revilla

The Lucas 5AS immobiliser used on K Series Caterhams is now supported by my MEMS3 Tools suite. Although the Caterham doesn't use a lot of the functionality of the 5AS, the ability to pair new key fobs is definitely useful. All free, other than for the cost of a cheap cable, as always (although this time there's just a small change needed to the cable). Here's the page I just posted on my own website ... Support Added for the Lucas 5AS Immobiliser Download Link: https://andrewrevill.co.uk/Downloads/MEMS3Tools.zip As of Version 7.91, MEMS3 Mapper now supports the Lucas 5AS immobiliser. Having recently added support for the earlier families of MEMS ECUs, I decided for completeness would add support for the Lucas 5AS immobiliser. Some years ago, I did a lot of work deciphering the internals of this immobiliser, but I didn’t get around to working out the communications protocols it uses. Now, armed with the knowledge gained from work on the ECUs and helped by work done by James Portman at rovermems.com, I decided I was in a position to do a proper job of supporting the immobiliser to the same level as the ECU families. One of the most useful features available is the ability to PAIR KEY FOBS WITH THE IMMOBILISER. The Lucas 5AS Tools Application You can simply select the Lucas 5AS Immobiliser from the list of ECU families: This pops up what looks like a regular dialog box, but it’s actually a separate application that supports the immobiliser rather than engine ECUs. You will see there are now two application icons on the taskbar. You can run this application on its own it you want. In the root folder of the MEMS3 Tools installation there’s a launcher file Lucas 5AS Tools - For Lucas 5AS Immobilisers Only.exe which you can double-click to launch it as a standalone application. It’s written in very much the same style as the other applications in my MEMS3 Tools suite, so if you’re used to MEMS3 Mapper or MEMS Flasher, you will find it all very familiar. If not, it’s very straightforward to find your way around. At the top of the window you can select the COM port or FTDI device which corresponds to your diagnostic cable (but see the section on Diagnostic Cable required below, as the requirements are slightly different to the other ECU families and you will need a slightly different cable for the Lucas 5AS immobiliser). · The About 5AS button will connect to the 5AS and display the model name and serial number (where available – some features are only supported on Model Year 98 onwards units). · The Read button enables you to read the setting memory from a 5AS, after which you can edit the various settings in the Fields tab: · The Verify button allows you to compare the current project with the contents of the 5AS. This lets you check whether the file was read or written correctly (the messages sent between the PC and 5AS do not include any kind of checksum, so although they are generally reliable it’s always a good idea to verify). · The Write button allows you to write modified settings back to a 5AS. · The Save and Open buttons allow you to save 5AS projects to file, or open a previously saved project. · The Hex tab lets you see the raw hexadecimal data read from the 5AS. You should not normally edit the data directly, but by changing settings in the Fields tab. The 5AS isn’t entirely tolerant of invalid data being written and it is possible to brick the units by writing data which it can’t understand: · The Log tab shows the details of the communications between the PC and the 5AS. This can be helpful in diagnosing communications problems: · The Live Diagnostics tab gives you live data from the 5AS. Click the Live Diagnostics button on this tab to start the live diagnostics running, then click Done when you’re finished. This includes some fairly static information such as serial number and Emergency Key Access (EKA) code, but also a live view of the various switch inputs the 5AS can see. There is also some live information about the key fobs, including the number of key presses it has detected from each of the key fobs paired. Note that these counts are only valid immediately after pressing a key fob button as the fields may be used for other purposes at other times, but it’s useful for testing key fobs for reliable operation. It also shows the code for the last key fob programmed, but again this is only valid immediately after programming. · The Tools menu gives access to a few tools for maintaining the 5AS, namely: o About 5AS – As described above. o EKA Code – This reads the Emergency Key Access (EKA) code from the 5AS and displays instructions on how to use it. Note that if you want to CHANGE the EKA code, you should read the 5AS, edit the EKA in the Fields tab and write back to the 5AS: o EMS Code – This reads the code sent to, and learned by, the MEMS ECU. If you want to want to replace the immobiliser without having to pair it again with the ECU, you can set the EMS code of the new immobiliser to match that of the old immobiliser and the ECU will see them as the same unit. The notes on CHANGING the EKA code above also apply to the EMS code: o Test Outputs – This lets you force 5AS outputs ON or OFF for test purposes. In the example below the 5AS is being told to turn the immobiliser chime (in the Multifunction Unit of a Rover) and the horn relay ON and the immobiliser energiser coil OFF. o Program Key Fobs – This allows you to program new or replacement key fobs into the 5AS: § Note that the programming procedure erases all keys currently