2008 external temperature sensor erratic

[BarryC]

I’ve posted a message like this previously, and have also searched forums in UK re the 2008. The external temperature sensor that governs the heating and cooling sometimes (since the car was a year or so old, but now more frequently) shows temperatures around 3-5 deg C and then sometimes manages to climb up to ambient (around 20 C at the moment). Today, it’s refusing to budge above 5 degrees, when it’s 20 degrees outside. I’ve had this same issue a couple of isolated times earlier, in the earliest manifestation of it, the dealership cleaned a connector inside the door (I think) and in my most recent query with them about the same issue, the dealership “couldn’t find any fault codes”….. and left it at that.

I’ve read that the sensors can fail. I just wondered whether the sensor itself inside the mirror may be affected by dust (or a spider or something). Can the mirror glass be removed easily without damage, as I’d like to look at the internals of the mirror. I’ve found nothing on line specifically for 2008s (year 2017). Any advice gratefully received. I’m aware that the sensors themselves are probably fairly generic, and can be obtained on eBay fairly easily - however installation is not that simple for an amateur keen to not ruin the car‘s electrics In the process.

 

[dimistyle]

1 of our 308s does something similar but reads -9 deg and slowly goes up but only if i wiggle the rubber wiring harness with the door open.

I have previously disconnected the door connection between inside and the door. So guessing vibration loosening one of the pins.

Yet to work it out as car used daily.

Its somewhere to start before replacing the sensor

 

[BarryC]

1 of our 308s does something similar but reads -9 deg and slowly goes up but only if i wiggle the rubber wiring harness with the door open.

I have previously disconnected the door connection between inside and the door. So guessing vibration loosening one of the pins.

Yet to work it out as car used daily.

Its somewhere to start before replacing the sensor

Thanks for that. Yes, I’d forgotten that the dealership actually tried that one as the first solution - they fiddled with something inside the door and cleaned it(?). Whatever, I’ll remind them of that fact. That’s probably why they couldn’t find a fault code - because the sensor is ok, it’s just the connection somewhere around the door area that the problem. I’ll persist. Thanks. It’s quite unsatisfactory that they can’t cobble together a more permanent solution, if the connector is the problem. Seems a basic problem to fix permanently.

 

[pug407]

hi
just wonder if someone know where are the sensors in the peugeot 2008?
in the old Peugeot we used to have one inside on the dash, and one out side on the left mirror.
i would like to find out if by cleaning them i will be able to fix the strange behavior of my air condition on my Peugeot 2008.

 

[BarryC]

Thanks for that. Yes, I’d forgotten that the dealership actually tried that one as the first solution - they fiddled with something inside the door and cleaned it(?). Whatever, I’ll remind them of that fact. That’s probably why they couldn’t find a fault code - because the sensor is ok, it’s just the connection somewhere around the door area that the problem. I’ll persist. Thanks. It’s quite unsatisfactory that they can’t cobble together a more permanent solution, if the connector is the problem. Seems a basic problem to fix permanently.

A correction… the observed temperature can often start at minus degrees, and as it climbs upwards it shows all manner of road ice warnIngs!…….. While the external temperature is clearly in the teens. ”only doing its job”, one might say…..

 

[Doush_504]

 

[seasink]

There are OBD error codes for the ambient air temperature sensor - P0070 to P0074. These are invalid readings as seen by the BSI.

The readings are volts, so the BSI won't detect a resistance that produces a credible voltage - just produce a false display.

 

[BarryC]

There are OBD error codes for the ambient air temperature sensor - P0070 to P0074. These are invalid readings as seen by the BSI.

The readings are volts, so the BSI won't detect a resistance that produces a credible voltage - just produce a false display.

That explains the “no errors shown” by the dealership. Clearly some voltage is being registered, no matter how errant, so it seems”Ok”. Thank you for your clear reply.

 

[BarryC]

That explains the “no errors shown” by the dealership. Clearly some voltage is being registered, no matter how errant, so it seems”Ok”. Thank you for your clear reply.

An update.
the problem had reoccurred a number of times over the last few months, so I was eventually prompted to email the service department with an extended description of the problem and detailing their attempts at a solution. The dealership rang me back, and my car was booked in. They apparently checked the two connectors that exist between the sensor itself and the car‘s computer. It was done without charge - fair enough because the issue has existed ever since it was first noticed by me a year or so into its three year warranty.

after having had the problem occurring multiple times over past months, I got the car back and it worked perfectly. Outside temperature around 30 degrees, aircon came on as expected. Yay!

one week later: got in the car today. Started it from cold. Initial temperature shows -8 deg C (whereas outside temperature was around 27 deg C)….. temperature climbed up to ambient after about a minute or so, but not before blasting me with hot air for most of that time…..

maybe it’s the actual thermostat after all.

bloody frustrating that a cure hasn’t been found. I appear to be the only person having an issue, if the service department is to be believed. You might think I sound like a cranky old man. Pity it’s true.

 

[BarryC]

Errata

can‘t edit my post to remove two errors

I meant Temperature Sensor NOT thermostat
i didn’t start the car from cold when I got the heater blowing hot - I’d used the car an hour or so previously - hence the engine was already hot…… but the sensor still insisted it was -8 degrees outside. Inexplicable

PS
what does the edit function disappear? I had used it previously?

 

[Armidillo]

Errata

can‘t edit my post to remove two errors

I meant Temperature Sensor NOT thermostat
i didn’t start the car from cold when I got the heater blowing hot - I’d used the car an hour or so previously - hence the engine was already hot…… but the sensor still insisted it was -8 degrees outside. Inexplicable

PS
what does the edit function disappear? I had used it previously?

You get a few minutes to proof read and correct your post (or have 2nd thoughts about posting at all). I think this was introduced to prevent people who, for reasons known only to themselves, deleted posts that contained valid discussion and/or useful information - sometimes years later.

In essence, what you post (after that few minutes grace period) becomes property of the forum owner...