Immobiliser fault

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My Name: Ozvtr

Posts: 1199
Joined: Wed Jul 10, 2019 3:31 am
Model: C3 2002-2005, Original shape model
Year: 2003 (53)
Engine Size: 1.4 (8v)
Fuel Type: Petrol
Mileage: 80000
Trim Level: Other
Gearbox: Automatic PRND
Engine name: TU3 (75 PS)
Location: Brisbane, Australia.
Has thanked: 59 times
Been thanked: 351 times


Bogwoppit32 wrote: Wed Dec 08, 2021 8:38 pm 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 .
At start up the BSI contacts the COMs unit (the ECU with the selector stalks on it), the COMs uses the 'HF module' to transmit a signal out through the transponder ring antenna around the key lock. The transponder in the key responds to this signal with a radio frequency modulated code. That code is picked up by the antenna ring, demodulated by the HF module, and sent to the BSI via the COMs unit. The BSI sends that code on to the engine ECU. If the engine ECU recognizes the code then the engine ECU manages the running of the engine. If the engine ECU does not recognize the code, it does nothing.
My Name: Bogwoppit32

Posts: 21
Joined: Wed Oct 28, 2015 6:11 pm
Model: C3 2002-2005, Original shape model
Year: 2003 (03)
Engine Size: 1.4 (16v)
Fuel Type: Diesel
Mileage: 110000
Trim Level: Exclusive
Gearbox: Manual 5 speed
Been thanked: 1 time


:D hi, thankyou for all the help .
I went back out and had another go at after having a read up on can bus as I have never delved into this before .
One comment said it sounded like the bus was corrupted .
So I disconnected everything again and worked my way through it .
When inspecting the air bag ECU under the centre consul it had what smells like a can of coke spilt on it .
So I removed it and 2 of the pins were snapped and others were wet and sticky .
I removed the broken pins from plug and replaced it with one I had from a car I broke some time ago .
Reassembled everything and it started first time with no lights or warnings .
Thankyou for all your help .
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