foxy99
Posted a lot
Posts: 1,380
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Jan 18, 2024 21:14:25 GMT
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Any boffins out there that can help with this? I have a 56-plate Mondeo 2.2 which only has one EML/MIL issue and it's all EGR-related. I've fully-dismantled and cleaned 2 (aftermarket) EGRs so I know the plunger isn't stuck and there are no broken pins or teeth in the mechanism but they are both throwing-up same/similar codes which point towards problems in the sensor-circuit or 'A' circuit. I'm getting P0403, P0405 and P0409. Looking at resources online it seems that sometimes these are due to broken wires or similar so I'd like to check what Ohms or V readings I should be getting on the various wires/pins It seems that the colour-coding for the wires going to pins 2, 4 & 6 is consistent regardless of age or make (Ford or Jaguar) and these are the ones for the sensor-circuit. Using a variety of resources I've found that: - #2 (brown/blue) is the sensor-ground
- #4 yellow/blue is the sensor-supply
- #6 white/blue is output
On various YouTube videos I've seen they probe about in the back of the plug looking for a 5V 'reference' wire and it seems to be the middle one so, on mine that would be the #4 yellow/blue 'sensor-supply', which seems to make sense. I've no idea what you'd expect to find on the other two. Does 'output' (#6 white/blue) perhaps mean this wire feeds voltage to the wire(s) which go to the motor in the EGR? Reason I ask that is that seems to be no connection with #1 pin and the motor-terminal on that side of the EGR when checked with Ohmmeter  getting this code on my OBDII reader when EML shows on dash EGR opened for inspection/cleaning these terminals go to tabs on the EGR motor and (appear to) lead to pins #1 & #5 on EGR socket  pins in EGR sockets. L-R (top rows) are #6, #4, #2 & (bottom rows) are #5, #1  EGR plug from my car (56 plate 2.2) wiring for EGR from Jaguar manual with corrections to wire-colours for #5 & #1  meaning of the symbols in the EGR schematic EGR wiring appears to lead to this connection to PCM. thinking of separating this connector to take continuity readings on the 5 wiresI also took resistance readings from the EGR-socket pins (with EGR on bench) and am not sure what they tell me. - pins #2 #4 #6 all connected to each other (showed continuity) with slightly different Ohms values
- pin #5 showed zero resistance when connected to the terminal that goes on the motor on same side
- pin #1 showed no continuity with the motor-terminal
- pins #1 & #5 showed no continuity with #2,#4,#6
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Last Edit: Jan 27, 2024 23:02:46 GMT by foxy99
1974 Daimler Double-Six VDP
1965/67 Hillman Imp pick-up
1984 VW Polo breadvan
1970s Yamaha Twins (4)
1976 Honda SS50ZK1
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jimi
Club Retro Rides Member
Posts: 1,816 
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Jan 19, 2024 12:41:44 GMT
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What about the actual sensor ? Have you tested that ? Normally workshop manuals give you expected sensor values/voltages for testing purposes.
It's very unlikely that the sensor drives the motor directly, more likely that the sensor signal goes to the electronic module and that drives the motor. Without having a circuit diagram for electronic module the resistance tests don't tell you anything meaningful.
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Black is not a colour ! .... Its the absence of colour
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foxy99
Posted a lot
Posts: 1,380
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Jan 19, 2024 15:21:13 GMT
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Thanks jimiSince creating this thread I've found some more info... AFAIK the sensor-circuit is in the EGR-plug and the 3 wires (#2, #4, #6) control that. I'm going to check the values today (on the wires) with the ignition on, using Voltmeter. Someone told me the electrics inside the EGR-cover can break-down so if the wiring is ok I'll get a new cover. You can get them from Ford for about £30  diagram of EGR and pins more detailed diagram of electronics inside the EGR-cover |
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Last Edit: Jan 19, 2024 22:41:30 GMT by foxy99
1974 Daimler Double-Six VDP
1965/67 Hillman Imp pick-up
1984 VW Polo breadvan
1970s Yamaha Twins (4)
1976 Honda SS50ZK1
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Jan 19, 2024 20:59:21 GMT
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Check that the female sides of the plugs are nice and tight on the male side
We had an issue at work with something similar and it turned out the contacts had opened up so not giving the correct readings
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foxy99
Posted a lot
Posts: 1,380
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Ok so I did my checks tonight on the plug to the EGR (disconnected and ignition on).
