[scoey1001]

Car - 2008 207

Engine - 1.4 VTI (EP3)

Background - Had error message 'stop engine temp too high' even when starting from cold. Temp gauge shoots up but when this sensor/connector is removed it drops. Been into peugeot and the parts guy had a look under the bonnet then brought his diagrams up (searching via reg. number) and according to peugeot it doesn't exist! Also that i would have to book it in...which didn't go down too well.

P.S it isn't the coolant/temp. sensor which sits on top of the thermostat housing (held in by the green clip which you can see in the photo).

Any help much appreciated.

 

[noddy-hol]

HI...that doesn't look like a factory crimp connector...what it does I cant help...perhaps it has 2 temp sensors and this one has failed?

 

[Ian Mallett]

Not sure what it is but that connector does not look like a factory fitted one. Where does that blue wire go?

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[scoey1001]

Now found out this is the oil pressure switch! So god knows how disconnecting it made the temp needle drop. Really puzzled now. And no it's been tampered with at some point. Gonna try and get a scrap one.

Blue wire into the grey oil pressure switch Ian.

What you said about 2 temp sensors though apparently in the haynes it says this engine has an additional wiring connector for the electric thermostat. But where this additional one is i now don't know (as i thought this was it)

 

[Ian Mallett]

If the oil switch has failed or wiring is bad it could be shorting and causing false reading on temp. Check engine earth strap too

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[scoey1001]

Cheers Ian will do. Hopefully once i get the connection sorted this will solve it.

my air con went about the same time as i got these error messages regarding engine temp do you think they could be related? had a purge and regas and its still not kicking in. Also we tested and found that no power was getting to the compressor. My gut is that is all electrical related somehow?

 

[Ian Mallett]

I'd say it's possible. Stick a jumplead on battery negative and onto engine somewhere & see what happens

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[scoey1001]

Got the connection sorted but still getting the same problem. Temp gauge straight to max and STOP message. Also got 2 codes relating to coolant sensor (PO117 & PO119) which i replaced a couple of weeks ago. The codes i had relating to the thermostat (PO597 & PO598) haven't come back yet.

Couldn't do what you recommended as i couldnt get any jump leads.

So totally stumped now. Any ideas welcome.

 

[Ian Mallett]

If the problem has started since the coolant sensor was replaced I'd be tempted to try another one, or if you still have it, plug the old one back in and see if there's any difference.

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[Ian Mallett]

If I unplug the temp sensor on my expert I get this same thing, max temperature, stop light, overheat light & engine fans. It could therefore be a dodgy sensor, broken wiring, bad connection in the plug or even just not plugged in properly.

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[wynb]

On our 807 this overheating warning comes up occasionally within 2 miles of setting off (the engine clearly is still cold), continuing to drive results in gauge dropping like a stone a minute or so later, think it is a feature of the sensor or maybe a lazy thermostat.

 

[scoey1001]

This warning doesn't go off just stays constant no matter how far i drive.

Just shorted out the coolant sensor and the warning still appears so can rule that out. However codes PO117,PO119,PO597 & p0598 have now all gone to be replaced by PO118 (also coolant sensor).

Just seems like a problem with the ecu sending things crazy. May have to get an auto electrician in or something as i'm a bit stuck now. Frustrating as it doesn't actually seem to be affecting the running of the car etc. just the temp gauge.

 

[reliable406]

You cant short out the sensor to test it it wont make any difference your problem IS the sensor or the wiring between the sensor and the ecu pull the plugs check for water ingress at sensor AND ecu.

 

[scoey1001]

Hi so as my father in law was running the diagnostic etc. He left the passenger door open and when he tried to start the engine it did nothing. Recharged battery and started again and the gauge is working as it should with no warnings etc.

Also whilst battery was recharging we unplugged ecu and sensor and checked for water/corrosion. All looked perfectly fine.

Just got to pray codes don't come back but looks like I need a new battery. Not sure if it was this or unplugging ecu that has stopped the problem. Albeit I wouldn't be surprised at all if it comes back.

Air con still not functioning though. will keep you updated.

 

[scoey1001]

Just going back to the air con, is there any further tests i can do at home to try and diagnose the problem? So far tried purge and regas and changing the air con pressure switch. Or is it time to hand over to a professional?

*edit - further reading makes me think it might be the thermostat. is there any way to test?

 

[Ian Mallett]

Regarding temp gauge, fingers crossed it was a bad connection somewhere, or the way needed resetting to realise it had a new sensor in.

Regarding air con, does anything happen when you switch it on, any engine fans on? Have you checked all fuses?
With engine & ignition off apply 12v to the live terminal of the compressor clutch plug (on top of the compressor) if clutch gives a nice sounding clunk then it is working, if it doesn't then that's your problem. (Either bad clutch or bad wires at the compressor) ive seen loads where the wires have broken or corroded on top of the compressor.

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[scoey1001]

Hi Ian, yes my feeling was it needed some kind of reset and unplugging ecu did this?

Thanks I will try what you said later today. Reason I say thermostat though is because codes po597 and po598 keep returning. And no nothing happens. The display works and fans but the clutch does not kick in at all.

 

[scoey1001]

And yes checked all fuses.

 

[scoey1001]

Hi Ian, hope you can help!!

We tested either side of the yellow switch shown in the picture and there was current either side. Also tested for continuity at the coil which there was. But still the clutch plate not turning?

The temp gauge and STOP ENGINE TEMP TOO HIGH has also returned (thought it was too good to be true) along with codes for thermostat. When you clear them the error message goes but comes back.

Had the garage who does my company's vehicles look at both issues this morning and they said it was a bit out of their depth and recommended an auto electrician. The only thing they could tell me was from live data the car thinks the coolant temp is way above what it should be! So basically nothing I didn't already know.

Still don't know if the two are related and can't work out why if power seems to be there why is the clutch not kicking in?

Any help much appreciated.

 

[reliable406]

High engine temp will cut aircon i believe but you do have more than 1 problem they are related but not likely the same thing causing both unless its wiring to a common earth point