I have a problem with my Focus 2006 1.8 TDCI. It doesn't start and immobilizer light flashes code 16 which is communications fault between the PCM and the PATS system. Took the car to auto electrics and they found error in instrument cluster. I tried to repair it using this guide 

but it didn't help. Now I am out of ideas what can I do. Thinking to buy ECU kit on ebay and replace it. Before buying it I want to take all parts of my car to match part numbers. Just struggling to find location of ECU in my car. Any pics or guide about changing full ECU kit would be appreciated.

The ECM is under the front passenger wing, you need to take off the wheel and then the plastic cover. You will then find the ECM housing, a black box about the size of a a4 paper towards the front of the wing, the housing has tamper proof bolts, so you need to grind a slot into the bolt head to be able to unscrew them. Hope this helps.

On 1/7/2018 at 6:18 PM, Turtle Ninja said:

Thinking to buy ECU kit on ebay and replace it.

I assume that is an ECU & IC & locks & keys kit. They all have to be changed together, which is a big job with no guarantee, as the immobiliser codes are in both the ECU and the IC. So it is a bit of a last resort. And if there is a wiring or connector fault, it will not fix it.

So before that, I would check the connectors low down in front of the passenger door (3, I think, and the CAN bus goes through 2 of them.) There is also a big connector in the Engine bay fuse box that the CAN bus passes through.

Certain fuses (I think in the engine bay fuse box) can also do this if blown.

Error code 16 means the signals between IC & ECU via the HS-CAN bus, are not getting through.

There is a simple test that can be done on the HS-CAN bus:

There is no need to disconnect the battery. At least on my car the CAN bus went off about 30 sec after turning the ignition off. The PCM stays active for a while, I can hear it testing the EGR valve, and maybe doing other things, then it powers down and the bus goes dead.

Stick a couple of suitable probes (un-bent paper clips can work quite well) in the diagnostic connector pins 6-14, put a DMM across the pair on voltage range, turn ignition on, note reading, turn ignition off, wait till voltage drops to zero (+/- 1 or 2 mV), switch to resistance range to check for 60 ohms.

It should be stable at close to 60 ohms, any deviations would indicate a problem.

If 60 ohms, try tapping and moving various suspects, eg the fascia around the IC, the connector by the front door sill, the connector in the engine bay fuse box, and maybe the PCM. Look for any deviations. (IC = Instrument Cluster)

I did a little guide about repairing my IC, and that was the main connector on the back of the pcb, same as I think is shown in the video.

https://www.fordownersclub.com/applications/core/interface/file/attachment.php?id=40491