I have had a 2010 Fiesta 1.4 diesel for 2 years. It has just over 100k on the clock. Three days after its MoT (passed OK) all the wipers stopped working. Then the front electric windows stopped working. Next the brake lights stopped working, then the central locking stopped working.  The car has spent a month in a garage where they eventually fitted a newish BCU. That made no difference and they said it must be the wiring. Driving back from the garage the central display kept saying "engine malfunction" and "engine service now".  I have the car at home now. Now the central locking has failed. An odd thing is that an alarm sounds and the central screen says "engine malfunction" and "engine service now", which I would expect if the ECU was also faulty. I would be grateful for any thoughts on this problem. I'm well into "the sticks" with no main agents etc anywhere near.  The irritating thing is that the car is fine in itself. If the BCU was failing why is the engine warning coming on. Surely that is the ECU? Any suggestions, ideas , commiserations gratefully accepted.

56 minutes ago, aetheric said:

If the BCU was failing why is the engine warning coming on. Surely that is the ECU? Any suggestions, ideas , commiserations gratefully accepted.

Seems a bit of confusion here.

The BCU is actually called the Body Control Module (BCM). The ECU is called the Powertrain Control Module (PCM).

On older model Fords the BCM was actually the General Electronic Module (GEM) which maybe what your car has, but regardless as to whether you have a BCM or a GEM the faults you have with the vehicle electrics are almost certainly the result of a faulty BCM/GEM

Second hand replacement units have to be the exact same part number. The very last letter of the code can be different, so long as it is higher. For example a unit ending 'B' could be replaced with a unit ending 'C' or 'D' or 'E' but not with a unit ending 'A'

Once the replacement is fitted it will need to be reprogrammed with your vehicles "AsBuilt" data or it will not function correctly.

The BCM has now been replaced (correct part number etc) and successfully cloned from the original with FORscan. Sadly the problems persist. Below are some faults I managed to get from the car using FORscan. Beyond tracing all the looms and looking for a fault I'm open to any suggestions as to what else to check for:

===FCDIM DTC None===
Successful DTC reading, no error codes found

Module: Front Control/Display Interface Module

===END FCDIM DTC None===

===ACM DTC U3000:49-2F===
Code: U3000 - Control Module

Additional Fault Symptom (:49):
 - Internal Electronic Failure

Status (-2F):
 - DTC Present at Time of Request
 - Malfunction Indicator Lamp is Off for this DTC

Module: Audio Control Module

 Freeze Frame  #1:
-EVENT_TIME: 22371136 s - Event time
-TOTAL_DISTANCE: 163649 km - Total Distance
-MODULE_VOLTAGE: 12.8 V - Control Module Voltage
===END ACM DTC U3000:49-2F===

===ACM DTC B1A56:15-2F===
Code: B1A56 - Antenna

Additional Fault Symptom (:15):
 - Circuit Short To Battery Or Open

Status (-2F):
 - DTC Present at Time of Request
 - Malfunction Indicator Lamp is Off for this DTC

Module: Audio Control Module

 Freeze Frame  #1:
-EVENT_TIME: 24746685 s - Event time
===END ACM DTC B1A56:15-2F===

===BCMii DTC B1097:14-0A===
Code: B1097 - Heated Windshield Relay

Additional Fault Symptom (:14):
 - Circuit Short To Ground Or Open

Status (-0A):
 - DTC Present at Time of Request
 - Malfunction Indicator Lamp is Off for this DTC

Module: Body Control Module

===END BCMii DTC B1097:14-0A===

===BCMii DTC B1C45:24-0A===
Code: B1C45 - Front Wiper Park Position Switch

Additional Fault Symptom (:24):
 - Signal Stuck High

Status (-0A):
 - DTC Present at Time of Request
 - Malfunction Indicator Lamp is Off for this DTC

Module: Body Control Module

===END BCMii DTC B1C45:24-0A===

===PCM DTC P0646:00-2D===
Code: P0646 - A/C Clutch Relay Control Circuit Low

Status (-2D):
 - DTC Present at Time of Request
 - Malfunction Indicator Lamp is Off for this DTC

Module: Powertrain Control Module

 Freeze Frame  #1:
-EVENT_TIME: 22371038 s - Event time
-TOTAL_DISTANCE: 163649 km - Total Distance
-MODULE_VOLTAGE: 12.0 V - Control Module Voltage
===END PCM DTC P0646:00-2D===

===PCM DTC P0504:00-28===
Code: P0504 - Brake Switch A/B Correlation

Status (-28):
 - Previously Set DTC - Not Present at Time of Request
 - Malfunction Indicator Lamp is Off for this DTC

Module: Powertrain Control Module

 Freeze Frame  #1:
-EVENT_TIME: 22539342 s - Event time
-TOTAL_DISTANCE: 163651 km - Total Distance
-MODULE_VOLTAGE: 14.3 V - Control Module Voltage

 Freeze Frame  #2:
-EVENT_TIME: 23561012 s - Event time
-TOTAL_DISTANCE: 163653 km - Total Distance
-MODULE_VOLTAGE: 14.5 V - Control Module Voltage
===END PCM DTC P0504:00-28===

===OBDII DTC None===
Successful DTC reading, no error codes found

Module: On Board Diagnostic II

===END OBDII DTC None===

===ABS DTC None===
Successful DTC reading, no error codes found

Module: Antilock braking system

===END ABS DTC None===

===RCM DTC None===
Successful DTC reading, no error codes found

Module: Restraint Control Module

===END RCM DTC None===

===PSCM DTC None===
Successful DTC reading, no error codes found

Module: Power Steering Control Module

===END PSCM DTC None===

===IPC DTC B10EA:00-6C===
Code: B10EA - Positive temperature coefficient heater

Status (-6C):
 - DTC Maturing - Intermittent at Time of Request
 - Malfunction Indicator Lamp is Off for this DTC
 - Test not complete

Module: Instrument Panel Control Module

===END IPC DTC B10EA:00-6C===

 

Time to get the multimeter out and start testing the Canbus systems. Both MS and HS should each read 60 Ohm.

There is one 120 Ohm resistor fitted across each pair of canbus wires at the start and finish of the network. So in effect two 120 resistors are fitted in parallel. If there is a break in the wiring then you will only read across one of the resistors which would give a value of 120 instead of 60 Ohms.

 

On 12/25/2024 at 11:41 AM, unofix said:

 

 

I ought to say that my IT tech son has untaken the work, recovering the software and loading it on the S/H unit and... everything works just fine and we're back on the road. Son 10 points, garage nil points.