paired, so you need to have all the keys you want paired to the 5AS handy before starting the process. § Press the LOCK button on each key fob repeatedly and steadily until the horn sounds. This will normally require 8 presses. If you’ve pressed the LOCK button more than 10 times and the horn still hasn’t sounded, the key fob is most likely faulty, the battery in the fob is flat, or the fob is not compatible with the 5AS unit. NB: On a Caterham the horn circuit is not connected to the 5AS unit, so it WILL NOT SOUND. There’s no harm in pressing the LOCK button more than 8 times. So, in this case I’d suggest pressing each LOCK button maybe 10 times for good measure, then testing the key fobs afterwards to make sure they paired correctly. If you waned to, you could connect a small bulb or 12V LED between the 12V supply and Pin 8 of the grey plug on the immobiliser; this will then flash briefly to represent the horn sounding. § When you’ve programmed all of the key fobs you want to use, click Done. You can program up to 4 key fobs into a single 5AS. Diagnostic Cable Required For the later MEMS ECU families, a cheap a readily available VAG COM KKL 409.1-style cable can be used. However, communications with the Lucas 5AS immobiliser are a little more complicated and it does require a special cable. I wanted to keep the requirements cheap and simple, so I’ve come up with a scheme that lets you convert a regular VAG COM KKL 409.1-style cable into a 5AS cable very quickly and cheaply. IF YOU DON’T WANT TO GET INVOLVED IN MODIFYING CABLES THEN JUST ASK ME – I’ll happily supply you with a suitable and cheap 5AS cable. The special requirements for the diagnostic cable are as follows: · The Lucas 5AS uses both the regular K Line and the L Line for communications. These are both supported by KKL cables (which actually means “K, or K & L”) but the 5AS sends the data back on the L Line logically inverted. A regular KKL cable does not expect this and cannot read the data. There are two ways of converting the cable to accept inverted received (RXD) data, depending on the chip your cable uses, which will normally be an FT232R or a CH340G (the adverts for the cable usually specify which): o If your cable contains a GENUINE FTDI FT232R chip, you can use the FT_PROG utility from FTDI here: https://ftdichip.com/utilities/#ft_prog. Click DEVICES, Scan & Parse to list the FTDI devices connected, identify the one which corresponds to your cable (if in doubt, unplug everything else) and then under Hardware Specific, Invert RS232 Signals check Invert RXD and then click DEVICES, Program. You should then completely unplug your cable and reconnect it to the PC to make the new setting take effect (until you do this it will continue to work as before, as the cable only loads these settings as it powers up). WARNING: Most cheap Chinese cables containing FT232R chips are actually FAKE. The above will only work with GENUINE FTDI devices. FTDI at one point released drivers which deliberately and permanently disabled fake chips, and the fake chip manufacturers responded by making their chips read-only. This means they usually work for the purpose for which they were intended, but cannot be programmed as described above. It will appear to work, but if you read the cable again you will find that nothing has been set. If you’re buying a cable specially to use with the 5AS, I would recommend buying a cable with a CH340G chip and using the next option … o If your cable contains a CH340G chip, you need to make one tiny modification. Find the CH340G chip and solder Pin 15 to Pin 16, as shown below. Note the small dot/indentation in the chip case which marks Pin 1. Pins 15 and 16 are opposite Pin 1. Make sure that Pin 15 is unconnected first. If Pin 15 appears to have a connection then you will need to desolder that pin and lift it clear of the board before soldering to Pin 16, but most boards I have seen leave Pin 15 unconnected. · The Lucas 5AS immobiliser usually uses Pin 3 of the OBDII connector for K Line instead of the usual Pin 7. It uses Pin 1 for L Line instead of the usual Pin 15. This allows the immobiliser and ECU to be connected to the same OBDII connector. The KKL cable will be talking to Pin 7 and listening on Pin 15, instead of talking on Pin 3 and listening on Pin 1. The diagram below shows the female OBDII socket as fitted to the car, seen from the front (or the male OBDII plug as installed on a cable, seen from the wiring side): The easiest way to fix this is to buy an OBDII extension cable of this design, which you can find for sale on eBay, Amazon and AliExpress: The little secondary locking tabs one either side of the male connectors on these can easily be popped open as shown below: This allows the terminals to be removed very easily by lifting the little plastic locating tangs with a needle or pin as shown below: All you need to do is remove Pin 3 and Pin 7 and put them back in swapped over, and similarly remove Pin 1 and Pin 15 and put them back in swapped over. If you do this only on the white female connector on the end cable (not the one in the middle), then you have a two-port adapter; the black male connector plugs into your car, the middle white female connector is for the MEMS ECU cable and the end white female connector is for the 5AS cable. They should be labelled with permanent marker or similar each cable will only work in the appropriate port. You can use this to plug either cable into your car, or even both at the same time as they will not conflict:

Good decision! Pretty sure I know what the gunge running down from the head joint is, seen it before. Stag Wellseal, it's a non-hardening bonding sealing compound used to bond steel saver shims used when the heads have gone soft. Basically tree resin in solvent. Horrible stuff and has a tendency to blow out down the sides like that. But the main thing about it is that it's only really used when the engine has issues.

MEMS 2J support now added. This covers EU2 VVC Caterhams. Original post updated to inlcude MEMS 2J.

I can't guess much from the pictures of the profiles. @oilyhands is the man! However as you say, with Piper Cams on the casting they're not stock Rover items. Genuine EU3 SuperSport cams with the half-moon sensor triggers are few and far between. My guess would be 633 spec too. But it is just a guess.

Mike, in case you haven't spotted it, analysis of your map in the comments here. It's a remapped 1600 SuperSport ECU:

Examples below of Miker7's VE table, a stock 1600 SuperSport VE table and a stock 1600 RoadSport VE table. I've spun them round so you can see the shape of the edge that corresponds to the RPM range at full MAP. This gives a pretty good idea of the shape of the torque curve of the engine. As you can see, the RoadSport starts to roll off at higher RPM where the SuperSport continues to climb, as expected. From this Miker7's is clearly a 1600 SuperSport ECU (the engine capacity scalar used in the air flow calcualtions is set to 1588cc). It's slightly different to the stock SuperSport because it's been remapped, but it's the same basic shape and quite different to the RoadSport. Miker7's VE Table: Example of a Stock 1600 SuperSport VE Table: Example of Stock 1600 RoadSport VE Table:

For MEMS3, you can distinguish a SuperSport ECU by looking at the VE table (basically a model of the air flow into the engine). The SuperSport curve (surface) is a very different shape because of the different engine breathing. There are plenty of examples of SuperSport maps in the library on my website so it's easy to compare an unknown with a couple of those and see which it looks like. Even if remapped by Kmaps it won't be that far different that you wouldn't recognise it. For MEMS1.9 my tool doesn't give you the ability to display the map visually as the table structure is just so different to MEMS3 (I may add something that converts them just for display purposes at some point). But it does let you read the map (full ROM) data and save it to a file and I have got a little table extractor program I wrote that will find the tables in there and then you can graph them in Excel. The resolution of the tables is a lot lower (byte not word) but other than for rounding errors, the EU2 and EU3 SuperSport VE tables are identical. That will confirm whether you have a SuperSport map or not. To confirm whether you have SuperSport cams is then easy - because a SuperSport engine on a regular map or a regular engine on a SuperSport map will run with the mixture so far wrong it's pretty obvious (I've had to diagnose a couple of where that was the problem and they really weren't happy). So if it runs nicely, then cams match the map. In terms of Miker7's thread ... I was sitting in a pub with him last week with ECUs out on the table. I really know how to enjoy myself LOL. I have a copy of his map, I'll try to post a comparison up on here in a bit to show what it is.

