[Ian M Davis]

Nothing happens until I turn the key. Even turning the side lights on (as per the battery connection process) initialises nothing - only turning the key, and then once the key is turned, they don't shutdown until the battery is disconnected.

That fits with my suspicion that the ECU is unable to sleep. Perhaps it relates to the EGR.

Now that the car is cranking again do you know if there is synch between the crankshaft and camshaft sensors. If there is no synch the car will not start.

 

[sjuggins]

Now that the car is cranking again do you know if there is synch between the crankshaft and camshaft sensors. If there is no synch the car will not start.

There is still no sync between Cam & Crank.

I did just observe something funny... I was checking ABS for wheel/vehicle speed to see if it could detect it - it doesn't. However, after cranking for 2-3 seconds, when I let go of the key, my computer throws up the standard info/error telling you it's lost comms, check ignition is on etc... thing is, the ignition is still on and dash lights are on?

 

[sjuggins]

Bit more digging on the web to find more info on the reference 5v circuit as I suspect that could be an issue somewhere, and found the following relating to the EGR being a common issue with failures to start. I don't have any of these codes but talks about the 5v circuit also with other sensors:

EGR Valve Failure. Sometimes the engine does not start or it stops while on the move

In this post we are going to show you a common failure in many 1.6 HDi vehicles with engines developed by the French PSA group. Currently th...

carworkshopblog.blogspot.com

Is there any info/diagrams that specifically map out the 5v circuit from ECU?

 

[Ian M Davis]

There is still no sync between Cam & Crank.

I did just observe something funny... I was checking ABS for wheel/vehicle speed to see if it could detect it - it doesn't. However, after cranking for 2-3 seconds, when I let go of the key, my computer throws up the standard info/error telling you it's lost comms, check ignition is on etc... thing is, the ignition is still on and dash lights are on?

I wouldn't read too much into loss of comms with the diagnostic tool. That happened to me when I was using the Lexia 3 tool to program a new key. It happened twice. The first time didn't matter because nothing changed the second time was alarming because it had wiped the existing key before losing comms.

Bit more digging on the web to find more info on the reference 5v circuit as I suspect that could be an issue somewhere, and found the following relating to the EGR being a common issue with failures to start. I don't have any of these codes but talks about the 5v circuit also with other sensors:

EGR Valve Failure. Sometimes the engine does not start or it stops while on the move

In this post we are going to show you a common failure in many 1.6 HDi vehicles with engines developed by the French PSA group. Currently th...

carworkshopblog.blogspot.com

Is there any info/diagrams that specifically map out the 5v circuit from ECU?

I agree the crankshaft sensor signal and power is probably your main issue. I don't know of anything that maps the 5V supply in the ECU. I tried to list the units that would use it:
Camshaft sensor 1115 pin 1 wire 1352
Crankshaft sensor 1313 pin 1 wire 1312
ERG 1297 pin 1 wire 1310
Common rail fuel pressure sensor 1321 pin 3 wire 6772
Accelerator pedal 1261 pin 4 1380
MAP sensor 1312 pin 1 wire 1363

In the case of the crankshaft sensor your measurements suggest the functions of pin 1 and 3 are reversed to what the wiring diagrams show. The odd thing is the camshaft sensor voltages appear to be correct so there is not a common 5V rail failure.

EDIT
A couple of extra devices that probably use 5V. These are temperature sensors and you will only measure 5V at the plug with the sensor disconnected:
1240 Induction air temperature sensor pin 1 wire 1341
1310 Airflow meter (MAF) integrated temperature sensor pin 1 wire 1340

EDIT 2
One thing worth doing is unplug the crankshaft sensor and then do a diagnostic scan to see if it generates a crankshaft fault code.

 

[sjuggins]

The first time didn't matter because nothing changed the second time was alarming because it had wiped the existing key before losing comms.

Bet that was a tense moment!
I was interested in the loss of comms as the problem is consistentrepeatable, I can get it to lose comms every single time when scanning/interacting with the ABS module.

