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What year is your car?
If it is an UK car then I think these came with some kind of aftermarket alarm system known to cause troubles, might be worth checking.
Hey Flanders, It's definitely a UK car, there is no green key light coming on the dash when I insert the key and turn it, I am yet to conclude if this is highlighting the issue, what I do know is I've replaced the immobiliser and its not helped the issue
Since the above is posted from the Service Manual may we assume you've looked at the Immobilizer section starting at p. 22-192? (Yeah, I'm losing track of the details in this thread. )
Fuse 25 seems to control the immobilizer including the indicator light.
-- Chuck
Thanks for the continued support Chuck, We can rule that out, the fuse is fine!
Ok found it was 2002 car.
There's a few interesting pins on ecu connector A that you can check for voltage, thinking mainly on 12 and 15.
Check picture bellow.
After that I would check fuel pump circuit, main relay is not that uncommon to go bad and would explain if fuel pump is not priming.
Hey Flanders, It's definitely a UK car, there is no green key light coming on the dash when I insert the key and turn it, I am yet to conclude if this is highlighting the issue, what I do know is I've replaced the immobiliser and its not helped the issue
you replaced the immobilizer ANTENNA.
find whatever aftermarket UK thing is there(assuming it is) and delete it.
check for voltage at the PGMFI Main relay IN and OUT.
Hey everyone, I'm back, sadly been away for nearly a month, car still sat on drive I've got to find the problem, so would be super grateful for continued help, the last two replies are below and Im a bit confused, so if thats ok, could you help me understand?
Originally Posted by spider2k
find whatever aftermarket UK thing is there(assuming it is) and delete it.
check for voltage at the PGMFI Main relay IN and OUT.
Hi Spider, I'm not sure what you mean by UK aftermarket thing, could that be the Thatcham alarm? How would you delete that, maybe I am confused here?
Also, where is the PGMFI, sorry for the stupid question
Originally Posted by flanders
Ok found it was 2002 car.
There's a few interesting pins on ecu connector A that you can check for voltage, thinking mainly on 12 and 15.
Check picture bellow.
After that I would check fuel pump circuit, main relay is not that uncommon to go bad and would explain if fuel pump is not priming.
Flanders, thanks, this seems logical to check, as its quite possible its an electrical fault Im trying to find, however, where is this ECU connector? When I know where it is, do you suggest, unplugging it, turning car ignition to ON and then testing with multimeter?
Lastly, the last point you made about checking the fuel pump circuit, which bit exactly do you recommend checking?
I apologise to you all for the dumb questions, Im not completely useless, hence can troubleshoot and have an ok understanding of electronics, but not sure where Im meant to be testing here from the diagram you posted?
> Hi Spider, I'm not sure what you mean by UK aftermarket thing, could that be the Thatcham alarm? How would you delete that, maybe I am confused here?
He means to remove all of the splicing/wiring connected to the Thatcham alarm.
Electronic diagnostics in cars are detailed step by step in the service manual--but I'll give a quick summary of what it generally tries to do:
1. Check for continuity between ground. This is easy to do. Set your multimeter to continuity (or resistance if it is not present on your tool), and make sure that it shares continuity/low resistance number between the Ground wire and any unpainted surface.
2. Check for continuity between each pin. This one is more challenging, so you might need a longer probe, but essentially it is: remove the connector (or use a backprobe), insert one end into the corresponding pin (pin 1 or something), and then insert the other end where pin 1 is labeled as in the wiring diagram.
This lets you know if the wires are the issue here.
From there, you can start checking voltages. This varies from component to component, so please refer to the service manual.
The ECU is located on the drivers side. Google it for more information/diagram/videos. ECM connector A should be 31-GRY (Number of holes - Color), ECM connector B is 24-WHT.
He means to remove all of the splicing/wiring connected to the Thatcham alarm.
Hey thanks very much bad driver would that disable it then? I've seen some stuff on youtube where they look to be breaking off some kind of chip inside the immobiliser to completely disable it, not sure if its a thatcham, possibly different model, but watching a guy break off a big electronic board/chip seemed pretty drastic move, I'm not sure I am comfortable doing that?
I genuinely have no context on the Thatcher alarm system and it would be disingenuous for me to advise you any further.
The United States models do not have such an aftermarket system fitted and have all of the immobilizer tech on the ECM/receiver side. I assume yours is likely compromised somewhere in the signal chain with the Thatcher system.
The stuff you are saying is legitimately concerning, I have never heard of breaking a chip off of an immobilizer to remove an aftermarket alarm system.
Even more annoyingly, I can't seem to find a wiring diagram for the Thatcher. I would do some investigation to see if you could find the actual Thatcher unit itself. I'd start from the ECU side, investigating the connectors, until you find a mysterious device that is connected to it that is not mentioned in the service manual.
If you are still struggling with finding the Thatcher unit itself and investigating the wires there, it might be time to call it quits and call in a specialist.
Flanders, thanks, this seems logical to check, as its quite possible its an electrical fault Im trying to find, however, where is this ECU connector? When I know where it is, do you suggest, unplugging it, turning car ignition to ON and then testing with multimeter?
Lastly, the last point you made about checking the fuel pump circuit, which bit exactly do you recommend checking?
I apologise to you all for the dumb questions, Im not completely useless, hence can troubleshoot and have an ok understanding of electronics, but not sure where Im meant to be testing here from the diagram you posted?
You should not need to unplug anything, just measure from the back side of the connector.
Going to need really small probes on your multimeter, or just a piece of wire between connector and probe.
If you look at the circuit diagram I posted you can see ecu A15 drives the coil on the main relay which closes the contact on pin4 that supplies power to fuel pump.
As for locations on ecu, main relay etc try searching in UK section as the placement will be different than on LHD cars that I'm familiar with.
02-20-2024, 07:36 AM
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I've got to find the problem, so would be super grateful for continued help, the last two replies are below and Im a bit confused, so if thats ok, could you help me understand?
