My 2019 C5 Aircross has developed a fault, when I lock the car using the remote key fob the alarm activates.
The exact sequence is:-
1. Press ‘lock’ button on remote.
2. Car doors lock.
3. After 45 seconds or so indicator lights flash once.
4. About 5 seconds later the alarm sounds.
I understand that the interior alarm is armed after 45 seconds so thought that could be the cause. To check I disabled the interior alarm and tried again, no difference!
Has anyone had any similar issues please?
My local garage was good enough to put it on their Bosch Esitronic machine to read the fault codes and it came up with the following:-
MID 7.1
U1FA0 Touch Screen LVDS communication error
Rear Lid actuation 7.0
B1003 Control unit : Configuration - Configuration incorrect
Central electronics CE 7.0
B1808 Immobilizer : Release signal - No communication
B133D Window Lifter relay Down (Front window lifter relay) - open circuit
B1209 Cruise control: Operation message - Signal improbable
The garage suggested that the tailgate microswitch may be suspect and that the BSI should also be reset.
The other suggestions were key fob battery low or car battery low.
I have fully charged the battery (over the long weekend) - no difference.
Tried the spare key fob that has never been used - no difference.
Reset the BSI - no difference.
Uploaded the latest firmware and map data from Citroen - no difference.
Stripped down and resistance tested the tailgate locking mechanism and microswitch - no difference.
C5 Aircross alarm sounds when using key fob.
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Juan Sheet
- Posts: 1430
- Joined: Sat Dec 04, 2021 4:59 pm
Your mechanic's diagnostic tool is not able to provide the complete fault codes as they are missing the last 2 digits - which tells me he's not using Diagbox (Citroen's official software) that's for sure.
B1808 87 Means there is a fault in the unlocking of the immobiliser by the engine management ECU: Request missing. No engine management ECU unlocking request received by the built-in systems interface during the main or partial triggering phase for 4 seconds (Engine management ECU locked).
B133D 11 or 15 means a detection of an electrical fault on the front electric window relay control line: Open circuit or Short-circuit to earth in controlled mode.
B1003 55 can have several possibilities - but are to do with the NAC Connected Navigation system reporting an incorrect configuration during a diagnostic session, so it's possible your mechanic's diagnostic tools have caused or left it in this state.
U1FA0 00 is self-explanatory - there's a response time lag - but I'd ignore this one for now as it's low priority.
The B1209 also can have additional digits, but these relate to incoherent or invalid signal faults.
If you want my advice with the number of these issues, I would pay Citroen £120 Inc. VAT which will cover you for up to an hour of diagnostic time, as you really need their systems and guided diagnostics to determine the issue - or you could end up paying this to third party garages without them really knowing what's going on.
B1808 87 Means there is a fault in the unlocking of the immobiliser by the engine management ECU: Request missing. No engine management ECU unlocking request received by the built-in systems interface during the main or partial triggering phase for 4 seconds (Engine management ECU locked).
B133D 11 or 15 means a detection of an electrical fault on the front electric window relay control line: Open circuit or Short-circuit to earth in controlled mode.
B1003 55 can have several possibilities - but are to do with the NAC Connected Navigation system reporting an incorrect configuration during a diagnostic session, so it's possible your mechanic's diagnostic tools have caused or left it in this state.
U1FA0 00 is self-explanatory - there's a response time lag - but I'd ignore this one for now as it's low priority.
The B1209 also can have additional digits, but these relate to incoherent or invalid signal faults.
If you want my advice with the number of these issues, I would pay Citroen £120 Inc. VAT which will cover you for up to an hour of diagnostic time, as you really need their systems and guided diagnostics to determine the issue - or you could end up paying this to third party garages without them really knowing what's going on.
After waiting two months for a diagnostic check-up appointment at my local Citroen dealer I have just received a call to tell me that the diagnostic technician has gone on long-term sick with no return date.
Apart from the fact that appointments were so difficult to get why do they only have one trained technician!
Anyhow, rant over, can anybody tell me where the alarm module is located on the C5 Aircross and is it easy to access it?
Apart from the fact that appointments were so difficult to get why do they only have one trained technician!
Anyhow, rant over, can anybody tell me where the alarm module is located on the C5 Aircross and is it easy to access it?
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Juan Sheet
- Posts: 1430
- Joined: Sat Dec 04, 2021 4:59 pm
Not really, as the alarm module (ECU) is designed to be hard to access by its very nature.. It is located inside the depths of the dashboard somewhere, so not easy to access and the intrusion sensors are wired to this along with the bonnet sensor. The siren module which has it's own power reserve is in the engine bay hidden away and this also is wired to the ECU.
As for the technician - it depends on the franchise - they may not have more than one specialist if its a smaller dealership - staff will depend on the owner to be honest. It can take a lot of training to become familiar with all the systems on these vehicles - not an easy job to do ad-hoc, so they often specialise. I know this doesn't help you though.
As for the technician - it depends on the franchise - they may not have more than one specialist if its a smaller dealership - staff will depend on the owner to be honest. It can take a lot of training to become familiar with all the systems on these vehicles - not an easy job to do ad-hoc, so they often specialise. I know this doesn't help you though.
Hello,
Sorry for the delay.
I did try to get the Citroen garage to do a diagnostic check but they could not provide a date as their technician went on long term sick.
I bought a NOCO Genius 5 battery charger to attempt to repair the battery charge, tried twice but battery is not good.
After a full charge the battery voltage is 12.23v but after five minutes of switching on the electrics (without engine running) it drops to 12.1v.
My next attempt will be to get a new car battery fitted and test alarm again, I’ll keep you posted on the result.
Sorry for the delay.
I did try to get the Citroen garage to do a diagnostic check but they could not provide a date as their technician went on long term sick.
I bought a NOCO Genius 5 battery charger to attempt to repair the battery charge, tried twice but battery is not good.
After a full charge the battery voltage is 12.23v but after five minutes of switching on the electrics (without engine running) it drops to 12.1v.
My next attempt will be to get a new car battery fitted and test alarm again, I’ll keep you posted on the result.
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Juan Sheet
- Posts: 1430
- Joined: Sat Dec 04, 2021 4:59 pm
If your car battery is 5 years old or over, then it needs replacing.
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Juan Sheet
- Posts: 1430
- Joined: Sat Dec 04, 2021 4:59 pm
Ok, so for alarm triggering, on an older car, I would of suggested that the alarm siren module internal battery has discharged and therefore isn't holding a charge when armed, so is going off. But this seems too new a vehicle for that to happen already. So I think the issue has to be with those fault codes you previously posted earlier concerning B1808 Immobilizer : Release signal - No communication which may in itself be related to one of the other faults.
With this sort of issue, it really does need a dealer to look at it as it is not right and needs troubleshooting the electronic circuits and equipment.
With this sort of issue, it really does need a dealer to look at it as it is not right and needs troubleshooting the electronic circuits and equipment.
