K Series Immobiliser
Discussion
Hi all - after years of sitting in the garage, today was the day to MOT the 7 and get it back on the road. Except it's decided not to start (ran fine a week ago).
I'm pretty sure it's an immobiliser issue - it's a 1.8K series EU3. No fuel pump, no starter motor, but I have dash lights and headlights etc.
Can arm the immobiliser and get the steady red light blink, but when I disarm I'm getting a weird rapid blinking pattern (at one stage I was getting the immobiliser light to go out, but still no joy starting).
Battery is showing 12V and fuses for ECU and fuel pump look fine (have swapped the fuel pump fuse just in case).
Any clues as I've now missed the MOT and no further forward after 4 hours of trying
I'm pretty sure it's an immobiliser issue - it's a 1.8K series EU3. No fuel pump, no starter motor, but I have dash lights and headlights etc.
Can arm the immobiliser and get the steady red light blink, but when I disarm I'm getting a weird rapid blinking pattern (at one stage I was getting the immobiliser light to go out, but still no joy starting).
Battery is showing 12V and fuses for ECU and fuel pump look fine (have swapped the fuel pump fuse just in case).
Any clues as I've now missed the MOT and no further forward after 4 hours of trying
Hi Jo!
Sounds like the battery in the keyfob might be flat - try changing it. If you can get the light to go out again, then flick the master switch on and off two or three times as it will force the fuel pump prime cycle. Otherwise the car will be reluctant to start because there is no fuel in the fuel rail.
Sounds like the battery in the keyfob might be flat - try changing it. If you can get the light to go out again, then flick the master switch on and off two or three times as it will force the fuel pump prime cycle. Otherwise the car will be reluctant to start because there is no fuel in the fuel rail.
Hey Charles long time no speak! It's a road car now so no kill switch 
Spoke with Ronnie earlier and no, doesn't sound like an immobiliser issue (although he also said the double flashes are a symptom of low blipper battery). He wasn't sure either but suggested ignition circuit troubleshooting (as immobiliser doesn't do the cranking as you say) - car battery has plenty of juice, it's a weird one. ECU fuse is fine, fuel pump fuse fine, but he suggested the wire might be shot or the connector.
Doesn't seem to be power coming out of the MFRU which is weird.
Spoke with Ronnie earlier and no, doesn't sound like an immobiliser issue (although he also said the double flashes are a symptom of low blipper battery). He wasn't sure either but suggested ignition circuit troubleshooting (as immobiliser doesn't do the cranking as you say) - car battery has plenty of juice, it's a weird one. ECU fuse is fine, fuel pump fuse fine, but he suggested the wire might be shot or the connector.
Doesn't seem to be power coming out of the MFRU which is weird.
Some old document I have lying around said:
Rover K-Series Immobiliser Technical Note
Caterham 7 System Overview
The vehicle is fitted with an Alarm/Immobiliser Electronic Control Unit (ECU). This is the black (plastic) box mounted under the scuttle on the driver’s side. This unit is designed as an integrated alarm for a Rover saloon, with doors, central locking and all that stuff. For the Caterham application, the functionality is pared to the bare minimum – a Radio Frequency (RF) Remote operated immobiliser. This satisfies the SVA, and possibly insurance company, security requirements.
MEMS Robust Immobilisation
The Rover “Modular Engine Management System” (MEMS) will not allow the engine to start unless it receives the correct code from the immobiliser unit. The Immobiliser ECU is factory programmed with a random value as the “MEMS code”. On first communication with a virgin Engine Management System, the code is transmitted and the EMS permanently learns it. This means that the Immobiliser ECU and the EMS ECU must remain as a matched set. The scrutineers cannot swap system parts from car to car and expect them to function!
Any replacement immobiliser ECU must be programmed with the correct MEMS code, preferably obtained from reading the memory of the original unit.
The MEMS code is only required during cranking. Once the engine is running an immobiliser or communications failure cannot cause it to stop.
N.B. The crank disable function of the Immobiliser has NOT been implemented. This means that it is possible to crank the engine, but it will not actually start unless the Immobiliser has been disarmed. (Check whether the LED is on!).
Remote Key Operation
The RF Remote key fob has two buttons – Lock (padlock symbol) and Unlock (smooth).
With the Ignition OFF, pressing the Lock button will arm the system and immobilise the vehicle. The Confidence Confirm Telltale (CCT) LED will flash at 8Hz for 10s then reduce to a continuous 1Hz rate (one flash per second).
If the Ignition is switched ON without disarming the system, it thinks the vehicle is being hot-wired and goes into alarm mode. Fortunately, the horn is not connected so all you will hear is the ticking of the relay. At this point the vehicle is still immobilised and will NOT start.
The state of the alarm cannot be changed with Ignition ON, so pressing the Unlock button will NOT mobilise the car. You must turn Ignition OFF first, and then press the Unlock button. The CCT LED will go out. When Ignition is then turned ON, the LED will stay unlit and the vehicle should start.
Passive Arming
The system is equipped with an additional security feature, in that if the Ignition is turned OFF, but the Lock button is NOT pressed, it will arm itself after a set period of time. For a Rover tin-top, this period is 30s after Ignition Off AND door open. Obviously this isn’t much use as the Caterham doesn’t have door switches (or doors, for that matter). However, there is an additional timer that passively arms a set period after Ignition Off ONLY. The default value for this is 10 minutes.
For anyone who desires better security by having a shorter timeout – it can be done by reprogramming an option in the ECU. The minimum value is 8 seconds. This means you would be able to turn the Ignition Off, exit the vehicle and the Immobiliser would have armed itself BEFORE you pull the plug by removing the FIA switch. No need to press the Lock button.