I agree the crankshaft sensor signal and power is probably your main issue. I don't know of anything that maps the 5V supply in the ECU. I tried to list the units that would use it:
Camshaft sensor 1115 pin 1 wire 1352
Crankshaft sensor 1313 pin 1 wire 1312
ERG 1297 pin 1 wire 1310
Common rail fuel pressure sensor 1321 pin 3 wire 6772
Accelerator pedal 1261 pin 4 1380
MAP sensor 1312 pin 1 wire 1363

In the case of the crankshaft sensor your measurements suggest the functions of pin 1 and 3 are reversed to what the wiring diagrams show. The odd thing is the camshaft sensor voltages appear to be correct so there is not a common 5V rail failure.

EDIT
A couple of extra devices that probably use 5V. These are temperature sensors and you will only measure 5V at the plug with the sensor disconnected:
1240 Induction air temperature sensor pin 1 wire 1341
1310 Airflow meter (MAF) integrated temperature sensor pin 1 wire 1340

Thank you very much for doing this, saved me a lot of work! Plan this weekend is to work through all those sensors testing for good ground, shorts etc.

My thoughts are the problems are a culmination of a bad ECU and the 5v supply’s or signal voltages being affected somehow, possibly by the ECU. I observed 3.44v on the EGR plug last night with it disconnected and the ignition on.

And of course, the chance the BSM is also faulty due to Pin 9 volt issue being observed.

EDIT 2
One thing worth doing is unplug the crankshaft sensor and then do a diagnostic scan to see if it generates a crankshaft fault code.

I never get a crank fault, plugged or unplugged. This also leads me to the ECU not operating correctly.

The replacement ECU will be here today/Monday. Am I at risk of damaging it if I plug it in and there’s any remaining wiring issues?

 

[Ian M Davis]

Bet that was a tense moment!
I was interested in the loss of comms as the problem is consistent repeatable, I can get it to lose comms every single time when scanning/interacting with the ABS module.

There are two sets of contacts in the ignition switch. One set is the ignition and the other is the starter. If you believe the ignition switch symbol in the wiring diagram the ignition ON set contact breaks contact when you turn to start.

My thoughts are the problems are a culmination of a bad ECU and the 5v supply’s or signal voltages being affected somehow, possibly by the ECU. I observed 3.44v on the EGR plug last night with it disconnected and the ignition on.

As far as I know Peugeot use 5V but some cars do use 3.3V so it may be the correct value.

I never get a crank fault, plugged or unplugged. This also leads me to the ECU not operating correctly.

The replacement ECU will be here today/Monday. Am I at risk of damaging it if I plug it in and there’s any remaining wiring issues?

The only reason for asking is you found the cambelt was slightly loose which suggests the tensioner has slipped which could mean the lack of synch is real.

The odd thing is the pin 1 and 3 designations on the crankshaft sensor appear to be opposite to the wiring diagrams.

I can't see any issue with trying the new ECU.

 

[sjuggins]

There are two sets of contacts in the ignition switch. One set is the ignition and the other is the starter. If you believe the ignition switch symbol in the wiring diagram the ignition ON set contact breaks contact when you turn to start.

Thanks for clarifying - interestingly I do not lose comms when live interacting with any other module, like reading the crank sensor live data or fuel. The loss of comms only occurs with the ABS module... perhaps it's nothing, perhaps it's another "possible" ECU fault. I'll park it for now.

As far as I know Peugeot use 5V but some cars do use 3.3V so it may be the correct value.

Interesting - OK I will keep investigating, I assumed it would be 5v in conjunction with others across the car plus the post I linked to earlier about common EGR reference 5v.

The only reason for asking is you found the cambelt was slightly loose which suggests the tensioner has slipped which could mean the lack of synch is real.

The odd thing is the pin 1 and 3 designations on the crankshaft sensor appear to be opposite to the wiring diagrams.

Hmm, what's also odd is that on none of the diagrams I've seen, there's no clear reference to the + & - pin designations, unlike the camshaft (1115) for example which clearly states pin 1 is positive & pin 3 is ground?

Could the appearance of the pins being swapped lie with an ECU fault? I'm not trying to blame the ECU for everything but considering it supplies all of those wires... unless there is a short to ground/positive on both the wires?

