.

Ask for and share advice on using the PicoScope kit to fix vehicles here.

Focus egr problem.

Postby djmikeyboy » Tue Nov 06, 2012 9:05 pm

Hi,
I'm trying to fix a recurring p0409 egr circuit high fault on an 04 Focus 1.8 TDCI. I have checked all the wiring between the ECU and EGR valve for continuity and I have removed and cleaned the inlet manifold mechanical part of the valve. Does anyone have a scope pattern for the readings at the valve motor itself please?

I have been checking data against autodata and I am not getting the correct position signals. With the motor section removed and resting on the engine if I manually turn the motor slightly the output position signal rises ok indicating that the potentiometer section is working ok.(on the assumption that the valve should move slightly on tickover? If anyone can confirm that it stays resting on it's stop at tickover then I will know that it's at fault as it is not outputting the 0.6 volts that autodata says it should be)

When the engine is switched off the motor flies full cycle up and back several times indicating that it is capable of working, I just need to know what voltage/scope pattern I should expect at idle. I'm thinking that either the motor is weak and is not moving enough with a low pulse, or the ECU simply isn't sending it a strong enough pulse to open it slightly.

I did obtain a second hand motor which is exactly the same although of course I can't rule out it being any good either despite the breaker saying it was ok.

Any help would be greatly appreciated, I bought my picoscope because of this job and so am a bit new to it, but am determined not to be beaten by it. Again any input would be most appreciated thanks.


----------------------------------------
Edit by Admin : Added paragraphs
djmikeyboy
User
User
 
Posts: 10
Joined: Tue Nov 06, 2012 8:47 pm

Re: Focus egr problem.

Postby Robski » Wed Nov 07, 2012 7:21 am

Happy with just continuity testing ?

A few paragraphs would have been a treat on the eyes too.

Is it receiving a command to move off the stop ?

5V ref/ground checked ?
User avatar
Robski
Advanced User
Advanced User
 
Posts: 602
Joined: Tue Sep 14, 2010 6:36 pm
Location: Yorkshire

Re: Focus egr problem.

Postby djmikeyboy » Thu Nov 08, 2012 12:05 am

Hi, sorry about not using paragraphs, new to using forums. How should I be testing the wiring properly? I know I need to measuring current draw etc but I'm new with my scope and don't know how to yet.

I have constant 5v ref and 0v earth (pico scoped am I correct in thinking that if the earth was poor I would get a voltage reading or am I getting that wrong?)

It is getting a fluctuating voltage command but not much of one, hardly 1 volt. This is the info I am struggling to clarify, I need to find out what scope pattern I should expect to see.

Any advice on how to connect the pico scope to properly test the loom would be appreciated, would it be to connect a volt meter pos and neg either end and if I get a reading then there is a resistance in the wire?

Thanks for responding so quickly
Mike
djmikeyboy
User
User
 
Posts: 10
Joined: Tue Nov 06, 2012 8:47 pm

Re: Focus egr problem.

Postby Liteace » Thu Nov 08, 2012 12:40 am

As per per usual I'm a little confused, you say it an 04 1.8 tdci are these not fitted with a vacuum controlled EGR and solenoid valve, I thought they didnt fit the motor controlled EGR till about 06, there's not a cut and shut in the loom anywhere is there, maybe inlet man or engine replaced with one from a later vehicle !
DONT SHOOT YOURSELF IN THE FOOT
Liteace
Guru
Guru
 
Posts: 145
Joined: Fri Jan 27, 2012 12:25 pm

Re: Focus egr problem.

Postby Robski » Thu Nov 08, 2012 7:59 am

A quick look on AD said it had a position sensor hence my reply.

OP are you in the trade ? I shouldn't really need to tell you how to load test. One way would be a channel deployed each end of the circuit in question with a maths channel (current flowing).

Post the captures you have taken so we can see what's going off ??
User avatar
Robski
Advanced User
Advanced User
 
Posts: 602
Joined: Tue Sep 14, 2010 6:36 pm
Location: Yorkshire

Re: Focus egr problem.

Postby Liteace » Thu Nov 08, 2012 8:06 am

Robski wrote:A quick look on AD said it had a position sensor hence my reply.

OP are you in the trade ? I shouldn't really need to tell you how to load test. One way would be a channel deployed each end of the circuit in question with a maths channel (current flowing).

Post the captures you have taken so we can see what's going off ??


Yep even the vacuum controlled EGR does have position sensor, to change it or the EGR you have to change the complete intake manifold, Fords must of been having a french day when they thought that one out. I think 04 was the change over year so it could have the motor controlled jobby

:D
DONT SHOOT YOURSELF IN THE FOOT
Liteace
Guru
Guru
 
Posts: 145
Joined: Fri Jan 27, 2012 12:25 pm

Re: Focus egr problem.

