Ecm not communicating after repair

2003 ISUZU RODEO

128,000 MILES • V6 • 2WD • AUTOMATIC

EMBERLY DIONNE

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Hello!
First of all thanks for looking at my question. I have been trying to get my car fixed for almost two months to no avail.
We assumed had a bad ECM after the key couldn’t be reprogrammed to the car. It was sent off and rebuilt (took almost a month) when I finally brought it back to the repair shop they said that they had the guy come out and he redid the key, but the car still will not start.
ECM is rebuilt and is now communicating enough to reprogram the key, (which is how they knew it was bad in the first place). But it is not communicating with the computer.
He said it could be the BCM but even if they replaced that he says the software for a 2003 Rodeo is no longer made.
Can this be right? My car is only fifteen years old. I realize Isuzu went out of business but there has to be a way to get software for older cars. Should I have the car towed to a more knowledgeable place?
Any help would be a God send.
Thanks again for reading.

Dec 17, 2018 at 10:58 PM

ASEMASTER6371

CERTIFIED EXPERT
52,796 POSTS

Good afternoon.

First, the tech information is not accurate about the BCM. the old BCM information can be downloaded and installed in the replacement BCM.

The BCM does not have any involvement in the key issue. below is the description of the system.

You need to take this to a shop that can accurately diagnose your issue and not guess like the shop you have it at now.

Below is the wiring diagram for the system. They need a scan tool to check this system the correct way?

Roy

Circuit Operation
Immobilizer control unit (ICU) permits engine starting, when the security code which compares the security code registered into the transponder (key) and the security code registered into ICU, and is similarly registered into ICU and engine control unit (ECM) is compared and it is judged that it is normal. When the code registered into the key is unusual, and when not recognizing a security code, ICU does not permit starting of engine.

Image (Click to enlarge)

Dec 19, 2018 at 12:42 PM