Ford S Max Body Control Module tech question
Discussion
Hi, Hoping for a bit of help here...
My 2009 2.0 TDCI Ford S Max has developed an unusual issue - I have the left (UK near side) rear light and left (UK near side) front position lamp not coming on. The lamps are definitely ok and there doesn't seem to be a wiring issue - I know this because I followed the advice about disconnecting the battery for 10 minutes in the hope of clearing the issue. On reconnecting the battery they light briefly, then go out and don't come back on with the other lights (on the other side).
From my research I reckon the fault is with the Body Control Module (BCM) located under the glove compartment. So I sourced a BCM from a breakers (same model) but when I fit it I get an engine immobiliser message. From what I can tell I can reprogram the key to get round the engine immobiliser issue but am worried that I'm going too far and am going to do more harm that good!
Can anyone advise me?
Very grateful for your suggestions. I'll answer any questions I can :-)
My 2009 2.0 TDCI Ford S Max has developed an unusual issue - I have the left (UK near side) rear light and left (UK near side) front position lamp not coming on. The lamps are definitely ok and there doesn't seem to be a wiring issue - I know this because I followed the advice about disconnecting the battery for 10 minutes in the hope of clearing the issue. On reconnecting the battery they light briefly, then go out and don't come back on with the other lights (on the other side).
From my research I reckon the fault is with the Body Control Module (BCM) located under the glove compartment. So I sourced a BCM from a breakers (same model) but when I fit it I get an engine immobiliser message. From what I can tell I can reprogram the key to get round the engine immobiliser issue but am worried that I'm going too far and am going to do more harm that good!
Can anyone advise me?
Very grateful for your suggestions. I'll answer any questions I can :-)
I have had the same issue on the same vehicle before (though it was the offside front and rear sidelights not working). I too traced this to a faulty body control module (or GEM in Ford speak). Traced wiring to GEM, applied feed there and sidelights worked.
Fault was traced to incorrect bulb in offside rear light unit (single filament rather than twin). Replaced bulb, still didn’t work. I also tried disconnecting the battery and retrying. Finally plugged into GEM and cleared stored DTCs (1 was relating to offside sidelights), this fixed the fault. I presume circuit was overloaded by the 21 watt bulb and tripped an internal safety feature in the GEM as the circuit doesn’t appear to directly fused.
To replace the GEM will be a pain for a non-Ford authorised repairer as access to EDIS etc. will be required. I’m sure someone in the aftermarket could do this. It may be easier to swap the EEPROM from one GEM to the other!
I would try communicating with the module and clearing all stored faults and retrying.
Regards.
Fault was traced to incorrect bulb in offside rear light unit (single filament rather than twin). Replaced bulb, still didn’t work. I also tried disconnecting the battery and retrying. Finally plugged into GEM and cleared stored DTCs (1 was relating to offside sidelights), this fixed the fault. I presume circuit was overloaded by the 21 watt bulb and tripped an internal safety feature in the GEM as the circuit doesn’t appear to directly fused.
To replace the GEM will be a pain for a non-Ford authorised repairer as access to EDIS etc. will be required. I’m sure someone in the aftermarket could do this. It may be easier to swap the EEPROM from one GEM to the other!
I would try communicating with the module and clearing all stored faults and retrying.
Regards.
Many thanks for your help. Can I ask a follow-up question?
I've changed the bulb again (just in case) with no effect. I have an OBD reader and it's showing no faults. My question is, how do I communicate with the BCM / GEM. I preume it's not with an OBD reader... Sorry if I'm being a bit thick!
I've changed the bulb again (just in case) with no effect. I have an OBD reader and it's showing no faults. My question is, how do I communicate with the BCM / GEM. I preume it's not with an OBD reader... Sorry if I'm being a bit thick!
FORScan may be able to clear any Codes.
It is OBD Software specifically for Ford and Mazda (I have a 2008 Mazda 6).
It goes a lot deeper than a standard OBD Reader.
https://forscan.org/download.html (Free)
Google for Forscan ELM327. It needs to be Forscan compatible with a Switch. About £10
I have the USB ELM327 and use on a Windows 10 Laptop.
The Bluetooth can be a bit flaky.
It is OBD Software specifically for Ford and Mazda (I have a 2008 Mazda 6).
It goes a lot deeper than a standard OBD Reader.
https://forscan.org/download.html (Free)
Google for Forscan ELM327. It needs to be Forscan compatible with a Switch. About £10
I have the USB ELM327 and use on a Windows 10 Laptop.
The Bluetooth can be a bit flaky.
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