#4 got exactly 5V
#6 got 0.3V which was correct per a YouTube video
#2 got nothing
#1 got 0V
#5 got 4v
The readings I got seem to look good so I'm pretty sure I don't have a problem with my wiring now but I can't yet test anything to see if values fluctuate when revving the car as I didn't manage to back-probe the plug. There's no metal showing around the wires so am going to need something sharper than what I used tonight.
Also just seen a video on YouTube where the guy energised the solenoid (pins #1 & #5?) with a 12V battery then took various Ohms readings on the other pins which I didn't follow.
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1974 Daimler Double-Six VDP
1965/67 Hillman Imp pick-up
1984 VW Polo breadvan
1970s Yamaha Twins (4)
1976 Honda SS50ZK1
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foxy99
Posted a lot
Posts: 1,380
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If anyone is interested I took some more readings - from 2 different EGR-covers (same type) and find that there was a problem with the one I originally checked... Going back to (bottom part of) my post from 18th Jan I found that there should be continuity at pin #1 (which is +VE to open valve) Basically I pulled the plug off a spare cover and found that up to the plug there was continuity at pin #1, just like the one on other side (#5). There was also continuity between the pin in the plug and its spade on the other side so there must have been a bad connection between the spade and the circuit in the cover. This made sense to me as I'd been wondering all for days why one side would be different to the other. Anyway, after that, with the cover back on there was continuity between pins #1 & #5 (via the motor) and touching them with a 12V supply caused the EGR valve to work. So prior to this is't not surprising I was getting a fault code as there was no flow thru the motor. So I thought my problems were solved and got ready to swap this EGR for the other duff one on the car but then the valve stopped working when 12V was applied to the plug-pins so I assumed I'd burned the motor out or something . I topk the cover off again and the motor still works fine when 12V applied. Anyway that's enough info for just now and I have ordered an new cover but I can't understand what happened except to say that the plug should have a spring-loaded plastic pin on the back which rests on the end of the EGR valve. I found this out when I pulled the plug off the other EGR. My brain is a bit fried with this right now   plug removed from cover checking continuity of cover-terminals via motor there was issue with break in continuity from spade on RHS to its track inside cover plug removed from another cover clearly shows plastic pin broken/missing from first one pin is spring-loaded plastic pin contacts top of EGR valve so moves up and down affecting signal when valve moves (or vice versa perhaps)NB I forgot to say the plug on the 2nd cover was showing different issues... it had continuity thru #1 & #5 but there was no continuity between the other pins (#2, #4, #6). |
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1974 Daimler Double-Six VDP
1965/67 Hillman Imp pick-up
1984 VW Polo breadvan
1970s Yamaha Twins (4)
1976 Honda SS50ZK1
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foxy99
Posted a lot
Posts: 1,380
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I can't really remember now chronologically all the steps I went thru and the readings (Ohms/Volts) I took on what wires and pins but fwiw I'm pretty sure my wiring is fine. I'm also confident that all Euro IV Mondeo EGR issues are to do with fried electronics in the cover. Well the plug attached to the cover. I was getting different continuity readings on the 2 used covers I had and ordered a new Ford one. I took readings on that which seemed to make sense (per the values in the schematic posted earlier) altho there are only 2 values in that and there are 3 readings due to there being 3 pins. The values are 2K2 (2200 Ohms) and 1K5 (1500 Ohms) With the new cover on I'm not getting any codes on OBDII tool (yet) Dismantling the plugs further you can see two different types of electronics. One uses a magnet atop the plastic pin which passes something on the little circuit-board. The other uses a brass contact with tiny fingers. I had some success getting my Ohm-meter needle to move while simulating the contact passing over its circuit-board  new EGR cover  1600(?) Ohms  1500(?) Ohms  2400(?) Ohms  electronics inside one EGR plug  moving contact from this plug has a magnet in it  different type of moving-contact in other EGR plug |
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1974 Daimler Double-Six VDP
1965/67 Hillman Imp pick-up
1984 VW Polo breadvan
1970s Yamaha Twins (4)
1976 Honda SS50ZK1
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if Ford are selling just the cover it sounds like a known issue
good diagnosis work
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foxy99
Posted a lot
Posts: 1,380
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Thanks redratbikeYes. I think it's a known issue that has been forgotten about  Weird thing is the cover doesn't have its own part-number. I only found it when searching under the part-number for the full EGR. IE the number on the Ford parts-list for the EGR is also the number on the box for the cover |
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Last Edit: Jan 30, 2024 19:03:53 GMT by foxy99
1974 Daimler Double-Six VDP
1965/67 Hillman Imp pick-up
1984 VW Polo breadvan
1970s Yamaha Twins (4)
1976 Honda SS50ZK1
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