Yes it does. It's probably a MEMS 1.9. Compare it with the pictures at the top of the post to see what you've got.

Anyone with a pre-MEMS3 K Series Caterham (EU1 or EU2) can now use all of the live diagnostic, live data, live dashboard, fault code, immobiliser pairing and service adjustment features in MEMS3 Mapper. I've add the protocols and setups all of the previous MEMS versions (MEMS2J EU2 VVC still in progress, will be released shortly). All free, other than for the cost of a cheap cable, as always. Here's the page I just posted on my own website ... Full Support Added for All Rover MEMS ECU Families Download Link: https://andrewrevill.co.uk/Downloads/MEMS3Tools.zip As of Version 7.87, MEMS3 Mapper now fully supports all Rover MEMS ECU Families including 1.2 / 1.3 / 1.6 / 1.6 / 2J / 3 / EU4. Having recently used some other tools when helping people with issues on MEMS 1.9 EU2 cars, and having found them somewhat frustrating and expensive, I decided to add support for all of the earlier families of the Rover MEMS ECU into MEMS3 Mapper. These include the ECUs used on EU2 and earlier Caterhams, SPI Minis etc. (the full range of MEMS3 ECUs for both petrol and diesel were already fully supported). This turns “MEMS3 Mapper” into a true one-stop-shop for all Rover ECU support and maintenance tasks. The earlier ECUs are not OBDII compliant and some of them need a slightly different cable (a 3-pin ROSCO diagnostic cable) but these are also readily available. The earlier ECUs mostly use a different communications protocol (ROSCO “Rover Service Communications” instead of a variant of KWP2000) so all of the ECU interface had to be developed from scratch, but could be integrated into the existing user interface framework. The earlier ECUs are not remappable, however most of the diagnostic capabilities of MEMS3 Mapper can still be used with them and they all support a range of maintenance operations including immobiliser pairing and service adjustments. MEMS3 Mapper fully supports the capabilities provided by each ECU family. I owe a big “thank you” to James Portman at rovermems.com. James had already done most of the research one the earlier ECUs and had developed some online diagnostic tools for them. He shared all of this with me and actively encouraged and supported my endeavours in this. ECU Families Now Supported · Rover MEMS 1.2 - Used mainly on very early SPI cars without catalytic converters around 1991. · Rover MEMS 1.3 - Used mainly on early SPI cars from about 1992 to 1993. · Rover MEMS 1.6 - Used mainly on cars with Rover K-Series SPI and some early MPI engines. · (Caterham EU2 MPI) Rover MEMS 1.9 MKC EU2 MPI - Used on cars with Rover K-Series EU2 MPI engines. · (Caterham EU2 VVC) Rover MEMS 2J MKC EU2 VVC - Used on cars with Rover K-Series EU2 VVC engines and MPI Minis. · (Caterham EU3 MPI) Rover/Motorola MEMS3 NNN EU3 MPI with Lucas 5AS / Pektron - Used on cars with Rover K-Series MPI engines from about 2001 onward. · Rover/Motorola MEMS3 NNN EU3 MPI with BMW EWS 3.D - Used on Rover 75 / MGZT and Freelander cars with Rover K-Series MPI engines from about 2001 onward. · (Caterham EU3 VVC) Rover/Motorola MEMS3 NNN EU3 VVC with Lucas 5AS / Pektron - Used on cars with Rover K-Series VVC