Peugeot 207 Vti crank no start ongoing issue

[max1]

Hi all, I am working through an issue with an ECT sensor problem & thought i'd introduce myself here.

First of all though I managed to contact member MikeT through this forum & he has kindly gone out of his way to come over to me & gone through some diagnostics with his diagbox software & we are progressing along ok. I offered him a small payment for his troubles but he refused & said donate to the forum instead. I don't have much to give but would like to donate a small amount, how do I donate please?

Car is 2009 Vti 1.4. Issue is a non start & code is P0118 - ECT fault, open circuit or short to positive. I had the common problem of coolant leaking from the ECT, this has now been replaced along with the connector but still no start. ECU plugs don't show any coolant ingress on a visual. With the ECT disconnected & ignition on ref voltage across the ECT signal & a known good ground is 3.3v, not 5v. Car is in eco mode which makes it difficult to safely disconnect the battery as you need the windows down for the correct procedure, however we have temporarily got around this. Next, with the battery disconnected ill test the cable from ECU to ECT to hopefully find the problem, i do have the autodata wiring diagram for the ECU pin outs. If I can't find a problem here will assume the ECU is faulty & take it from there. Key codes are good (car beeps if door is opened with keys still in)

cheers & thanks again to MikeT for the confirmation of ECT fault

[myglaren]

You can donate and/or buy forum stickers here:
https://www.frenchcarforum.co.uk/forum/donate

Welcome to the FCF

[MikeT]

It was a pleasure to meet you max1 and as I said, I get to benefit from the Diagbox practice so that's payment enough for me

In fact, that's the first time I've seen the diagbox screens, previously I've only been able to use the Lexia software so definitely a learning curve for me! As such, I know I wasn't as helpful as I could have been but blindly trying out the functions to see what relevant info it may provide would have taken up a lot of time, especially with such a slow netbook, maybe another time that's not a Friday evening. (btw, that was Rock N Roll I heard, a coffee shop or cafe round the corner was playing 50's music and a couple of girls were jiving outside along with a guy shuffling in his mobility scooter to Elvis's Mystery Train).

The fault code showed the ECT was reporting -40C and when we tried to start the engine, it did try to catch initially then just cranked. There are no other faults logged except an array of BSI issues which we assumed simply required a BSI reset. I did find Diagbox allowed us to over-ride the eco mode so we did a BSI reset which cleared most of those faults too.

Given the evidence, the question remains what does short or open circuit imply in this case? max1 says he's only measuring 3.3v from signal to earth, whereas autodata (I don't have Peugeot wiring diagrams access) states it should be 5v.
The loom to the ECU is pretty short (about half a metre) and well protected which will be checked in due course but it doesn't bode well as that leaves the ECU connectors (which max1 says looked clean) or the ECU itself?
Can the ECU be DIY-repaired? I have some surface-mount repair experience.

[max1]

Open would mean a break in either the signal or ground wires. Short to positive I assume would mean the 5v ref line is shorted somewhere.
With everything disconnected I checked the integrity of the wiring today & all checks ok with continuity & resistance (1.3 ohms end to end on signal & ground). Infinite resistance across signal & ground (no short). Looking possible I have a faulty ECU then. Am struggling to see why as all i have done is change the ECT sensor & its plug? One thing I didn't mentioned is that just after the initial non start, after disconnecting the sensor it did start ok but with fan blowing on full.

[MikeT]

I was curious if the circuit is isolated or possibly part of a larger circuit where the open or short could occur, ie part of the ECU internals and maybe even other connected circuits.

I believe the next logical test would be the ECU pins with the battery connected. If you want me over for any reason, just holler.

[max1]

Cheers Mike. Im pretty sure the grounds are shared throughout. Signal reference 5v Im assuming is supplied separately for each sensor, otherwise we would have seen other sensor faults?

Yes next thing is to either volt drop test the wiring under load or try to test the voltage straight from the ECU plug. I think ill try & de-pin the ECU plug somehow so i can probe right there. Will need the battery connected up again to do this though, so yeah I may have to give you a shout again for that once I'm ready with the wiring.

[MikeT]

The 3.3v reading is a concern, it's worth double-checking you got the right pins and to use the correct ground as it too needs testing, even though as you say they should all be common.

[wheeler]

The coolant can travel up the wiring harness into the ECU but you have said you checked it, it could be that the coolant has just not quite reached the ECU plugs yet but the coolant could be halfway along the wire causing a high resistance. Best to volt drop check the wire under load to confirm.
Also check the engine is not now flooded, this often happens with a faulty CTS as it can massively over fuel. Get the spark plugs out & heat them up with a blow torch & se if you can get it to fire up.

[max1]

Thanks. The car had been sat for about a week before we tried starting it, so I doubt any fuel was still on the plugs.

