508 2.0 hdi engine warning light

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Leo1907
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508 2.0 hdi engine warning light

Post by Leo1907 »

afternoon folks, new member here so apologies in advance if the question has already been addressed - my warning light came on on my 508 2.0 hdi auto had it look at by a friend who said its fault code P2084 - which could be an exhaust gas temperature circuit range fault or particle filter temp sensor variation in voltage outside tolerance? the car still runs ok but its a bit disconcerting having the engine light on - it has gone off for a day or so a couple of times but returns - any help or advice would be greatly appreciated - many thanks in advance Steve

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GiveMeABreak
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Re: 508 2.0 hdi engine warning light

Post by GiveMeABreak »

We'll need your VIN (automatically masked from public view) in order to relate the fault code specifically to your engine management system.

Leo1907
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Re: 508 2.0 hdi engine warning light

Post by Leo1907 »

VF3**************[VIN obfuscated, can be read by forum staff] Thanks Marc

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GiveMeABreak
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Re: 508 2.0 hdi engine warning light

Post by GiveMeABreak »

Ok, so you have the 163 DW10CTED4 engine.

This fault is basically saying that the temperature readings are out of kilter:
Fault codeP2084
After sales description of the fault codeParticulate filter upstream gas temperature sensor: Voltage variation outside the tolerance
Description of the diagnostics
  • Electrical fault in the particle filter upstream temperature sensor
  • Variation in the temperature of more than 100 °C per second
Conditions of activation of the diagnosticsEngine running
Conditions of disappearance of the faultDriving with the engine hot for 5 minutes
Down-grade modes if fault presentDeactivation of the request for regeneration of the particle filter from the diagnostic tool
Switching on of the warning lamp and/or warning messageWarning lamp MIL
Main customer complaints likelyNo effects immediately perceptible to the customer
Suspect areas
  • Particulate filter upstream gas temperature sensor
  • Connector
  • Electrical harness
508 Upstream.PNG
The above is the particulate filter upstream gas temperature sensor and its role is to inform the ECU of the temperature of the exhaust gases.

It is a NTC (Negative Temperature Coefficient) resistance value "R" which changes in relation to the change in the temperature "T":
  • When the temperature "T" increases, the resistance value "R" decreases
  • When the temperature "T" decreases, the resistance value "R" increases
Minimum
Tolerance ( °C)
Temperature ( °C)Maximum
Tolerance ( °C)
Resistance ( kohms)
90 °C100 °C110 °C96 kohms
140 °C150 °C160 °C32 kohms
190 °C200 °C210 °C13,5 kohms
240 °C250 °C260 °C6,3 kohms
290 °C300 °C310 °C3,3 kohms
340 °C350 °C360 °C1,85 kohms
390 °C400 °C410 °C1,15 kohms
440 °C450 °C460 °C0,755 kohms
480 °C500 °C520 °C0,514 kohms
530 °C550 °C570 °C0,362 kohms
580 °C600 °C620 °C0,268 kohms
630 °C650 °C670 °C0,198 kohms
680 °C700 °C720 °C0,151 kohms
So I would check the connector first and if it is suspected as faulty then you have the information for a replacement.

1618KP is the part number, item 2 below in the parts diagram:
508 Upstream B.PNG

Leo1907
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Re: 508 2.0 hdi engine warning light

Post by Leo1907 »

thank you Marc, thats brilliant - i take it that its a job for a mechanic if your not very good at diy car repair!!

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Re: 508 2.0 hdi engine warning light

Post by Gibbo2286 »

There was a recall listed on some of the Citroens (Can't remember which exactly) where the harness had been badly routed and rubbed through on the hot exhaust, remedy was to replace the harness and re-route it.

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GiveMeABreak
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Re: 508 2.0 hdi engine warning light

Post by GiveMeABreak »

I think that was mostly on the Relays and a few other older vehicles - no recall listed for this on the 508, but worth checking that the probe is properly secured and the cable is not touching the exhaust.

Leo1907
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Re: 508 2.0 hdi engine warning light

Post by Leo1907 »

Will do lads - decided to try and have a look myself before going to a garage - I'll let you know how I get on - once again thanks for the info👍