engines from about 2001 onward. · Rover/Motorola MEMS3 NNX XFW - Extended Firmware custom configuration introduced and supported by MEMS3 Mapper. · Rover/Continental MEMS3 NNN EU4 - Used on cars with NAC N-Series engines such as the MG TF LE500. · Land Rover/Lucas MEMS3 MSB 10P EU2 - Used mainly on Land Rover Discovery and Defender Td5 cars with the earlier 10P engine from around 1998 to 2002. · Land Rover/Lucas MEMS3 NNN 15P EU3 - Used mainly on Land Rover Discovery and Defender Td5 cars with the later 15P engine from around 2002 to 2004. Diagostic Cables Required · MEMS 1.2, 1,3 and 1.6 ECUs normally use a 3-pin ROSCO (Rover Service Communications) cable. These can be purchased here https://shop.jmpe.co.uk/products/rover-3-pin-ecu-diagnostic-connector. Other suppliers may be available online but this cable is tested and known to be working with these ECUs. Rover vehicles will have a corresponding diagnostic connector to plug this into, probably in the engine bay. Non-Rover vehicles may not be fitted with the connector, in which case you will need to wire this cable to the ECU yourself: o Pin 1 – Signal Ground – ECU Pin 14 o Pin 2 – ECU Data Out to PC Data In – ECU Pin 10 o Pin 3 – PC Data Out to ECU Data In – ECU Pin 15 · All other MEMS families normally use a VAG COM KKL 409.1 style OBDII cable. These can be found all over the web and on sites such as eBay but I’d recommend this one: https://shop.jmpe.co.uk/products/rover-16-pin-ecu-diagnostic-cable as it is tested and known to be working with these ECUs. Key Capabilities by ECU Family Rover MEMS 1.2 · ROSCO Protocol. · 3-Pin UART ROSCO Diagnostic Cable. · Reading and Saving of Full ROM (Firmware and Map). · Live Diagnostics o Live Data. o Live Fault Codes. o Live Dashboard. · Immobiliser Pairing & Status. · Clear Adaptations. · Service Adjustments. Rover MEMS 1.3 · ROSCO Protocol. · 3-Pin UART ROSCO Diagnostic Cable. · Reading and Saving of Full ROM (Firmware and Map). · Live Diagnostics o Live Data. o Live Fault Codes. o Live Dashboard. · Immobiliser Pairing & Status. · Clear Adaptations. · Service Adjustments. Rover MEMS 1.6 · ROSCO Protocol. · 3-Pin UART ROSCO Diagnostic Cable. · Reading and Saving of Full ROM (Firmware and Map). · Live Diagnostics o Live Data. o Live Fault Codes. o Live Dashboard. · Immobiliser Pairing & Status. · Clear Adaptations. · Service Adjustments. Rover MEMS 1.9 EU2 MKC EU2 MPI · ROSCO Protocol. · OBDII-Style K-Line Diagnostic Cable. · Reading and Saving of Full ROM (Firmware and Map). · Live Diagnostics o Live Data. o Live Fault Codes. o Live Dashboard. · Immobiliser Pairing & Status. · Clear Adaptations. · Service Adjustments. Rover MEMS 2J MKC EU2 VVC · KWP2000 Protocol. · OBDII-Style K-Line Diagnostic Cable. · Reading and Viewing of Map. · Live Diagnostics o Live Data. o Live Fault Codes. o Live Dashboard. · Immobiliser Pairing & Status. · Clear Adaptations. · Service Adjustments. Rover/Motorola MEMS3 NNN EU3 MPI with Lucas 5AS / Pektron · Rover/BMW Protocol. · KWP2000 Protocol. · OBDII-Style K-Line Diagnostic Cable. · Reading, Writing, Editing and Viewing of Firmware, Coding and Map. · Custom Firmware Patches. o Dual Map, Live Switching. o Live Mapping. o Debugging. o CAN Bus Logging. o CAN Bus