I've cut the ECT wires as close as poss to the ECU plug & measured voltage, still 3.3v so appears integrity of ECT to ECU wiring is good. Could still be a bad connection at the pins though.

Still have yet to load test the power & grounds to the ECU, will need a test light for this, not sure what bulb would load the cables properly though, thinking a 55w headlight bulb should do the trick?

Would have thought we'd have other fault codes as well though if ECU supply was bad?

If the load test is good then next would be to disconnect all other sensors one by one & monitor the bad reference voltage?

cheers

[max1]

MikeT, I had to cut the wires as I can't back probe this ECU plug, the holes on the back are completely snug with the wires & no way to get a t-pin in there, Peugeot seem to have kindly made it back probe proof!

[max1]

Any ideas on what sort of test light I should be using anyone ?

Thanks

[MikeT]

I think I now understand why you were considering de-pinning the plug.

I was hoping you could slip a needle or similar in there. Is it not even possible to pierce the wire insulation at the plug?
I don't like the idea of compromising insulation for obvious reasons but a pin prick seemed the lesser of the two evils in my mind, if necessary.

Due to the cost of replacement, I probably would have tried to probe the ECU pins with key-on first but thought it best to refer you here for more experienced advice.

I've since managed to get hold of the Peugeot wiring diagrams though I'm unsure of your car's specifications to ensure I can select the correct ones to refer to. Again, I'm happy to pop over again and provide what assistance I can.

[max1]

Thanks. Its not a big problem, I can solder the wires back together & cover with thick heat shrink & then re-wrap the harness to cover over. The fact remains I still have 3.3v directly from the ECU plug. (i had someone sit in the car to turn on the side lights, windows closed, when I reconnected the battery for this)

My options left now are to load test the ECU power & ground wiring by unplugging the ECU, then I can use a test light with a suitable bulb ( decent current draw) & probe the plug pins from the front, this should give me an idea of the wiring integrity. But like I said I'm looking for advice on what bulb rating i should use, I need to load/stress the wiring adequately. However seems unlikely to be a bad ECU power or ground as all other systems in the car seem to work fine, no other codes.

Only other thing i can think of after that is to disconnect the sensors one by one to see if one of them is pulling the reference voltage down on the temp sensor circuit somehow, perhaps the 5v reference circuit is shared across all sensors, i don't know. It wouldn't appear that way because the only code showing was the for temp sensor! I haven't checked the other sensors yet for a good ref voltage, perhaps i should but in the process its going to throw a load more codes no doubt.

Another thought is that there may be something else wrong that is a total coincidence but not showing a fault code, like the coil pack, thermostat or somnething. We did def clear that P0118 code & it came back right ?

Absolute bleedin mystery thus far

Thanks for your help

[MikeT]

I'm with you in hoping the ECU isn't the problem

Yes, we cleared the fault codes and carried out a BSI reset which also cleared most of the BSI related faults then finally read the INJ ECU fault codes once again to see the ECT fault has persisted.

This is the saved report from Diagbox (massively edited for brevity, believe it or not! )

Version of the copy : 4.02.03 Date and time : 2017-08-25 18:06:43

Type of vehicle 207
Vehicle Layout 207 CAN
VIN: VF3**************[VIN obfuscated, can be read by forum staff]
BUILD CODE NUMBER / RPO
Mileage 92888

Global test :
Date and time : 2017-08-25 18:08:23


ECUs present

BMF : Built-in Systems Interface
Response data
R61809664058780000696649833800603FFFF0A4052114799
R61B194000480210000000021240000
R61BA0800000000000000

State of the ECU: BSI
Reference 1 : 9664058780
Reference 2 :
Faults present : 9

F5FF : Unexpected re-initialisation fault coming from the BSI.
Characterisation : not characterised
Status :
Location : local
Variables associated with the fault


C98A : Engine relay unit : Fault Front right side light.
Characterisation : open circuit.
Status :
Location : local
Variables associated with the fault


C98B : engine fuse box: Front left side light fault.
Characterisation : open circuit.
Status :
Location : local
Variables associated with the fault


C98C : engine fuse box: Front right dipped headlamp fault.
Characterisation : open circuit.
Status :
Location : local
Variables associated with the fault


C98D : engine fuse box: Front left dipped headlamp fault.
Characterisation : open circuit.
Status :
Location : local
Variables associated with the fault


C98E : engine fuse box: Main beam headlamps fault.
Characterisation : open circuit.
Status :
Location : local
Variables associated with the fault


C98F : engine fuse box: Front left fog lamp fault.
Characterisation : open circuit.
Status :
Location : local
Variables associated with the fault


C990 : Engine relay unit : Front right fog lamp fault.
Characterisation : open circuit.
Status :
Location : local
Variables associated with the fault


C997 : engine fusebox : Fault in the horn control circuit
Characterisation :
Status :
Location :
Variables associated with the fault