The cambelt being loose is still very real and needs addressing, I'm having a nightmare trying to get the wheel off and already snapped an extractor bolt. Somebody used an impact wrench on that locking nut as they stripped the security lugs. I'm going to be drilling out the whole nut... if not, it's an angle grinder and the whole wheel is toast.

I can't see any issue with trying the new ECU.

Great, thanks.

 

[RedSector]

The cambelt being loose is still very real and needs addressing, I'm having a nightmare trying to get the wheel off and already snapped an extractor bolt. Somebody used an impact wrench on that locking nut as they stripped the security lugs. I'm going to be drilling out the whole nut... if not, it's an angle grinder and the whole wheel is toast.

Take a few photos of the issue and see what I can suggest.

 

[Ian M Davis]

Thanks for clarifying - interestingly I do not lose comms when live interacting with any other module, like reading the crank sensor live data or fuel. The loss of comms only occurs with the ABS module... perhaps it's nothing, perhaps it's another "possible" ECU fault. I'll park it for now.

I suspect what happens is during cranking unnecessary modules are switched off.

Hmm, what's also odd is that on none of the diagrams I've seen, there's no clear reference to the + & - pin designations, unlike the camshaft (1115) for example which clearly states pin 1 is positive & pin 3 is ground?

The only reliable way with Peugeot SEDRE wiring diagrams to know the function functions of the pins is to look up the wire number up using the SEDRE tools. The wiring blocks shows what appears to be the pin function but more often than not wrong. The Haynes Pro procedure agrees with the SEDRE data but I suspect Haynes use SEDRE to write their procedures.

The cambelt being loose is still very real and needs addressing, I'm having a nightmare trying to get the wheel off and already snapped an extractor bolt. Somebody used an impact wrench on that locking nut as they stripped the security lugs. I'm going to be drilling out the whole nut... if not, it's an angle grinder and the whole wheel is toast.

The thing to remember about the Peugeot 308 and probably most other Peugeots is the wheels are held on by bolts. The last time I had to change a wheel it was really difficult because I had to take the weight of the wheel while trying to put the bolt in. I had to rest the wheel on my foot and use my foot to lift the wheel while I put the first bolt in. Wheel studs make changing a wheel so much easier.

The point about all this I think you should be able to drill down the centre of the problemsome bolt and weaken it enough to snap it off. Then you should be able to remove what's left of the bolt easily. You just need to buy a new bolt.

 

[sjuggins]

Here's a recap on today's troubleshooting which I hope is progress... 🤨

The first thing I found was related to 1310 MAF - I measured +12v on Pin 4 supply but when I pulled the corresponding fuse (F21) voltage dropped to 3.5v rather than disappear altogether. Thought this was odd but turns out it shares a common power feed via E300 connection which has another route to PSF1 and other sensors connected via that channel including 1261 (accelerator) & 1276 (fuel heater).

I couldn't really find any further issues with the 5v supply on the sensors so decided to double-check the resistance of all sensor wires back to ECU plugs - all good, nothing more than 0.5ohms anywhere.

The next thing I decided to do was check the earth wire resistance from the ECU side for every sensor, this is where it got interesting...

It transpires after a whole lot of testing that there appear to be some earth faults... not sure if my results are normal or not, I did Google but couldn't get any answers:

• Disconnect & reconnect battery - following proper procedure
• Nothing wakes as noted before - it needs the ignition to be cycled for ECU & relays etc. to wake
• Now then - if I test (back probe) the earth wires on any ECU connector back to battery ground I get 0.2-0.3 ohms across the board BEFORE cycling the ignition
• Cycle ignition On/Off - retest - every earth is 8-9ohms
• Cycle ignition and leave it On - every earth now reads 17-20ohms
• I tested further by taking 32v GR out and touching the meter probe directly to ECU pin = the same result
• Testing directly (back probe) from the main ECU earth connections (32V NR G4 & H4) = same result
• Testing directly from the wire connections for 32V NR G4 & H4 (plug disconnected from ECU) = 0.2-0.3 ohms
• Doing all the same sort of tests on a power side connection - all ohm readings less than 0.5 ohms
• All actual chassis and engine earths are fine

So, appears to me once the ECU kicks into life, the earth connections inside the actual ECU become faulty, could these be causing internal shorts to ground maybe... thoughts?

