P1621 Trouble Code
Discussion
Hi,
I bought an engine management diagnostic tool for my 1996 XJR. It has found an error code ‘P1621 – ECM Immobiliser Circuit Malfunction; Out of range voltage for diagnostic line’. If I clear the code, it seems to come back after a couple of weeks.
Any hints as to what might cause this would be greatly appreciated.
Cheers,
I bought an engine management diagnostic tool for my 1996 XJR. It has found an error code ‘P1621 – ECM Immobiliser Circuit Malfunction; Out of range voltage for diagnostic line’. If I clear the code, it seems to come back after a couple of weeks.
Any hints as to what might cause this would be greatly appreciated.
Cheers,
Jagtech, I found this out on the Web - don't know if it helps:
My car, I discovered, had a pre-set DTC (trouble code) P1621. I cleared this but still don't understand the cause of the DTC.
I also found this same code set in my friend's XJ6 Executive.
I'm told that this code is a dashboard computer fault. But does anybody know what actually causes it?
The car very occasionally does something strange on unlocking the doors with the key fob. It repeatedly cycles the central unlocking function. Pressing the lock and then unlock on fob stops it cycling but I think this may be setting the P1621 code. Tough one to replicate and prove for sure. It also leaves the question of how the system gets into the loop in the first place. If I find out more I’ll add it later. Thanks again for the pointer.
Source was www.motorcars-ltd.com .........John.
>> Edited by ford prefect on Friday 28th March 10:56
My car, I discovered, had a pre-set DTC (trouble code) P1621. I cleared this but still don't understand the cause of the DTC.
I also found this same code set in my friend's XJ6 Executive.
I'm told that this code is a dashboard computer fault. But does anybody know what actually causes it?
The car very occasionally does something strange on unlocking the doors with the key fob. It repeatedly cycles the central unlocking function. Pressing the lock and then unlock on fob stops it cycling but I think this may be setting the P1621 code. Tough one to replicate and prove for sure. It also leaves the question of how the system gets into the loop in the first place. If I find out more I’ll add it later. Thanks again for the pointer.
Source was www.motorcars-ltd.com .........John.
>> Edited by ford prefect on Friday 28th March 10:56
Thanks Ford Prefect.
It is always nice to know that I am not alone in detecting a strange fault.
I have spoken to a Jaguar Service Engineer since posting my question and it appears that this is a common fault code on X300’s around this age. He believed the fault was caused by low battery voltage (generally if the car is unused for several days). My understanding, following this conversation, is that the service staff just clear the code and do not try to investigate it.
Cheers,
It is always nice to know that I am not alone in detecting a strange fault.
I have spoken to a Jaguar Service Engineer since posting my question and it appears that this is a common fault code on X300’s around this age. He believed the fault was caused by low battery voltage (generally if the car is unused for several days). My understanding, following this conversation, is that the service staff just clear the code and do not try to investigate it.
Cheers,
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