Immobiliser fault help!!!

[ans8907]

Hi all, 

 Am really desperate for some advice or help if anyone has come across this issue with their fiesta. In April it broke down for the first time while I was driving at low speed. When I tried to re start the engine the immobiliser light flashed and it wouldn't start. Nothing shows on diagnostics when it is in this state and disconnecting the battery makes no difference. It will then start again after around 8-12 hours although sometimes less. This has happened 12 times now in the past four months and all the garages I have taken it to don't seem to have any answers. It has stopped when I've been driving fast, slow, idling or sometimes just won't start after being parked. Usually at least a few days between breakdowns- sometimes even two weeks. The immobiliser fault code that is flashing up is code 16 which is a communication fault. Last week when it was broken down the garage it was taken to (a local dealership that sells ford) thought they had got somewhere as it came back to life when they fiddled with the ABS connection. All connections have been checked and grease applied but it has still broken down again. Thinking about replacing the transponder as next step but wondered if anyone had this problem and could shed some light please?? Very grateful for any replies at all!!

Thanks

[Tdci-Peter]

8 hours ago, ans8907 said:

The immobiliser fault code that is flashing up is code 16 which is a communication fault.

It certainly is. It is a fault on the car's main CAN bus that links all the main modules together. When diagnostics are run, there may be apparent errors in many modules. The ABS appears often, but is unlikely to be the cause.

With code 16, it is less likely to be the PATS transponder.

On the Focus, I would say it is 90% certain to be the IC (Instrument cluster). The Fiesta is not so different, and I would put that unit at the top of the list.

This unit is very expensive to replace, but can be sent away for test & repair for under £100, usually.

When you say: Nothing shows on diagnostics, what system were you using? A basic OBD2 system is very limited outside of engine faults.

For this sort of fault, Forscan is by far the best option.

Peter.

[ans8907]

Thanks very much for your reply.

 

Do you think I should request that they send off the instrument cluster for testing? At the moment they are saying that they want to do tests ford have suggested but can't do them until it is in the broken down state and we don't know how long it will be before that happens!

 

I don't actually know what diagnostic system they have been using but I will certainly ask. I had hoped that by taking it to the dealership which sells ford that they would have the best and most in depth scanning equipment, compared to the smaller independent garages I've been taking it to up until this point.

[Tdci-Peter]

2 hours ago, ans8907 said:

I had hoped that by taking it to the dealership which sells ford that they would have the best and most in depth scanning equipment,

A ford dealer should have the Ford IDS system, which is (or should be) better than any system like Forscan, available for DIY diagnostics. Some independent garages may have this, but it is expensive, so not all will.

As for waiting for the fault to re-occur, I think I would be inclined to do the same. With only the flash code 16 to go on, there is some risk it is not the IC, and additional risk that testing the IC may not reveal an infrequent intermittent fault. Perhaps if I was going to be using the car on a lot of long or critical journeys, I would have the IC tested as a precaution, but otherwise I would wait, just making sure my breakdown cover was up to date & I had a phone!

Error codes (DTCs) stored in the car seem to vary in how long they last. Some vanish after a few drive cycles, so have to be detected as soon as they occur, some seem to linger for weeks. That is why getting diagnostic information promptly is important, and is one reason that I recommend DIY diagnostics. Most Ford dealers do not like this, for various reasons, some good, some just greedy. They do not like owners, or internet forums, "interfering" with their job!

 

 

[ans8907]

The thing is I've been just driving it anyway and trying to get it to them in a broken down state for months!! I have had 12 breakdowns in 4 months and to get the planets to align so it happens when they are open and have time to look at it is nigh on impossible! (It resets itself and works again after 8 hours so if left overnight it's pointless). I've only managed it once and that was week before last when they thought they had solved it by checking the connections between the ABS and CPU. The diagnostics didn't show anything then even when it was down. It then still broke down again after they'd sorted all connections and greased everything up. I really feel like something concrete needs to be done now as we are getting nowhere by just waiting and watching- it's been to long now! I'm self employed and I need my car for my job. At my wits end :( thanks for replying again. I really am very grateful!!!!