Sniffing. · Map and Firmware Wizards. · Live Diagnostics o Live Data. o Live Fault Codes. o Freeze Frames. o Live Dashboard. · VIN and ZCS Coding. · Immobiliser Pairing & Status. · Clear Adaptations. · Service Adjustments. · Comprehensive ECU Maintenance Tools. Rover/Motorola MEMS3 NNN EU3 MPI with BMW EWS 3.D · Rover/BMW Protocol. · KWP2000 Protocol. · OBDII-Style K-Line Diagnostic Cable. · Reading, Writing, Editing and Viewing of Firmware, Coding and Map. · Custom Firmware Patches. o Dual Map, Live Switching. o Live Mapping. o Debugging. o CAN Bus Logging. o CAN Bus Sniffing. · Map and Firmware Wizards. · Live Diagnostics o Live Data. o Live Fault Codes. o Freeze Frames. o Live Dashboard. · Clear Adaptations. · Service Adjustments. · Comprehensive ECU Maintenance Tools. Rover/Motorola MEMS3 NNN EU3 VVC with Lucas 5AS / Pektron · Rover/BMW Protocol. · KWP2000 Protocol. · OBDII-Style K-Line Diagnostic Cable. · Reading, Writing, Editing and Viewing of Firmware, Coding and Map. · Custom Firmware Patches. o Dual Map, Live Switching. o Live Mapping. o Debugging. o CAN Bus Logging. o CAN Bus Sniffing. · Map and Firmware Wizards. · Live Diagnostics o Live Data. o Live Fault Codes. o Freeze Frames. o Live Dashboard. · VIN and ZCS Coding. · Immobiliser Pairing & Status. · Clear Adaptations. · Service Adjustments. · Comprehensive ECU Maintenance Tools. Rover/Motorola MEMS3 NNX XFW · Rover/BMW Protocol. · KWP2000 Protocol. · OBDII-Style K-Line Diagnostic Cable. · Reading, Writing, Editing and Viewing of Firmware, Coding and Map. · Custom Firmware Patches. o Dual Map, Live Switching. o Live Mapping. o Debugging. o CAN Bus Logging. o CAN Bus Sniffing. · Map and Firmware Wizards. · Live Diagnostics o Live Data. o Live Fault Codes. o Freeze Frames. o Live Dashboard. · VIN and ZCS Coding. · Immobiliser Pairing & Status. · Clear Adaptations. · Service Adjustments. · Comprehensive ECU Maintenance Tools. Rover/Continental MEMS3 NNN EU4 · Rover/BMW Protocol. · KWP2000 Protocol. · OBDII-Style K-Line Diagnostic Cable. · Reading, Writing, Editing and Viewing of Firmware and Map. · Custom Firmware Patches. o Dual Map, Live Switching. o Live Mapping. o Debugging. o CAN Bus Logging. o CAN Bus Sniffing. · Map and Firmware Wizards. · Live Diagnostics o Live Data. o Live Fault Codes. o Freeze Frames. o Live Dashboard. · VIN and ZCS Coding. · Immobiliser Pairing & Status. · Clear Adaptations. · Service Adjustments. · Comprehensive ECU Maintenance Tools. Land Rover/Lucas MEMS3 MSB 10P EU2 · Rover/BMW Protocol. · KWP2000 Protocol. · OBDII-Style K-Line Diagnostic Cable. · Reading and Viewing of Map. · Live Diagnostics o Live Data. o Live Fault Codes. o Live Dashboard. · Immobiliser Pairing & Status. · Clear Adaptations. · Service Adjustments. Land Rover/Lucas MEMS3 NNN 15P EU3 · Rover/BMW Protocol. · KWP2000 Protocol. · OBDII-Style K-Line Diagnostic Cable. · Reading, Writing, Editing and Viewing of Firmware, Coding and Map. · Custom Firmware Patches. o Dual Map, Live Switching. o CAN Bus Logging. · Map and Firmware Wizards. · Live Diagnostics o Live Data. o Live Fault Codes. o Live Dashboard. · VIN and ZCS Coding. · Immobiliser Pairing & Status. · Clear Adaptations. · Service Adjustments. · Comprehensive ECU Maintenance Tools.

