This could be a long story so I apologise in advance to anyone who may get bored easily.
My story. I bought the car just a few months ago, 2008 1.8TDCI with 82k on the clock.
It's my first Focus and I was well pleased with it till about 4 weeks ago while driving around town, the Engine Malfunction warning appeared between my clocks.
The car still drove normally, no limited revs no EML.
It's been a very long time since I last tinkered with any cars and when I did, they didn't have "brains"
After reading a lot of stories both here and other sites, I bought myself a modified ELM237 USB dongle and armed with Forscan loaded on my laptop read the DTC's stored on the car.
I was pretty shocked at the number of errors I found, but I cleared them and scanned again many times, each time producing various errors, but almost never the same ammount or type of errors.
P0087 - Fuel Rail/System Pressure - Too Low
P0299 - Turbocharger/Supercharger Underboost
C1956 - Steering Angle Sensor Circuit Failure
U1900 - Missing Message for Engine Speed
U1900 - CAN communication bus fault
B2894 - Decklid Release Circuit Failure
P1639 - PCM Vehicle Identification Block Corrupted or Not Programmed
All these had shown up multiple times. Sometimes when cleared the car would start normally, sometimes it would crank much longer than normal before starting, and sometimes it just refused to start.
I spoke to a friend in the trade who came and had a look. He checked a few things and finally suggested I have my cluster tested. I arranged with a company to have the cluster checked and if found faulty, repaired. I had a call after they tested it and confirmed it faulty. I gave them the go ahead to repair, and it was returned to me 2 days later.
I refitted the cluster, switched on the ignition and was presented with the "Engine Malfunction" alert again.
I hooked up the laptop and read the DTC's again.
Intermittent error codes since fitting the rebuilt cluster include:
Code: P1639 - PCM Vehicle Identification Block Corrupted or Not Programmed (most common).
Code: U1900 - CAN communication bus fault.
Code: C1956 - Steering Angle Sensor Circuit Failure.
Code: U1900 - Missing Message for Engine Speed.
That was last week. I called the company that repaired the cluster and they offered to test my ECU.
I packaged up the ECU, cluster and key and sent them off.
They messaged me yesterday and informed me that the ECU passed all tests and both that and the cluster have a clean bill of health.
They shipped my items back to me and I took delivery of them this morning.
Today I fitted the ECU and cluster back into the car, switched on the ignition and there was the "engine Malfunction" message again.
I cleared the DTC's again and the car started instantly. I let it warm up sitting in the drive way then took it for a 15 minute drive. No errors were recorded during this time.
Once back in the drive, I switched the engine off and restarted it. The warning was back again as soon as ignition was on, but the car started fine.
I repeated the process a few times, and each time the same result. Reading the DTC's gave only 1 code every time.
Code: P1639 - PCM Vehicle Identification Block Corrupted or Not Programmed.
Over the next hour or so I repeated the process of starting and switching off the engine and I think every time had the same result as above.
I cleared the code, started the car and took it for another drive. This time I drove for over an hour. No warnings and car drove fine.
I came back home and switched it off. Turned ignition back on and the error P1639 was there again.
If i clear the code and start the car, there are no warnings till the ignition is switched off and on again.
As the ecu has tested fine, I'm at a loss what to do next.
If any one out there has managed to stay awake through all this, I would welcome any input offered as I'm all out of ideas.
Many thanks for getting this far :)