This LRO reader emailed LRO.firstname.lastname@example.org to ask Julian Gilling for advice on how to deal with a troublesome immobiliser on his Range Rover P38.
The alarm on my Range Rover P38 V8 went off, which was odd as it hadn’t happened before. I reset it and went to bed. Next morning, it wouldn’t start. It turned over perfectly normally but that was it. Taking the initiative, I replaced the battery, reset it with the emergency key access code and off I went. Great – until the following day when it was back to cranking but no firing. The auto electricians I have tried can read an alarm fault but that’s all that shows. The car won’t fuel and won’t spark – it’s dead.
I tried the Body Electric Control Module (BeCM) again but that was checked and it was all in order. When the driver’s door handle was taken of it fell to bits. I know there are microswitches in there, so it was replaced by a secondhand unit. However, I’m still in the same situation, flipping between total lockout and engine immobilised to turning over and not starting. What’s going on?
Mike Hawkes, Barry, Glamorgan
Sounds like the immobiliser is losing sync with the engine. It could be the driver’s door latch, which has two microswitches in it. If the one that tells the BeCM the door is closed has poor contacts it will misinform the alarm that the door is being opened and closed, until the code from the key and the code from the engine no longer match and the immobiliser will kick in.
This can be remedied with Syncmate, available online for around £150. Look at the latches – they can be dismantled carefully. Clean all moving parts: if someone has used grease in the past they will stick. Another cause can be the remote sensor, which can pick up dodgy signals from wi-fi . This can be sorted by accessing the black box receiver below the driver’s side parcel shelf support panel and unplugging the blue wire. This will reduce the remote range to 3ft from the window, however.
This workshop advice appeared in the Feb 2015 issue of LRO. Back issues are available to download on digital devices here.