Page 1 of 2
temp reading raise but ECT sensor drop ???
Posted: Wed Oct 16, 2013 12:00 pm
by bl4ckclio
as topic
2004 Peugeot 406 EW10J4 Auto
when scanning with PP2000 -> Engine ECU Test -> Injection -> Parameter -> coolant temperature
something strange I see.
when first start the engine, gauge reading about 40->50->60 C, I see coolant temp show above 60 C.
engine warmer, about 80 C, PP2000 parameter show the engine coolant temp below 60, about 55 C
when gauge hit about 90 C, parameter coolant temp show 48 C.
I see on screen PP2000, constrain for coolant temp should between 80-110 C.
Bought new genuine coolant temp, replace the old ones, show the same !!!!
trace the wiring from ECT connector to engine ECU....nothing wrong.
I feels heavy acceleration at low RPM which I think maybe to rich.
my MPG about 17,3L/100km.
what should I have to do, Mates????
thanks in advice, Cheers.
Re: temp reading raise but ECT sensor drop ???
Posted: Wed Oct 16, 2013 1:21 pm
by jasper5
Have you replaced the engine management coolant sensor or the engine coolant sensor?
The engine management coolant sensor is what you should replace.
Re: temp reading raise but ECT sensor drop ???
Posted: Wed Oct 16, 2013 1:45 pm
by bl4ckclio
jasper5 wrote:Have you replaced the engine management coolant sensor or the engine coolant sensor?
The engine management coolant sensor is what you should replace.
yes, which I have replaced is engine management sensor.
it's a green one.
p/n 1338A7 base on servicebox.
Re: temp reading raise but ECT sensor drop ???
Posted: Wed Oct 16, 2013 5:43 pm
by steve_earwig
bl4ckclio wrote:17,3L/100km
That's about 16mpg, appalling
SEDRE says green connector too
No other faults logged?
Re: temp reading raise but ECT sensor drop ???
Posted: Thu Oct 17, 2013 4:38 am
by bl4ckclio
steve_earwig wrote:bl4ckclio wrote:17,3L/100km
That's about 16mpg, appalling
SEDRE says green connector too
No other faults logged?
PP say no fault found

Re: temp reading raise but ECT sensor drop ???
Posted: Thu Oct 17, 2013 1:18 pm
by Doggy
Could you possibly have an airlock in the region of the sensor - (it'll read cold if it's not immersed in coolant)?
Re: temp reading raise but ECT sensor drop ???
Posted: Fri Oct 18, 2013 10:44 am
by bl4ckclio
Doggy wrote:Could you possibly have an airlock in the region of the sensor - (it'll read cold if it's not immersed in coolant)?
thermostat stuck closed?
but the Tstat housing hot enough to transfer heat to ECT sensor....?
but I'll try to bleeding the coolant.
wanna ask mate,
so temp gauge, engine management, and fan are controlled by this sensor only?
no other?
Re: temp reading raise but ECT sensor drop ???
Posted: Fri Oct 18, 2013 11:39 am
by steve_earwig
bl4ckclio wrote:but the Tstat housing hot enough to transfer heat to ECT sensor....?
Unless it's insulated from the housing...
You should be able to tell if the thermostat has opened as the radiator & pipework will suddenly get a lot hotter.
bl4ckclio wrote:so temp gauge, engine management, and fan are controlled by this sensor only?
no other?
The fan is also controlled by the pressostat (I don't know either but the diagram shows it somewhere about the ecu end of the radiator)
I'm quite hopeful of the airlock suggestion, mainly because we otherwise got nothing

Re: temp reading raise but ECT sensor drop ???
Posted: Fri Oct 18, 2013 12:45 pm
by Doggy
steve_earwig wrote:The fan is also controlled by the pressostat (I don't know either but the diagram shows it somewhere about the ecu end of the radiator)
I think that's how rad fan overide for when aircon's running works on earlier, semi-mux cars. On this 2004 vehicle, aircon control is handled by the engine ecu, which operates the compressor clutch and rad fan as necessary. The pressostat is replaced by an analogue pressure transducer, (which looks the same), - at least that's what happens on HDi's.
Re: temp reading raise but ECT sensor drop ???
Posted: Fri Oct 18, 2013 3:30 pm
by steve_earwig
Hey, it's what's on the wiring diagram, maybe they didn't bother changing the name. I dunno what's inside it but it has 3 wires, all heading into the ecu.
Re: temp reading raise but ECT sensor drop ???
Posted: Sun Oct 20, 2013 1:19 am
by bl4ckclio
allright,
after my car sat down for 2days, I try to diag before started it (cold engine)
outside temp show 21C, the coolant temp 70C and air temp 55C ........???
so I think both coolant and air temp are false.
not only coolant temp.
any suggest?
Re: temp reading raise but ECT sensor drop ???
Posted: Sun Oct 20, 2013 8:25 am
by steve_earwig
Is that inlet air temperature?

Re: temp reading raise but ECT sensor drop ???
Posted: Sun Oct 20, 2013 8:46 am
by Doggy
Probably - unplug the MAF and see if you lose the reading.
Re: temp reading raise but ECT sensor drop ???
Posted: Sun Oct 20, 2013 11:16 am
by bl4ckclio
steve_earwig wrote:Is that inlet air temperature?

yes.
Re: temp reading raise but ECT sensor drop ???
Posted: Sun Oct 20, 2013 1:58 pm
by bl4ckclio
Doggy wrote:Probably - unplug the MAF and see if you lose the reading.
MAF=Mass Air Flow...??
there isn't on EW10.
