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ECU/PCM ?


Right Foot
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Ford Focus 1.6tdci 2005  (challenged)

Long story short, no power to glow plugs, break found in small wire going to heater plug relay, wire was repaired, now engine turns over but doesnt start and engine management light on.

Repaired small wire traced to ECU

Is the fault of the engine not starting down to a faulty ECU

On ebay we have found identical ECU units with matching part numbers etc, would this be a straight swap?

Any advise appreciated.

Edited by Right Foot
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1 hour ago, Right Foot said:

now engine turns over but doesnt start and engine management light on.

Before buying a new ECU, you should find out the diagnostic code(s) related to the EML being on. Most OBD2 scanners will read most engine codes.

Changing the ECU is definitely not simple plug and play. There are settings like injector calibration codes stored in it, and the immobiliser key codes. It will need quite a bit of re-programming to get a replacement ECU to work.

It could be something relatively simple like air in the fuel supply. These engines will need priming to pump fuel into the diesel pump if air gets in to the system.

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Ok thanks how do I reprogramme an ECU?  Even if it is identical in numbers etc

Is this a garage job?  or if the part numbers match exactly will it relearn codes from turning key on and leaving for a set amount of time?  I am so confused by all this.

If this is a garage job, then it truly isnt worth the expense.

Any input greatly appreciated.

 

 

 

 

 

 

 

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After changing the PCM it will be necessary to reprogram the new PCM completely.

The PATS immobilzer system needs to be reprogrammed. The PCM is part of the PATS system. When changing it the PATS system needs to be reprogrammed otherwise the car will never start.

The PCM software also needs to be reprogrammed. Incorrect PCM software can cause several problems. In worst case even engine damage. Even if the PCM hardware number is identical the PCM may have a different software version. Because of this it is very important to make 100% sure the new PCM has the correct software version.

The PCM also contains a configuration. When changing the PCM the configuration needs to be changed to match all settings/options of the car. This file contains data like VIN number, vehilce type, body type, transmission type, alternator capacity, tire size, gear ratio, with/without Cruise Control, fuel quality, etcetera. If not configured correctly some functions will not work correctly or will not work at all.

 

If you do not have the knowledge or tools to succesfully reprogram a PCM I suggest you to take it to a Ford dealer. 

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3 hours ago, Right Foot said:

frightened there may be a few, will update this thread with his findings! 

DTCs are not something to be frightened of! It is the fault itself that can be frightening, or the cost of fixing anyway. The DTCs are there to help locate the fault. They are knowledge, and knowledge is power! At least sometimes. unsure.png

Unfortunately, neither the car's systems, nor the people who designed & programmed them, are perfect. The DTCs try to be helpful, but are not always 100% correct. But they still do help.

Another simple reason for a diesel to fail to start is the engine not cranking fast enough. It needs a certain speed (my 1.8 needs about 200rpm) before it will try to fire up. If the battery is a bit tired, that could be enough, even if the engine still seems to turn over ok.

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aye, correct me if I'm wrong but I didn't think the glowplugs are integral to combustion in warmer climates, the compression of the fuel air mix generates the heat required to set it off,  the glow plugs are more of a boost when its cold then anything else, they do not behave like spark plugs in a petrol.

whats needed is the correct amount of Air, fuel and compression all at the correct time. without one of those you are not going anywhere

The DTCs will be a big help in flagging where the problems are coming from but a damaged PCM will muddy the waters a lot, I would suggest you note down all the DTCs, then reset them, turn it over a few times then check again, you may have DTCs that have been on there for ages, theres no point in muddying the water even more so clear them and try again.

if this guy whos coming to check your codes is charging you more than £20 you should tell them to forget it and buy the gear yourself

http://www.spanglefish.com/TunnelratElectronics/

comes highly recommended for the hardware and the software, Forscan, is free.

 

 

 

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On modern Diesel engines the glow plugs are not only used for starting. In fact most modern common rail Diesel engines do not even need the glow plugs to start properly.

When the engine is running the glow plugs are also used to reduce emissions during startup and warmup of the engine. Until the engine reaches its normal operating temperature the glow plugs are still active. Depending on the outside temperature this can take a pretty long time.

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3 hours ago, Right Foot said:

no dtc registered, not getting reading from ECU!!!!

If that means that the diagnostic reader could not access the ECU, then that would probably prevent the car from starting. Likely causes of this are:

Bad connection or broken wire in the CAN bus wires between the diagnostic connector and the ECU. As the Instrument Cluster (IC) also uses these same wires to talk to the ECU, this would prevent the car from working.

Lack of power to the ECU: Check fuses F33, F34, F35, F36, F28 & F9 in the engine bay fusebox.

Faulty ECU.

Faulty IC. I put this down because it is a common fault on 2006 Foci, and maybe some 2005 ones. But your symptoms do not sound like the usual faulty IC ones.

Note: a faulty crank sensor will often give a DTC, but it will not prevent getting readings from the ECU.

