Peugeot 207 Vti crank no start ongoing issue

[MikeT]

Actually, reviewing the video, go to timestamp 18:25 and then read the correction he's put about shared grounds.

The video I'm looking for expands on this in detail to clarify.

[MikeT]

Meanwhile, this is what I was hoping could be tested, from timestamp 37:40 though this actually is a bad ECU.

[max1]

Actually, reviewing the video, go to timestamp 18:25 and then read the correction he's put about shared grounds.

The video I'm looking for expands on this in detail to clarify.

Yeah looks like there is a possibility the 5v could be shared with another thermistor like the IAT sensor. I have asked the question over at the scannerdanner thread.

[MikeT]

Actually, reviewing the video, go to timestamp 18:25 and then read the correction he's put about shared grounds.

The video I'm looking for expands on this in detail to clarify.

Yeah looks like there is a possibility the 5v could be shared with another thermistor like the IAT sensor. I have asked the question over at the scannerdanner thread.

What scannerdanner shows us is that the ECU's he's testing (ok, it's the US market so maybe irrelevant) can share these references internally, despite showing them as seperate ECU pins and circuits on the external diagrams. Wish I could find the diagrams for your ECU to know for sure.

[MikeT]

Just read Tyler's clarification so seems it was a red herring and I can't re-find the video I wanted, sorry max, I have no more suggestions.

p.s. What's the plan, are you going to replace the ECU and hope for the best?

[MikeT]

scanner danner is the dogs when it comes to automotive if you can understand everything he is saying, the guy has some serious knowledge, I think when dealing with petrol engines I think an oscilloscope is a must though, I hope to order one this month for an ongoing project car.My lexia doesnt have a measuring card and my wurth WOW and Delphi clone only read some systems.

It's certainly helped me in this quest though like us all, he's prone to making mistakes and this was my downfall when I thought I understood him and he comes back in a later video to clarify/correct himself. For instance, I've just started watching a video of his on testing a TPS and he's realised he needs to correct a principle test and instructs his class to amend his book books they purchased.

[darbuck]

Hi Mike can you put the link for that video up or pm me if you wish I am having a similar issue to Max wit a TPS IAC and knock sensor circuit as 3.3v but she still runs so maybe He can enlighten me to something I am missing

[MikeT]

Hi Mike can you put the link for that video up or pm me if you wish I am having a similar issue to Max wit a TPS IAC and knock sensor circuit as 3.3v but she still runs so maybe He can enlighten me to something I am missing

I didn't bookmark it but a search on his youtube account (scannerdanner) with relevant terms, should get a lot of helpful videos. First hit I get for instance


Would also be interested in the details of your 3.3v findings.

[ekjdm14]

Now this seems to be a potential development (both having a 3.3v ref. issue) that could at least help with diagnoses even if they do turn out as being dead ECUs.

It does however strike me as *potentially* more likely faulty ECUs though in that the reference voltage is the same to a tenth of a volt in both cases, but hopefully I'm wrong and it's just kind of a "default" protection mode when something gets shorted on that particular driver circuit. Will be very interested myself in hearing the outcome of these investigations, fingers crossed there's a common root cause and your ECUs can provide an answer for one another.

[darbuck]

I agree I have long suspected the ecu is kaput on mine it will be a simple check remove the ecu open it up and see if the driver has blown itself to pieces. but the problem is I have opened it before and all seemed OK no burning smell etc.so that is why I am checking. but at least with two of us looking for the same size voltage drop if one of us finds the cause it could lead us to a closer diagnoses. Just to know at this stage would be better than chasing our tails. Thanks Mike by the way.

[MikeT]

So if I got this right.... they designed a circuit to take measurements by pulling the positive to ground and it fails with error code, short to positive (or open) and expert opinion is the ECU's fried?

[MikeT]

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 %


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

Anyone know what "Temporary fault" indicates in this instance?

[darbuck]

Mike from looking at those readouts it looks like the sensor itself is no good

[ekjdm14]

So if I got this right.... they designed a circuit to take measurements by pulling the positive to ground and it fails with error code, short to positive (or open) and expert opinion is the ECU's fried?

Third-World-Skeptical-Kid.jpg

Not quite, as I see it the ref voltage should always remain at 5v and the ECU takes it's readings through resistive sensors that pass a percentage of said voltage to ground through the ECU's measuring medium. The only time the ref voltage itself ought to vary from 5v is if there's either a short in said circuit that loads the driver beyond it's capability to maintain this steady voltage (likely in the wiring prior to the sensor input IMO) or if there's a faulty component providing the voltage.

In this case I'm taking the fact that 2 separate ECUs have faults where a reference voltage has dropped to the same exact level within 0.1v to mean it's more likely than before that there's a common failure mode within the ECU's driver circuitry that causes this drop. That's not to say it isn't just a wiring fault, just that in my (inexpert!) opinion, the likelihood of faulty ECUs in both cases has gone up by a large percentage.

[MikeT]

Mike from looking at those readouts it looks like the sensor itself is no good

I believe max tested the sensor and even replaced it which is the fault code you see but as the circuit (without sensor) was also tested as no good, that's where we're at.

Not quite, as I see it the ref voltage should always remain at 5v and the ECU takes it's readings through resistive sensors that pass a percentage of said voltage to ground through the ECU's measuring medium. The only time the ref voltage itself ought to vary from 5v is if there's either a short in said circuit that loads the driver beyond it's capability to maintain this steady voltage (likely in the wiring prior to the sensor input IMO) or if there's a faulty component providing the voltage.

Yeah, I get that but it's so frustrating I sought humour being flippant. I should know by now it never translates well, should have kept it to myself.

In this case I'm taking the fact that 2 separate ECUs have faults where a reference voltage has dropped to the same exact level within 0.1v to mean it's more likely than before that there's a common failure mode within the ECU's driver circuitry that causes this drop. That's not to say it isn't just a wiring fault, just that in my (inexpert!) opinion, the likelihood of faulty ECUs in both cases has gone up by a large percentage.

Before Darren's input (excuse the pun ), I could find no other examples of a 3.3v signal input, in fact scannerdanner was the only place that came close, with reference voltages at either a lower 1.7v or 0v. Maybe my search methodolgy is lacking but that's all I found.
Also interestingly, many of the case studies scannerdanner uses are engine swaps (as with max's situation) with faults such as frayed rubbing or pulled looms, rotten earths and misconnected wires, faulty sensors as well as one case of reverse polarity when using a bluepoint professional charger - on booster mode - which made the battery explode! That DID fry the ECU.

Obviously, that's a way too small a sample to draw any meaninful conclusions from but scannerdanner has stated that symptoms of a failed 5v supply often equates to no comms with the diagnostic scanner too. i haven't found anything to confirm this though.

I think I made it clear way back when the ECU 5v pin measured 3.3v, I accept the ECU may well be at fault but since then we've got no closer to a definitive diagnosis leaving max facing even more expense he can ill-afford.