I observed the issues with Pin 5 & 9 power in a bit more detail:
Pin 5 & 9 have no voltage registering after reconnecting the battery, before cycling the ignition
Cycling the ignition On, Pin 5 shows 12v, Pin 9 0v
Cycling the ignition Off, Pin 5 continues to show 12v, Pin 9 0v

Finally, using my power probe I tested all fuses and connections across the BSM/Fuse box - observing which fuses were powered with the ignition on, and which weren't.
Several fuses including F9 and F13 aren't live with the ignition on, however, if I applied power (briefly for less than a second) directly to F9 relays clicked and then headlights and wipers started working? Cycling ignition on/off stopped everything. Not sure if any of this is relevant.

The wheel bolt I will leave for another day...

 

[Ian M Davis]

That is a good summary.

The area I want to go over is your resistance measurements. You should never do resistance measurements with the battery connected. This is because a tiny voltage drop caused by a correspondingly tiny resistance can cause the Ohmmeter to read a false high resistance. That is why you are seeing the resistance reading change when you turn the ignition on.

My prefered way of checking earths is to measure the voltage drop with as much equipment turned on as possible. If your earth point is passing 30A a 0.1 Ohms resistance means you will get a 3V drop. You can easily measure 3V but measuring 0.1 Ohms is very difficult.

If the 0.2-0.3 Ohm resistance value in the ECU earth is real it would cause a lot of problems so it is worth checking voltage drop across the two measurement points with the ignition ON.

Notes
1. The Haynes Pro procedures usually set the upper resistance at 0.5 Ohms. That is okay for checking continuity of signal lines but not for anything that carries much more than 100 milliAmp.

2. The top of the range Fluke multimeters have a resistance resolution of 0.1 Ohms and an accuracy of 0.9% +2. What Fluke are telling you is you not only need to add and subtract 0.9% to the value you must also look at the resolution. In the case of the Ohms range the resolution is only 0.1 Ohms so you have to add +/-0.2 to the reading as well as the percentage. For example if you you measure 0.5 Ohms the actual value is between 0.2955 to 0.7045 Ohms. Fluke are being very honest, multimeters can't accurately read very low resistance.

 

[sjuggins]

That is a good summary.

The area I want to go over is your resistance measurements. You should never do resistance measurements with the battery connected. This is because a tiny voltage drop caused by a correspondingly tiny resistance can cause the Ohmmeter to read a false high resistance. That is why you are seeing the resistance reading change when you turn the ignition on.

My prefered way of checking earths is to measure the voltage drop with as much equipment turned on as possible. If your earth point is passing 30A a 0.1 Ohms resistance means you will get a 3V drop. You can easily measure 3V but measuring 0.1 Ohms is very difficult.

If the 0.2-0.3 Ohm resistance value in the ECU earth is real it would cause a lot of problems so it is worth checking voltage drop across the two measurement points with the ignition ON.

Thanks Ian for explaining in detail a better process. Still learning (clearly)… good job this is a £200 car and not a £2k+ car 🤣🤣

Given that I can’t load the circuits very much as I can’t start the engine and it’s in economy mode, how would you suggest I modify my approach?

I’ve got access to the Haynes Pro now (thanks Red) so will be reviewing the tests in there in more detail.

Really thought I was on to something with those earth results.

 

[Ian M Davis]

Given that I can’t load the circuits very much as I can’t start the engine and it’s in economy mode, how would you suggest I modify my approach?

Just turn the side lights and ignition on.

Really thought I was on to something with those earth results.
[/QUOTE
That very problem had me puzzled for a couple on days on another discussion. Multimeters only use a few millivolts on the Ohms scale so a tiny voltage will cause them to read a very high resistance. Just try measuring a resistor using two multimeters at the same time both meters will read a value much higher than the actual resistance.

 

[sjuggins]

Some more testing today...

For the first time since we got the car, I connected the fully charged battery this morning (same as every test session) but this time the Radio/Windows, etc. all spang to life (no economy mode)... lasted about 10 minutes but confirms it's a power issue and not grounds etc. with those which is good.