Postby Robski » Thu Nov 08, 2012 8:16 am

I meant to say motor as well :oops:
User avatar
Robski
Advanced User
Advanced User
 
Posts: 602
Joined: Tue Sep 14, 2010 6:36 pm
Location: Yorkshire

Re: Focus egr problem.

Postby djmikeyboy » Fri Nov 09, 2012 6:44 pm

Sorry everyone, my bad ,it is an 06 Focus, I don't know why I put 04. It definately has a 5 pin motor, three for the position sensor and two for the motor. Yes I am in the trade and have been for over 20 years, unfortunately I have spent them all working for independant bosses who didn't like spending money on updating training. I've had to learn everything as I've gone along which is why I'm not as up to speed as I'd like to be with modern electronics. Now I am branching out into self employment I am playing catch up.
I will endevour to post some captures of what is happening tomorrow, sorry for causing confusion, and thanks again for your willingness to assist.
Mike
djmikeyboy
User
User
 
Posts: 10
Joined: Tue Nov 06, 2012 8:47 pm

Re: Focus egr problem.

Postby djmikeyboy » Sat Nov 10, 2012 1:08 pm

Hi again, my last post hasn't been approved yet but I was incorrect with the model year, it is in fact a 2006 Focus. Apologies again for the confusion I have caused. I have taken wave forms from each of the wires from the ECU to the EGR at both ends with a math channel to prove that the loom appears to be ok.

In all captures Channel A (Blue) is connected at the EGR end, channel B (red) is at the ECU end and the math channel is purple.

Bc3 ide.psdata
Pin Bc3 from Ecu 5v reference ign on. Ok as far as I can see. Is the same at Idle.
(1.17 MiB) Downloaded 240 times

Bd2 ignon.psdata
Pin Bd2 from ECU this should be 0.6v ign on,which it is not. However with motor section detached and manually turned the voltage wil rise proving that the potentiometer is working.
(344.53 KiB) Downloaded 194 times

Bd2ide.psdata
Pin Bd2 again at idle this time. Shoud be 2.6v again it is not due to motor not moving.
(351.58 KiB) Downloaded 183 times

Be2 ide.psdata
Pin Be2 ground for potentiometer. Ok as far as I can see. Tested at ide.
(255.28 KiB) Downloaded 189 times

Bl2 ignon.psdata
Pin Bl2 from ECU, should be 0-1v but there are a few flicks above 1v? Is this ok or not? Tested with ign on.
(239.51 KiB) Downloaded 189 times

Bl2ide.psdata
Pin Bl2 again at idle this time, same few flicks above 1v?
(225.25 KiB) Downloaded 189 times

Bm2 ignon.psdata
Pin Bm2 from ECU this should be 1200Hz ign on. I hold my hands up on this one as I don't know how to set the scope up to measure Hz? The wave pattern is competely different to the one shown on Autodata though.
(220.57 KiB) Downloaded 192 times

Bm2 ide.psdata
Pin Bm2 again at idle this time. Confused again, Autodata says it should be 14%? I do not know what I am looking at for this? But wave pattern again is totally different to the picture shown
(230.13 KiB) Downloaded 191 times


The EGR motor does not move off it's stop at all at idle, although it will cycle fully when the engine has been running for a few minutes and is switched off.

Hopefully I have done this right and you can see my captures. My thinking is that the ECU is not sending the correct command to the EGR motor. If so are there any other signals I should be checking to the ECU before I condemn it?


Many thanks in advance

Mike
djmikeyboy
User
User
 
Posts: 10
Joined: Tue Nov 06, 2012 8:47 pm

Re: Focus egr problem.

Postby Robski » Sun Nov 11, 2012 8:48 am

I cannot see any command in any of those captures therefore there will be no current flow, therefore load testing was not successful with a maths channel.So i am not surprised you're not seeing the correct feedback position voltage.

Take 3X channels on BM2/BL2/BD2, attach current clamp to either BM2/BL2 (correct polarity) & take a capture at engine off.

Then either blip the throttle watching the same channels or take for a road test through different load ranges of the engine, plenty of time on screen + sample rate & post the 2X captures, then we may get a good idea of what is going on.

The 14% & 30% figures are relating to duty cycle which can be checked afterwards.

NO CURRENT FLOW - NO VOLT DROP
User avatar
Robski
Advanced User
Advanced User
 
Posts: 602
Joined: Tue Sep 14, 2010 6:36 pm
Location: Yorkshire

Next

Return to Diagnostic discussion

Who is online

Users browsing this forum: No registered users and 0 guests