Maybe someone here has specific info about the communication between the Immobilizer module and the Delco GMPT E15 ecu. The ecu is a non-CAN bus device and in the Speedster/VX220 these communicate to eachother over 1 signal wire. (ECU pin 59)
The OBDII diagnostics plug communicates with 1 signal wire to the immobilizer unit and from there over the above mentioned wire to the E15 ecu. Need more info about the OBDII communication protocol. (My limited computer knowledge tells me that 1 computer pin for serial data transfer can only work with 1 protocol....)
I need this info to find out if an US spec ecu of the LSJ engine communicates in the same language. (The LSJ also has a non-CAN ecu)
If so, it should be possible that the LSJ ecu is capable to re-learn my immobilizer return signal.
(There is a specific procedure to re-learn an immobilizer password on this ecu. Maybe also on the E15 ecu?)
Thxs for any info.
Edit:
Just found that GM uses the J1850 VPW protocol, but I'm not sure about our European cars. It can be the J1850 VPW or ISO9141-2, as both are single wire systems. Anybody??
*Here is a summary of some of the vehicle networks standards...
J1850 VPW (Variable Pulse Width) – this is the 10.4kbps protocol used mainly on GM vehicles. Single wire.
J1850 PWM (Pulse Width Modulated) – this is the 41.6kbps protocol used mainly on Ford vehicles. Dual wire.
ISO9141-2 – This is the 10.4kbps asynchronous protocol used mainly on Chrysler, European, and Asian vehicles. The protocol messages are the J1850 messages but the physical interface is different. The protocol bit format is the same as an asynchronous PC serial port but the unique bit rate and voltages require a converter to be used for PC to vehicle communications. A slow 5bps handshake sequence is require to initialize the ISO interface to start communications. Most vehicles will terminate the communications session if a command is not received for 5 seconds. Single wire.
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