The first thing I found was related to 1310 MAF - I measured +12v on Pin 4 supply but when I pulled the corresponding fuse (F21) voltage dropped to 3.5v rather than disappear altogether. Thought this was odd but turns out it shares a common power feed via E300 connection which has another route to PSF1 and other sensors connected via that channel including 1261 (accelerator) & 1276 (fuel heater).

Did some further testing on the MAF from yesterday to diagnose once and for all - tests all indicate fault lies with ECU:
Getting 0v on Pin 1 & A G2 - resistance measures 0.2 ohms. Haynes Pro confirms fault is likely ECU.
Should be getting 12+v on Pin 4 but I'm getting 11.3v whereas, at the BSM Pin C2, I'm getting 12+v, again if I pull F21 it drops to 3.5v and so does Pin 4 on the MAF. Resistance on this wire was 0.5 ohms.

Revisited the Accelerator tests to try and diagnose DTC P0122 now we know the pins are correct.
Passed all tests with the exception of the tests between Pin 4 and B G2. Measured 5v at the sensor and ECU when it should be <0.2v. Resistance/continuity came up as OL - checked with the connector in place at the sensor and unplugged, made no difference. According to Haynes Pro, the fault lies with ECU again.

Finally, went back over all the earth testing from yesterday but used a modified test process (thanks Ian). I actually used a test lamp to check for dim connections but all were consistently same brightness with ignition and side lights on... I got this test from here (bottom of Fault 8):

Storingzoeken in sensorbedrading - MVWautotechniek.nl

Onderwerpen:InleidingMeting zonder storingStoring 1 - Onderbroken signaaldraadStoring 2 - Onderbroken voedingsdraadStoring 3 - Onderbroken massadraadStoring 4 - OvergangsweerstandStoring 5 - Kortsluiting tussen voedings- en signaaldraadStoring 6 - Kortsluiting tussen voedings- en...

www.mvwautotechniek.nl

I also followed the Haynes Pro full tests for ECU connectivity which start with ground tests, I noticed it mentions doing a resistance check with MC10 like I did yesterday, noting it should be less than 1ohm:

Replacement ECU should be here tomorrow 🤞🤞🤞

 

[Ian M Davis]

Did some further testing on the MAF from yesterday to diagnose once and for all - tests all indicate fault lies with ECU:
Getting 0v on Pin 1 & A G2 - resistance measures 0.2 ohms. Haynes Pro confirms fault is likely ECU.
Should be getting 12+v on Pin 4 but I'm getting 11.3v whereas, at the BSM Pin C2, I'm getting 12+v, again if I pull F21 it drops to 3.5v and so does Pin 4 on the MAF. Resistance on this wire was 0.5 ohms.

Should be getting 12+v on Pin 4 but I'm getting 11.3v whereas, at the BSM Pin C2, I'm getting 12+v, Something is wrong here. Pin 4 of the MAF is a main power line you should not be getting a voltage drop like that. The battery voltage should be about 12.7V. If you are only measuring 11.3V at the MAF it means you are getting a voltage drop across the wire (0003) of 1.4V. If your resistance measurement of 0.2 Ohms is correct the MAF is drawing 7A and the wire is dispiating 9.8W. If that case the wire will be getting very hot. I think you have a bad connection on that wire.

In reality no power wire should have a resistance as high as 0.2 Ohms. A solid copper wire of 1 mm diameter and of 3m length has a theoretical resistance of 0.067 Ohms.

I have attached an alternative wiring diagram which shows the spices and wire 0003 has a splice E300. I will see if I can find some location data.

 

[Ian M Davis]

I have attached some more details on wire 0003. There is a harness interconnection (3V NR) in the engine compartment. This will be a plug and socket. I have attached the location diagram. I suggest you find it and check it. I suspects there is a bad contact there.

EDIT
The same plug and socket also connects:
Pin 1 Diesel fuel heater (1276) to engine fuse box (BSM)
Pin 2 MAF to E300 (splice in wire 0003)
Pin 3 Engine ECU (1320) to accelerator pedal position sensor (1261)

 

[CJX]

Ian M Davis said
"... If your resistance measurement of 0.2 Ohms is correct the MAF is drawing 7A and the wire is dispiating 9.8W..."