If the system has passively immobilised, and the Ignition is turned On, the CCT LED will be illuminated continuously to indicate that the vehicle is immobile. Note the point above that the engine will still crank. If you are having problems starting, make sure the LED is OFF!
At this point simply press the Unlock button to turn the immobiliser off. This is the only time the ECU will recognise a RF signal with Ignition On.
FIA Switch – Battery Disconnection
The FIA switch disconnects all power to the vehicle – including the Immobiliser. The ECU detects the power down and stores its current status. When you switch on again, the ECU restores the previous immobilisation state. Unfortunately, with the default 10 minute timeout, this means a prospective thief has plenty of time to start the car before it passively immobilises. Remember, once the engine has been successfully started, the status of the immobiliser doesn’t matter.
Key Re-Synchronisation
A Rover car would not normally be subject to regular battery disconnection, so there is a slight problem if you use the big red switch as a matter of course. When the power is re-connected, the key fob must be pressed FOUR times to re-synchronise it with the ECU.
N.B. There is an option available to remove the necessity for multiple presses, such that the system re-synchronises on the first press. This involves reprogramming the ECU. This option is slightly less secure, but it would take a well tooled-up professional thief to notice the difference!
It would appear that some Caterham supplied units come with this option set as standard. Mine did not.
Caterham 7 System Overview
The vehicle is fitted with an Alarm/Immobiliser Electronic Control Unit (ECU). This is the black (plastic) box mounted under the scuttle on the driver’s side. This unit is designed as an integrated alarm for a Rover saloon, with doors, central locking and all that stuff. For the Caterham application, the functionality is pared to the bare minimum – a Radio Frequency (RF) Remote operated immobiliser. This satisfies the SVA, and possibly insurance company, security requirements.
MEMS Robust Immobilisation
The Rover “Modular Engine Management System” (MEMS) will not allow the engine to start unless it receives the correct code from the immobiliser unit. The Immobiliser ECU is factory programmed with a random value as the “MEMS code”. On first communication with a virgin Engine Management System, the code is transmitted and the EMS permanently learns it. This means that the Immobiliser ECU and the EMS ECU must remain as a matched set. The scrutineers cannot swap system parts from car to car and expect them to function!
Any replacement immobiliser ECU must be programmed with the correct MEMS code, preferably obtained from reading the memory of the original unit.
The MEMS code is only required during cranking. Once the engine is running an immobiliser or communications failure cannot cause it to stop.
N.B. The crank disable function of the Immobiliser has NOT been implemented. This means that it is possible to crank the engine, but it will not actually start unless the Immobiliser has been disarmed. (Check whether the LED is on!).
Remote Key Operation
The RF Remote key fob has two buttons – Lock (padlock symbol) and Unlock (smooth).
With the Ignition OFF, pressing the Lock button will arm the system and immobilise the vehicle. The Confidence Confirm Telltale (CCT) LED will flash at 8Hz for 10s then reduce to a continuous 1Hz rate (one flash per second).
If the Ignition is switched ON without disarming the system, it thinks the vehicle is being hot-wired and goes into alarm mode. Fortunately, the horn is not connected so all you will hear is the ticking of the relay. At this point the vehicle is still immobilised and will NOT start.
The state of the alarm cannot be changed with Ignition ON, so pressing the Unlock button will NOT mobilise the car. You must turn Ignition OFF first, and then press the Unlock button. The CCT LED will go out. When Ignition is then turned ON, the LED will stay unlit and the vehicle should start.
Passive Arming
The system is equipped with an additional security feature, in that if the Ignition is turned OFF, but the Lock button is NOT pressed, it will arm itself after a set period of time. For a Rover tin-top, this period is 30s after Ignition Off AND door open. Obviously this isn’t much use as the Caterham doesn’t have door switches (or doors, for that matter). However, there is an additional timer that passively arms a set period after Ignition Off ONLY. The default value for this is 10 minutes.
For anyone who desires better security by having a shorter timeout – it can be done by reprogramming an option in the ECU. The minimum value is 8 seconds. This means you would be able to turn the Ignition Off, exit the vehicle and the Immobiliser would have armed itself BEFORE you pull the plug by removing the FIA switch. No need to press the Lock button.
If the system has passively immobilised, and the Ignition is turned On, the CCT LED will be illuminated continuously to indicate that the vehicle is immobile. Note the point above that the engine will still crank. If you are having problems starting, make sure the LED is OFF!
At this point simply press the Unlock button to turn the immobiliser off. This is the only time the ECU will recognise a RF signal with Ignition On.
FIA Switch – Battery Disconnection
The FIA switch disconnects all power to the vehicle – including the Immobiliser. The ECU detects the power down and stores its current status. When you switch on again, the ECU restores the previous immobilisation state. Unfortunately, with the default 10 minute timeout, this means a prospective thief has plenty of time to start the car before it passively immobilises. Remember, once the engine has been successfully started, the status of the immobiliser doesn’t matter.
Key Re-Synchronisation
A Rover car would not normally be subject to regular battery disconnection, so there is a slight problem if you use the big red switch as a matter of course. When the power is re-connected, the key fob must be pressed FOUR times to re-synchronise it with the ECU.
N.B. There is an option available to remove the necessity for multiple presses, such that the system re-synchronises on the first press. This involves reprogramming the ECU. This option is slightly less secure, but it would take a well tooled-up professional thief to notice the difference!
It would appear that some Caterham supplied units come with this option set as standard. Mine did not.
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