ECU immoblizer issue
10-15-2023 | 08:16 AM
#1
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ECU immoblizer issue
I have a 2007 GL500 AU model. My ECU had an issue reading O2 sensor data and I've sources some ECU units from China.
I first bought a brand new 'copycat' ECU, reprogrammed to my car vin number. It throw some alternator issue sometimes yet drives fine otherwise. After 2 weeks, it developed an issue that sometimes it can't start the engine. Basically everything else powers on but no cranking at all, and scanner shows no codes.
Then I sourced another used ECU from wrecks and reprogrammed as well. Now there's no alternator error and the car drives perfectly fine. However, again, after couple weeks, yesterday, I had the same engine no cranking issue. Swapped and tested both keys are with same problem. 2 hours later, both keys start the engine without any issues. Today, there's no issue.
I'm wondering, anyone knows, how immobilizer works? Keys are programed to my VIN and the ECU is also programmed to VIN?
Thanks in advance.
I first bought a brand new 'copycat' ECU, reprogrammed to my car vin number. It throw some alternator issue sometimes yet drives fine otherwise. After 2 weeks, it developed an issue that sometimes it can't start the engine. Basically everything else powers on but no cranking at all, and scanner shows no codes.
Then I sourced another used ECU from wrecks and reprogrammed as well. Now there's no alternator error and the car drives perfectly fine. However, again, after couple weeks, yesterday, I had the same engine no cranking issue. Swapped and tested both keys are with same problem. 2 hours later, both keys start the engine without any issues. Today, there's no issue.
I'm wondering, anyone knows, how immobilizer works? Keys are programed to my VIN and the ECU is also programmed to VIN?
Thanks in advance.
10-16-2023 | 07:34 AM
#3
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Joined: Apr 2017
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cls
I have an Autel mx808 scanner which can do some ‘system learning'. I mean I just plug the new ecu and have it 'learn' 'driving permission' (sorry my autel is a Chinese version which doesn't have english menu). Then I can start/drive the car with the new ECU.
10-16-2023 | 12:30 PM
#4
MBWorld Fanatic!
Joined: Jun 2010
Posts: 2,657
Likes: 594
From: Emmett, ID, USA
2007 GL450
There is a huge list of vehicle variations that are coded at the factory, like what region, engine type, and so forth.
When I replaced the ECU on my GL, the shop desoldered the EEPROM, which I believe contains both the Immobilizer and variant coding, and read it, dumping the contents into the replacement ECU. Or they just soldered the old EEPROM onto the new ECU.
I am thinking it has to be in the variant coding because it seems to me the immobilizer would do just that: immobilize. Not work for two weeks and then stop. However, I know there are features on the diesel motors that only allow a certain number of start cycles.
Your Autel should have a variant coding transfer function. My MP808 does. You also could simply photograph the screens, but there are something like a hundred entries.
When I replaced the ECU on my GL, the shop desoldered the EEPROM, which I believe contains both the Immobilizer and variant coding, and read it, dumping the contents into the replacement ECU. Or they just soldered the old EEPROM onto the new ECU.
I am thinking it has to be in the variant coding because it seems to me the immobilizer would do just that: immobilize. Not work for two weeks and then stop. However, I know there are features on the diesel motors that only allow a certain number of start cycles.
Your Autel should have a variant coding transfer function. My MP808 does. You also could simply photograph the screens, but there are something like a hundred entries.