Given this, & the OP's reference to "parasitic" current drain - introduced @ #46 on p3
Is there merit in using a "DC current" capable claw or clamp meter (borrow/hire/buy) to probe the battery to earth lead, & progressively pull & replace fuses, to isolate ?
Ian M Davis/Red Sector might suggest a more targeted use of the tool, given what's been investigated so far

And, from left field:-
Is the Parc/k Shunt link in the correct position ? (as this would prevent the engine firing AFAIK)

 

[Ian M Davis]

Ian M Davis said
And, from left field:-
Is the Parc/k Shunt link in the correct position ? (as this would prevent the engine firing AFAIK)

I think you will find that when the shunt is in the park position it only disables a few things such as the radio when the ignition is OFF. What is meant to happen is when the car leaves the factory the shunt is in the Park position and the dealer changes it to the Customer position.

I have attached a wiring diagram for the BSI. You will see that the shunt changes the connection to fuses 8 amd 10 from being directly connected to the battery to a connection controlled by the ignition switch. The devices involved are:
F8
Tyre under inflation detector, multifunction display,radio telephone, audio system, trailer refrigeration supply relay and interior storage lock
F10
Steering Wheel controls, anti-theft alarm, anti-theft alarm siren

 

[sjuggins]

Should be getting 12+v on Pin 4 but I'm getting 11.3v whereas, at the BSM Pin C2, I'm getting 12+v, Something is wrong here. Pin 4 of the MAF is a main power line you should not be getting a voltage drop like that. The battery voltage should be about 12.7V. If you are only measuring 11.3V at the MAF it means you are getting a voltage drop across the wire (0003) of 1.4V.

By the time I came to this test, the battery was down to around 12.3v - I've charged it again and will reconnect and restest to see the actual voltage drop... that being said, tests from last night would be around 1v drop which is not good either.

I have attached some more details on wire 0003. There is a harness interconnection (3V NR) in the engine compartment. This will be a plug and socket. I have attached the location diagram. I suggest you find it and check it. I suspects there is a bad contact there.

EDIT
The same plug and socket also connects:
Pin 1 Diesel fuel heater (1276) to engine fuse box (BSM)
Pin 2 MAF to E300 (splice in wire 0003)
Pin 3 Engine ECU (1320) to accelerator pedal position sensor (1261)

Thanks, Ian for the continued support and investigation 👍

I did come across the E300 connection myself (see post #90) as I observed there is always 3.5v after pulling F21. I did disconnect/reconnect the 3V NR connector for E300 previously but I will inspect it again in more detail. Haynes Pro does recommend replacing wires if >1ohm, I will test this again with BSM plugs disconnected. I could not find the splice however for E300 - I'll inspect this too now I know it's in the passenger footwell.

I've not come across many tests where I get 0.0ohms resistance across wires, perhaps it's the probes I'm using skewing results upwards?

Will report back later.

 

[sjuggins]

I think you will find that when the shunt is in the park position it only disables a few things such as the radio when the ignition is OFF. What is meant to happen is when the car leaves the factory the shunt is in the Park position and the dealer changes it to the Customer position.

I have attached a wiring diagram for the BSI. You will see that the shunt changes the connection to fuses 8 amd 10 from being directly connected to the battery to a connection controlled by the ignition switch. The devices involved are:
F8
Tyre under inflation detector, multifunction display,radio telephone, audio system, trailer refrigeration supply relay and interior storage lock
F10
Steering Wheel controls, anti-theft alarm, anti-theft alarm siren

I'm not really sure what you and CJX are referring to in this post... remember my car is manual not auto - if you mean 'Park' as in the auto gear selection

If however, you mean 'park' as a configuration in the BSI to set certain parameters/components to a pre-set level before customer acceptance... I did wonder if considering the BSM and ECU has been replaced, has the BSI and left in some 'non-correct' configured state?

The car was running fine remember after the ECU/BSM replacement, it just stopped one day... apparently!