[Tdci-Peter]

4 hours ago, ans8907 said:

it's been to long now! I'm self employed and I need my car for my job

If it is any consolation (and I am almost sure it won't be!), you are not alone if this sort of electrical/electronic problem that defeats garages & drags on for weeks or months. Not just the Fiesta, and I am sure it is not just Fords, it is that garages really struggle to keep up with the complex electronic systems on modern cars.

In most Fords, two electronic modules are primarily involved the the PATS (immobiliser) system. They are the pcm (engine computer), and the IC (Instrument Cluster). A pair of wires, called the HS-CAN bus, links these two modules. Various other modules, including the ABS, are connected to branches off this bus. The PATS sensor, which is around the ignition key barrel, is connected to the pcm. The pcm controls all engine functions, and will not operate unless the PATS system says it should. But it must communicate with the IC in order to obtain the needed codes. This system provides a high level of security, it can not be simply by-passed. But it is a pain when it goes wrong.

With flash code 16 indicating a communications error, I suspect the link between these two modules. If this link malfunctions, many errors can result, including ABS errors. But prime suspects are the wiring itself, the IC and the pcm.

The HS-CAN  bus wiring has several joints or "splices", and one or two connectors. So there may be a failure there.

The pcm and the IC both have 120ohm terminating resistors across the bus, and a simple resistance test, looking for 60ohms from one line of the bus to the other, can test the integrity of the bus wiring. This is part of the normal Ford test procedures. Any good garage, or auto-electrician should be able to do this test, or a competent diy'er with a multimeter. Tapping the fascia around the IC, and disturbing the connectors may help reveal a fault. (The bus is accessible on pins 6 & 14 of the diagnostic connector). If this test revealed a failure, it could quickly be pinned down to either the pcm end or the IC end of the bus.

Having a Forscan system to hand in the car might help solve the problem of getting it to the garage when "broken". It does produce a log file of the errors. It runs best on a laptop, but phone/tablet (iOS or Android) versions are available. The cost is £15 for the laptop (just for the adapter), a bit more for the wireless versions. It is easy to use once set up, but may need a certain amount of computer literacy/knowledge to install & get working.

The alternatives seem to be to force the garage to undertake extended testing, which may be expensive, or replace the car!

My initial diagnosis was, as I said, based on the Focus, where the PATS sensor is connected to the IC, and there is a known history of failure. The Fiesta is a bit different, the sensor may be connected to the pcm, but all indications are that the IC is still strongly involved, & remains a suspect. It is hard to reach a firm conclusion with only flash code 16 as evidence.

 

In case you are interested in the Forscan route, some details follow:

It is a powerful Ford specific system. Cost £15.00 for the interface. Needs a computer of some sort. (COM port, USB, bluetooth or WiFi interfaces available). Not as simple as the self contained OBD2 scanner. You will find a lot about ELM327 & Forscan on this site, which together provide a very comprehensive diagnosis & maintenance tool. Post here if you want more info. James (jeebowhite) has done a nice guide: http://www.fordownersclub.com/forums/applications/core/interface/file/attachment.php?id=21196 is a

For an ELM327 adapter, see
http://www.spanglefish.com/TunnelratElectronics/index.asp?pageid=516992

The Forscan programme is free and you can get it from:

http://forscan.org/download.html

 

[ans8907]

Thanks again for your reply. As an update- I've picked the car up from the garage in the hopes I can get it to them next time it's broken down for them to test the resistance of the connections when it is in the broken down state and possibly isolate the problem. This is what ford recommend they do. I'm also looking into getting a second hand instrument cluster for them to programme and fit as a cheap way of ruling that out as the cause of the issues. The best we can do for the moment I think! 

[Kaloyan]

Does anyone know where the location of the immobiliser is on a Ford Fiesta 2009 1.4 petrol 

[Stoney871]

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