Darren (Dee_82) recommended Forscan as a good diagnostic system, and I very much agree. It will talk to all the modules in the car that it can find, and list them, and display a wider range of problems than probably any other system apart from the Ford IDS system found at main dealers. And it only costs about £16 for the adapter. If the EML ( engine management light) is on, there will be a DTC stored somewhere.

 

 

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Thanks for your reply, we have ordered Crank Sensor (as this is relatively cheap to try, at least!), husband will check out canbus wiring as much as he possibly can, we will speak o guy with diagnostic tool, as he did say if replacement of Crank Sensor didnt work he would come back and have another look, and we will mention to him about Forscan at the same time, not sure what diagnostics system he was using.

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"No Coms with ECU .....so lets change the crank sensor". 

To be honest, I'm Not sure I follow your train of thought there!

If  your getting no coms with the ECU at all then its time for one of two things, firstly, as Peter said above, check all plugs and fuses, especially the plugs on the ECU and GEM, as well as the engine fuse board and where possible check the wiring looms for broken wires, especially between the OBD port and ECU, some of these will be too hard to visually follow so use a DMM to test continuity end to end and also check if there is any continuity between live and data wires as well as earth. failing that or if you are unable to check them, its time to take it to a specialist because there is no means for you to test the ECU itself.  The fact the ECU isn't saying "hello" is a big problem trying anything else at this point will be fishing for a problem, doing it this way you could replace most of your modules and wiring looms in your car before you find the problem. 

have you tried taking off the battery for 15-30 min,? 

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  • 2 weeks later...

Update all, wires all checked and nothing found to be a problem.

Not sure if still will have powertrain light come on once it is driving, but it turns out the injectors are not working as they should, managed to get car started, runs perfect, however powertrain light flashes if you rev it up to around 2000 rpm!  thinking it now has a fuel starvation problem!  We are getting the injectors checked and tested tonight to check the pressures and the leak offs, will update you all.

Bought another ECU to no avail, just creates more headaches reprogramming keys etc, but turns out it isnt the problem after all!

Fingers crossed it will be an injector and then it can be replaced and we are good to go again as they say.

Thankfully I havent had to use a garage for all of this as it would be too costly.

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dude, you need an ELM 327 device and find out exactly what the ECU is saying,  i know you had someone out to check them but for some reason couldn't get it to talk but if you are able to start the car albeit, sub 2000RPM, then you should be getting some coms with the ECU.  if you have fuel starvation issues it will flag as a fuel starvation problem.  I know its tempting to just start replacing stuff but until you narrow it down you could end up replacing half the car before you get it right, if you go to a garage and ask them to check and change the injectors, they will probably find a problem with them and release you of a few hundred pounds to replace them, you don't want to be paying for their fishing which you will do if you have told them to do something.  if your not happy to fault find this yourself then just leave it to them, they will probably get a diesel specialist in to take a look  

Ive had erroneous fuel sensor readings and starvation issues and ive yet to see a powertrain malfunction light up. it usually starts with hesitation under load and random cut outs, it will have a whole bunch of DTCs flagging pressure warnings.

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  • 2 weeks later...

Injectors were all fine, ECU was returned as not needed and wasn't the problem.

It turn out to be fuel starvation as the Fuel Pump Pressure Regulator Control Valve wasn't working, purchased new unit from ebay and fitted and all good to go.

Hopefully all will now be well, and thank you for all for your suggestions/advice.

 

 

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  • 2 years later...

have a 2010 Focus TDCi back in November I had a new EGR valve fitted everything was fine after a routine service I was told I needed a new turbo and cambelt this was replaced but after getting it back back the engine management light came back on on so decided to take it back to the garage but on the way there the light went out. the garage said it was the EGR valve again they realised the EGR valve shouldn't have gone so thought it was a problem with my ECU they sent this off to be checked it came back with no fault the engine management light went off so they gave the car back to me after having the car back for one day the engine management light is back on any help or advice would be much appreciated

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the EML (orange engine management light) is a simple warning to inform the user the car has detected something in the way the car is running is not right.  It can be big things or little things that activate the light.  In general its trying to say continued use with this failure mode is not to a good idea.  It might mean engine damage will occur, or just that its using too much fuel and emissions are incorrect with little harm... or that a CAT or DPF etc. with be damaged, or all of them.

So always best not to continue to drive with this illuminated until someone has plugged in decent diagnostic equipment and understands the fault.  Some are insignificant and can be ignored, others not.  The light doesn't state how bad the fault is.

As you've been to a garage, one hopes they have the equipment and knowledge to fix it.  However as car's get more sophisticated especially on engine management (how they run) and emission control, many old school garages have no idea what they are doing and tend to throw a few parts at the car and hope.  This can be very costly and fixes nothing.  This is where main dealer spec diagnostics and experience comes in.

There will be fault codes stored in the vehicles ECU or live data from various sensors that explains exactly what is causing the light to come on. It might be simple, might be set up, might be a senor has failed or a component has worn out.  But this garage seem clueless / out of their depth, so not a great idea to go back to them... although many would suggest you do.

Depending on vehicle age and mileage multiple small faults can land on top of one another and garages can get the blame for the fact its old....  everything is designed to die these days, but a garage with the right experience and tools will easily know exactly what to do....

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