My partner inherited a bit of an untidy Citroen C4, 1.6 diesel 08. No problems for the first two months, then when my partner was away for the weekend she was under the impression that the battery was flat as it wouldn't start. She tried jump leads, but that didn't work, but a friendly person with some break experience got it started. Checked the battery and alternator and believed they were fine, but didn't mention or spot an issue with the immobiliser.

Fast forward and the car has been not used for over a week, so she decided to start it and give it a reasonable drive. The car wouldn't start, but there didn't sound like any attempt for the engine to crank. Lights come on, as does radio, wipers etc all at once, which led me to believe the battery was ok, or if it didn't have enough charge it may give a feeble crank of the engine.

This led me to believe that there may be a problem with the immobiliser and my partner did spot a fault message in french regarding anti theft. I did disconnect the battery, as this helped with an old clio I owned, but no luck. The person we inherited it from said not to use the key which had the door unlock function, which she had done by accident, but instead just to use the physical key which normally worked. This key has no chip in it, and we can get in the car and use electronic functions.

Just wondering what simple things we could attempt before we need further assistance. I have cleaned up the key, disconnected the battery, tried to lock and unlock the door slowly a few times but no luck. She does have AA cover, but I need to see if her membership includes key/immobiliser issues.

Any ideas are much appreciated.