Can bad earth lead cause injection/fault codes?
Discussion
I'm guessing the answer to this is going to be a resounding yes! But here goes, sun was in the sky today, deciding to treat my little Meggy 225 to a gear oil change, after behaving itself after my steering rack woes.
Half way up the road Service light comes on and 'check injection'. And asr/esp light as a little Brucie Bonus.
Instinctually i whipped of the engine top cover and the battery earth lead where it meets the head was frayed a fair bit and generally looked rank!, years of this top cover rubbing against it i guess, would this trigger general random fault codes? I'm thinking yes?
Half way up the road Service light comes on and 'check injection'. And asr/esp light as a little Brucie Bonus.
Instinctually i whipped of the engine top cover and the battery earth lead where it meets the head was frayed a fair bit and generally looked rank!, years of this top cover rubbing against it i guess, would this trigger general random fault codes? I'm thinking yes?
I suppose it could be related to an electrical problem, but a poor engine ground connection would be more likely to cause weak starter motor performance than a running fault. It would be easy enough to connect a jump lead in parallel to see if the fault 'went away' but it does not seem very likely to me.
Is it possible you dislodged a wire while you were working around the gearbox? Some components would be earthed to the engine and a poor earth on an individual component could cause all sorts of problems.
Is it possible you dislodged a wire while you were working around the gearbox? Some components would be earthed to the engine and a poor earth on an individual component could cause all sorts of problems.
GreenV8S said:
I suppose it could be related to an electrical problem, but a poor engine ground connection would be more likely to cause weak starter motor performance than a running fault. It would be easy enough to connect a jump lead in parallel to see if the fault 'went away' but it does not seem very likely to me.
Is it possible you dislodged a wire while you were working around the gearbox? Some components would be earthed to the engine and a poor earth on an individual component could cause all sorts of problems.
All i did regarding gearbox was drain oil and fill it again, most technical thing i did was stick filling tube down by battery to fill gearbox, wasn't near any wiring etc.Is it possible you dislodged a wire while you were working around the gearbox? Some components would be earthed to the engine and a poor earth on an individual component could cause all sorts of problems.
As soon as check injection warning comes up car goes into limp mode. Car ran perfectly before oil change, really odd? Im really hoping it's just earth cable.
Only other thing i've done was fit a new 075 60ah Lucas battery 2 days ago. But as i said, car ran fine today.
Time line is not entirely clear. I think you said:
Did you maintain ECU power during the change?
What fault codes does your ECU record now? (You would need an OBD2 reader to know this, but they're cheap.)
- new battery fitted two days ago
- long journey today, car drove well and no fault indicator
- gearbox oil replaced
- dashboard shows fault indicators and car drives badly
Did you maintain ECU power during the change?
What fault codes does your ECU record now? (You would need an OBD2 reader to know this, but they're cheap.)
GreenV8S said:
Time line is not entirely clear. I think you said:
Did you maintain ECU power during the change?
What fault codes does your ECU record now? (You would need an OBD2 reader to know this, but they're cheap.)
Yep, that's the timeline. I replaced the battery as a) it's a new car to me and i was preparing for winter, plus b) Don't know if it was my imagination but alternately it would crank over 'slightly' slower sometimes, then somedays a bit quicker, so i replaced it.- new battery fitted two days ago
- long journey today, car drove well and no fault indicator
- gearbox oil replaced
- dashboard shows fault indicators and car drives badly
Did you maintain ECU power during the change?
What fault codes does your ECU record now? (You would need an OBD2 reader to know this, but they're cheap.)
Regarding codes i do have an obd2 reader but it wouldn't communicate with ecu, must be different version. Also used torque app to read but found nowt.
Theres a French car specialist nearby, i'll get him to read it. Im intending to buy Renault clip software soon anyway.
Did you maintain power to the ECU while you replaced the battery? It's not strictly necessary but if you didn't do it, that might have prompted the ECU to reset some of it's learned settings and test results hence needing more initialisation and learning subsequently. Some fault codes will come up if the ECU completes a certain number of drive cycles without passing specific tests so it's possible that some of the symptoms you're seeing are a delayed consequence of that battery replacement.
Renault wiring and connectors are f
king horrendous. I would hazard a guess at one of the multiplugs being green and furry inside or a bit of loom being chafed and it has only taken a slight disturbance to upset it. Get a can of electrical contact cleaner and conformal coating and clean inside all the connectors and inspect all the loom. Deffo repace that earth too. When its all working spray it with conformal coating.
king horrendous. I would hazard a guess at one of the multiplugs being green and furry inside or a bit of loom being chafed and it has only taken a slight disturbance to upset it. Get a can of electrical contact cleaner and conformal coating and clean inside all the connectors and inspect all the loom. Deffo repace that earth too. When its all working spray it with conformal coating.GreenV8S said:
Did you maintain power to the ECU while you replaced the battery? It's not strictly necessary but if you didn't do it, that might have prompted the ECU to reset some of it's learned settings and test results hence needing more initialisation and learning subsequently. Some fault codes will come up if the ECU completes a certain number of drive cycles without passing specific tests so it's possible that some of the symptoms you're seeing are a delayed consequence of that battery replacement.
Yep, sounds about right. It definetly feels like a delayed reaction to something, definetly isn't an instant result from changing bloody gearbox oil, never touched 'anything' electrical at all!Even changing a battery is just taking off two terminals, and it ran fine for a couple of days afterwards.
Well, 9 minutes past 6 on a Sunday morning,wide awake for hours don't think i've ever had a car i've lost sleep over! , anyway, in middle of Haynes manual about battery disconnection it says nothing special about battery disconnection precautions.
However, in the reference sections in the back it mentions it could fk up your car from a simple thing like disconnecting a sodding battery,says to start car, try and run it as close to idle speed until warm, then run at 1200 rpm for 2 minutes, then 5 minutes of normal driving.
I did notice when in in limp mode it idled higher than norm so i'll give this routine a go until i get codes read.
Thank god my little Peugeot 205 is there, never lets me down when an emergency crops up! :-)
However, in the reference sections in the back it mentions it could f
k up your car from a simple thing like disconnecting a sodding battery,says to start car, try and run it as close to idle speed until warm, then run at 1200 rpm for 2 minutes, then 5 minutes of normal driving. I did notice when in in limp mode it idled higher than norm so i'll give this routine a go until i get codes read.
Thank god my little Peugeot 205 is there, never lets me down when an emergency crops up! :-)
Just incase anyone else gets these symptoms, a quick update. I got rac guy out who confirmed my thoughts about the frayed earth lead from neg terminal to cylinder head. I renewed it yesterday and cars perfect!
Years of the engine top cover being whipped on and off was putting pressure on the lead at the engine end and just wore it out!
Years of the engine top cover being whipped on and off was putting pressure on the lead at the engine end and just wore it out!
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