Just a thought. There was another trick that people did. This one involved cutting a different wire. It's like diffusing a bomb! Some immobilisers had "passive arming". I'd yours has a MEMS1.9 it may be too early for this but maybe not, I think it came in for the 1997 model year. On those, if you didn't set the immobiliser on the key fob, it would start a countdown timer when you turned the ignition off and set itself after a period of time. There was a flaw though, the immobiliser had two power supply wires - one ignition switched, one permanent 12V. If you cut the permanent 12V supply, then when you turned the ignition off the whole immobiliser lost power and shut down immediately. So it never got to do the countdown and never armed itself. If that's how yours has been done, it could have somehow inadvertently armed itself again. Do you actually have key fobs for it? If so, worth seeing if you can disarm it on the fob, and it may then stay disarmed.

Hi, heard my name mentioned ... You can't really check the communications line between the 5AS and thr MEMS1.9 with a multimeter. It's a coded digital square wave signal. You need a logic probe or an oscilloscope really. How exactly was yours modified to run without the immobiliser? The 1.9 doesn't actually have a flag in the map to tell it not to look for an immobiliser (well, it may have, but you can't write to the map on them to change it so it effectively doesn't). What it does have is a sort of factory learning mode. In this mode it is looking for a valid immobiliser signal and when it sees one, it learns it and locks to that immobiliser. That made it easy to pair them up in production, you just put one MEMS1.9 and one 5AS in the car and they pair when first powered up. I think what people have tended to do as a hack is to put the ECU into learning mode and then cut the wire between the 5AS and the MEMS to make sure it never sees a signal. They often cut the pin internally, inside the ECU case.That way it stays in learning mode forever, and in that modenit will run. In theory! The problem is they have been found to occasionally interpret random noise picked up on the cut immobiliser line as a 5AS signal, learn it and lock onto it. That leaves them permanently immobilised. Actually grounding the pin rather than just cutting it and leaving it floating would be a safer bet I think. If that's what's happened, then you need to put the ECU back into learning mode. There are several tools out there that can do that, but none of them are probably worth buying for a one off. I've got the tools, if you wanted to send me the ECU an 5AS I could have a good look on the bench to see what's happening and sort them out for you? The other alternative is ... I'm just in the process of adding in all of the basic diagnostic features for MEMS1.9 into my MEMS3 tools suite. The full thing is not ready to go yet, but I could easily knock up a little Windows program that would just put the ECU into immobiliser learning mode. All you would need then would be a £7 cable off eBay. Let me know if you want me to help! Cheers, Andrew

Hi Elliott, Sorry, I didn't get a notification of your reply for some reason so I missed it. Send me your address and you can have it 🙂 Andrew

Is this any good?

I might actually have one of those. I'll have a look in the morning.

7V during cranking is very low. But the real killer will be the inrush current spike as the motor first starts, which will drop a lot lower. You can't see it on a multimeter, it's too short lived, maybe 0.1 seconds - you need an oscilloscope. I recently did some work for a tuner who wanted me to include a low voltage warning in my tools when programming an ECU. I have a very good digital programmable power supply for my bench harness that lets me adjust the supply voltage in 10mV steps, so I have a play around to just how low a steady state power supply voltage the ECU would run normally on. The answer is a surprising 6.6V! I think it's the point where the internal 5V regulator drops out. Anywhere above that, the ECU was running normally, including for programming purposes. At 7V you are very close, and any inrush current spike is going to take you well below. If you're hearing the IACV after turning off the ignition key, that's normal. If you're hearing it just after releasing from cranking, that's not, and it's a prety sure sign that the ECU is dropping out during cranking. I'd definitely replace the battery. However ... I don't see how any of this could contribute to it dying at junctions, expecially as the alternator seems to be charging reasonably well so the batery voltage should be quite acceptable under normal driving conditions.