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Aug 24th, 2023
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Joined: Aug 2013
Posts: 3,383 Likes: 13
Talk Morgan Addict
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Talk Morgan Addict
Joined: Aug 2013
Posts: 3,383 Likes: 13 |
Disconnecting the battery or switching off all power and leaving it and putting it back on again will fix nothing that’s an old school fix for early ECU’s with EPROMs. For over 20 years cars ECU’s have used E2PROM’s (difference is they now use Electronically ERASABLE Programable Read Only Memories) tats why you use your code reader to read and then delete the codes.
If it were mine I would read all codes make a note then delete them then leave your code reader on and go to monitor values go for a drive and see if it collects anything strange but I strongly suspect it will read nothing and the light will stay off and then randomly one day it comes back on and you just go through the process of read notes and delete again as the car will be running perfectly.
We had an issue at Volvo Cars with one of the engine types where on start up depending where the crankshaft stopped it was possible for it to kick back a few degrees before the signal was received and install a code that the flywheel sensor signal was missing of course it wasn’t, the car runs perfectly by referencing the camshaft signal took us a long time to find that one!
Good luck but I suspect as Graham said it’s a brain fart in the ECU
Br
Colin Hi Colin, It seems to remember a Green Plus 8, isn't it ? BR 👍
BR Colin
Who used to be a Spanner Juggler
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Joined: Nov 2015
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Just barreling along Talk Morgan Guru
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Just barreling along Talk Morgan Guru
Joined: Nov 2015
Posts: 7,910 Likes: 242 |
Colin, I like the 'brain fart in the ECU'  we all suffer that sometimes !
Jon M
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Joined: Jul 2007
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Member of the Inner Circle
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Member of the Inner Circle
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Posts: 26,759 Likes: 424 |
I do. Especially now there is some much to think / worry about.
JohnV6
2022 CX Plus Four
2025 MG ZS EV aka Trigger
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Joined: Nov 2011
Posts: 41
Just Getting Started
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OP
Just Getting Started
Joined: Nov 2011
Posts: 41 |
Thanks Colin. The thing is , the car isn't running properly , but I think ill check all the earths, continuity as a starting point . do you know if any of the sensors share any supplies / earths in common . Or any good places to start on the electrical side with regards to cabling / connections on the ECU itself , or any fuses that could relate to this issue . I cant help thinking that the recent wet weather may have had something to do with it
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Joined: Sep 2011
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Member of the Inner Circle
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Member of the Inner Circle
Joined: Sep 2011
Posts: 14,723 Likes: 149 |
I had a mysterious problem with an ECU that was eventually resolved by unplugging and replugging the ECU several times. If some contact cleaner had been available a spray inside the male and female connector probably would have helped. Turned out that there was a bad (dirty?) contact between one of the connectors in the plug and the ECU. Before that we tried everything else including emptying the fuel tank and fuel bowls.
Peter ![[Linked Image]](http://bradley.it/public_images/drive.jpg)
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Joined: Nov 2015
Posts: 7,910 Likes: 242
Just barreling along Talk Morgan Guru
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Just barreling along Talk Morgan Guru
Joined: Nov 2015
Posts: 7,910 Likes: 242 |
RD&G, have you checked your battery voltage, both static & under load whilst cranking ?
Although many last longer, a 2016's battery may be failing
Jon M
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Joined: Aug 2013
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Talk Morgan Addict
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Talk Morgan Addict
Joined: Aug 2013
Posts: 3,383 Likes: 13 |
Sorry wrote a great long reply on this iPhone then someone rang with a Mini gearbox question and I lost your reply. Excellent points above, all are valid. Plugging and unplugging and a squirt of contact cleaner in every plug and connector is very good advice. As is checking earths especially ECU multiplug connectors.
Advanced check is to inspect every pin and socket looking for black spots (arcing of low voltage connector remember some only carry 0.8-1.5v) and loose sockets or pins pushed back into the block connector.
Electrics are a bugger to fault trace but don’t forget the basics, battery and running voltages, fuel line pressure, and note all monitor values with your code reader, if it can’t read them there are excellent ones that can for just a few pounds.
You will crack it and what a great learning curve.
BR
Colin
BR Colin
Who used to be a Spanner Juggler
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Joined: Feb 2016
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Talk Morgan Guru
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Talk Morgan Guru
Joined: Feb 2016
Posts: 7,940 Likes: 218 |
Thanks Colin. The thing is , the car isn't running properly , but I think ill check all the earths, continuity as a starting point . do you know if any of the sensors share any supplies / earths in common . Or any good places to start on the electrical side with regards to cabling / connections on the ECU itself , or any fuses that could relate to this issue . I cant help thinking that the recent wet weather may have had something to do with it All four cam and crank position plus knock sensors connect directly to the PCM (powertrain control module). The four camshaft control solenoids share a common positive supply via fuse 13 (15 amp) in engine fuse box, in turn fed by the PCM main relay, triggers are on negative side from PCM. This common supply connects to the solenoids via a single cable connector C58 in the engine loom, with white/yellow cable from relay and light green cable out to solenoids (there is a splice in this single cable to feed all four solenoids plus evap cannister purge valve). A few common sources to check therefore.
Last edited by Richard Wood; 31/03/20 07:57 PM.
Richard
2018 Roadster 3.7
1966 Land Rover S2a 88
2024 Royal Enfield Guerrilla 450
1945 Guzzi Airone
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Joined: Nov 2011
Posts: 41
Just Getting Started
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OP
Just Getting Started
Joined: Nov 2011
Posts: 41 |
Thanks for the feedback Richard, funnily enough I looked at the wiring diagrams (which only seem to show the downstream sensors!), but I noticed that fuses 13 and 14 seemed to be a common factor. So the first thing I looked at today was fuse 13 and guess what it was blown. I replaced it and it blew again. So I am in a way quite relieved as the obvious common problem seems to be a great starting point. So my question is could this be a shorted heater circuit - does that happen?? or do you know of any obvious places to look to trace the short? Thanks again
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Joined: Sep 2011
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Member of the Inner Circle
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Member of the Inner Circle
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Posts: 14,723 Likes: 149 |
Perhaps when the O2 sensor was changed the wiring was damaged. A very good mechanic that I used to know always used to say "start from the last thing that you changed" 90% of the time he was correct.
The first thing I would check is the wiring leading to the O2 sensors , particularly where it crosses any body work. If nothing is obvious I would try simply disconnecting from the sensors, in case there is some weird problem with one of the sensors.
Peter
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