Immobiliser fault

[Bogwoppit32]

Hi all
2011 Citroen c3 1.6 hdi exclusive .
Where to start ? .
I bought this car as a non runner with an immobiliser fault .
Dipped beam and brake lights are on when the ignition is on even if the lights are turned off .
No noise when key in ignition and door open .
When I try and do a global test with lexia this appears the vehicle is not triggered confirm on the diagnostic tool in this case .
A global test will be carried out .
Some of the ECU,s will not respond
Communication error with
Abs
Power steering
Multiplexed additive pump
Air bag
Switch module under steering wheel
Alarm .
.
I have had many c3,s with similar faults to this and a ECU ,bsi ,bcm, keys ,swap will sort them out with a little programming to get air con , fan ect correct but not this time .
I done a complete ECU kit swap and exactly the same faults return .
I am now at a loss and hope someone has seen this before .
It Is as if the bsi / ECU isn't seeing the key .
I have a list of faults from the bsi and ECU if this will help with the diagnosis .
I have never been beaten by a c3 before and don't intend on this being the first .
It seams to me as this is a wiring fault rather than hardware fault but any help is greatly appreciated .
Many thanks Dean

[Arfur Dent]

Hi

If you have swapped the BSI, ECU, BSM and the key, then unless you have faults on the other ECUs that won't communicate, that only leaves the interconnection between them.

As you suggest, I would suspect a wiring fault if swapping the parts out didn't fix it.


Try disconnecting the ECUs that report faults (no Comms) and see if you can talk to the others, reconnecting the faulty ones, one at a time to see if you can find one dragging down the bus.

[Bogwoppit32]

brilliant , I will give this a try tomorrow .
Thankyou very much for your time and thoughts .

[Bogwoppit32]

Sooo , I unplugged everything that was showing no Comms the only thing I noticed was with the abs module unplugged there was no Comms with the engine ECU .
Plug the abs back in and the engine ECU will then communicate .
It didn't matter what order I plugged all the others back in no Comms with any of them .
Could this be because the ECU isn't seeing the key ?? .
Is there a wire that transfers key code to the engine ECU ? And then back ? .
This car is starting to look like a garden car for bits .

[Bogwoppit32]

I can remember lexia saying something about it may not communicate with all the ECU because if the vehicle is not triggered , confirm on the diagnostic tool .
In this case a global test will be carried out some of the ECU,s will not respond .
Also it is saying engine control unit locked transponder label not recognised , this is the same message with 2 different ECU kits

[C3CAR]

Also it is saying engine control unit locked transponder label not recognised , this is the same message with 2 different ECU kits

Do you have a spare transponder ring from those kits?

It sounds like the ECU is not seeing the transponder in the key, so this could be due to the KEY, the ECU, the COM2000, the transponder ring or the communication between them.

[C3CAR]

Could this be because the ECU isn't seeing the key ?? .
Is there a wire that transfers key code to the engine ECU ? And then back ? .
This car is starting to look like a garden car for bits .

No, you can get all the ECUs communicating without a transponder acknowledgement

The communication is over the CAN BSU, so no individual wire, apart from the connection between the transponder ring and the COM2000

[Bogwoppit32]

I have tried another transponder ring and a good com2000 unit .
No difference .
How does the key code go from the com 2000 unit to the bsi then to the ECU and back to the bsi ? .
Must be via wires ? .
Maybe one of these could be broken .
I've visually inspected the pins on ECU and all good , no corrosion or broken pins as I have had this before .
At a loss as to what to do next really .
In the immobiliser information in ECU standard parameters it says as follows .
Control unit condition ECU locked
Status of the coded immobiliser programming cmm matched ( first time )
Problems detected when transmitting the unlock code awaiting response from bsi .
It does this with both ECU kits .

[C3CAR]

How does the key code go from the com 2000 unit to the bsi then to the ECU and back to the bsi ? .
Must be via wires ? .

It goes over the BUS.

If the BUS is broken, none of the ECUs will communicate.

[Ozvtr]

Hi all
2011 Citroen c3 1.6 hdi exclusive .
Where to start ? .
I bought this car as a non runner with an immobiliser fault .
Dipped beam and brake lights are on when the ignition is on even if the lights are turned off .
No noise when key in ignition and door open .
When I try and do a global test with lexia this appears the vehicle is not triggered confirm on the diagnostic tool in this case .
A global test will be carried out .
Some of the ECU,s will not respond
Communication error with
Abs
Power steering
Multiplexed additive pump
Air bag
Switch module under steering wheel
Alarm .
.
I have had many c3,s with similar faults to this and a ECU ,bsi ,bcm, keys ,swap will sort them out with a little programming to get air con , fan ect correct but not this time .
I done a complete ECU kit swap and exactly the same faults return .
I am now at a loss and hope someone has seen this before .
It Is as if the bsi / ECU isn't seeing the key .
I have a list of faults from the bsi and ECU if this will help with the diagnosis .
I have never been beaten by a c3 before and don't intend on this being the first .
It seams to me as this is a wiring fault rather than hardware fault but any help is greatly appreciated .
Many thanks Dean

This doesn't make a lot of sense.
It looks like the only bus working is the comfort VAN bus
The pre 2006 C3's had 2 bus structures and 4 separate BUSes. The CAN BUS and VAN BUS(es). There is 1 CAN bus and 3 VAN BUSes. The body VAN1, the body VAN2 and the comfort VAN.
The engine ECU, the power steering ECU and the ABS/ESP ECU are on the CAN BUS.
The Switching ECU (Coms 2000), airbag ECU and engine bay fusebox are on the body VAN1 BUS.
The sun/rain sensor and alarm are on the body VAN2 BUS.
The Cd/radio, cd changer, multifunction (central) display, dash display, aircon panel/ECU and parking assist ECU are on the comfort VAN BUS.
I cant think of a single point of failure that would wipe out 3 of the 4 buses and it not be the BSI.
The engine ECU communications runs through the ABS ECU. so unplugging the ABS ECU severs the encine ECU comms.
I would start by checking ALL the fuses with the ignition switch in the 'ignition' position. Tell us where you do and where you don't have power.
Check the physical condition of the earth connection from the battery to the engine and chassis.