ABRASR : Anti-lock Braking System (ABS) or Electronic Stability Program (ESP)
Response data
R6180966534448000099665344180FFFFFFFF100101FFFFFF

State of the ECU: ABSMK70_1
Reference 1 : 9665344480
Reference 2 :
Faults present : 0



AFFICHEUR : Multifunction screen
Response data
R61809645683880000296644839800810FFFF004058689199

State of the ECU: EMF_A
Reference 1 : 9664483980
Reference 2 :
Faults present : 0



AIRBAG : Air bags and pre-tensioners control unit
Response data
R618096540748800003966569968025520005034046595399

State of the ECU: SAC_AUTOLIV
Reference 1 : 9665699680
Reference 2 :
Faults present : 0



AUTORADIO : Radio
Response data
R618096650536770004966626697710010000004064960699

State of the ECU: AUTORADIO
Reference 1 : 9666266977
Reference 2 :
Faults present : 0



BSM : Engine relay unit
Response data
R618B9660376480000696649977800041FFFFFFFFFFFFFFFF

State of the ECU: BSM
Reference 1 : 9664997780
Reference 2 :
Faults present : 8

C98A : Fault : Front right side light
Characterisation : open circuit
Status :
Location :
Variables associated with the fault


C98B : Fault : Front left side light
Characterisation : open circuit
Status :
Location :
Variables associated with the fault


C98C : front right dipped beam headlamp fault
Characterisation : open circuit
Status :
Location :
Variables associated with the fault


C98D : front right dipped beam headlamp fault
Characterisation : open circuit
Status :
Location :
Variables associated with the fault


C98E : Driving lights fault.
Characterisation : open circuit
Status :
Location :
Variables associated with the fault


C98F : Fault LHF front foglamp
Characterisation : open circuit
Status :
Location :
Variables associated with the fault


C990 : Fault RHF foglamp
Characterisation : open circuit
Status :
Location :
Variables associated with the fault


C997 : horns control fault
Characterisation : open circuit
Status :
Location :
Variables associated with the fault




COMBINE : Instrument panel
Response data
R61809654567480000D96661326800C02FFFF014054435799

State of the ECU: COMBINE
Reference 1 : 9666132680
Reference 2 :
Faults present : 0



DIRECTN : Power steering
Response data
R61809684065180002196840651800068FFFF0F01FFFFFFFF

State of the ECU: DAE
Reference 1 : 9684065180
Reference 2 :
Faults present : 0



HDC : Controls under the steering wheel
Response data
R61809656421277000696657280770230FFFF004059072699

State of the ECU: HDC
Reference 1 : 9665728077
Reference 2 :
Faults present : 0



INJ : Engine management ECU
Response data
R61FE44A30000031918040901C81454180409FE02000001663941

State of the ECU: MEV17_4_EURO4
Reference 1 : 663941
Reference 2 :
Faults present : 1

P0118 : engine coolant temperature sensor signal fault
Characterisation : Open circuit or short circuit to positive
Status : Temporary fault
Location : local
Variables associated with the fault
Engine speed : 0 rpm
engine coolant temperature : -40 °C
vehicle speed : 0 kph
richness regulation status : Value invalid
Calculated charging value (filling) : 0 %
Quick richness correction (row 1) : 0 %
Slow richness correction (row 1) : -1 %




TNB : Seat belt not fastened warning lights unit
Response data
R61D79665103980

State of the ECU: TNB
Reference 1 : 9665103980
Reference 2 :
Faults present : 0


BSR : Trailer relay unit
Response data
R618D00000000000000000000000000000000000000000000

State of the ECU: BSR
Reference 1 : 0000000000
Reference 2 :
Faults present : 0



reading and clearing of faults
Date and time : 2017-08-25 18:23:26

CLRDTC_BTN
Date and time : 2017-08-25 18:24:29



Reading fault codes
Date and time : 2017-08-25 18:24:36


ECU : BSI
Response data
R5702C98DC990

Fault codes
C98D : engine fuse box: Front left dipped headlamp fault.
characterisation of the fault : open circuit.
cause : local

Variables associated with the fault


C990 : Engine relay unit : Front right fog lamp fault.
characterisation of the fault : open circuit.
cause : local

Variables associated with the fault





repair
Date and time : 2017-08-25 18:27:13



reading and clearing of faults
Date and time : 2017-08-25 18:27:22



Reading fault codes
Date and time : 2017-08-25 18:27:29


ECU : MEV17_4_EURO4
Response data

Fault codes
P0118 : engine coolant temperature sensor signal fault
Fault characterisation : : Open circuit or short circuit to positive
Status : : Temporary fault
from : : local

Variables associated with the fault

[max1]

Thanks for this Mike. Right at the end the variables are missing, do you know if they were still showing the same values ?