Sometimes when working with immobilizer EEPROMs, the ideal way of programming the EEPROM is by doing it while it is in the circuit, as removing it, programming and resoldering it back to the circuit, adds a bit more of effort to complete the job.
Doing it “in-circuit” can be accomplished by using the SOIC-8 clip, connecting it over the EEPROM chip while it is in circuit, but sometimes, some inconveniences are present. Some of those inconveniences are; the need of cleaning the EEPROM leads from any protecting coating the ECM might have, or the fact that the EEPROM in question might have a too low profile, making it impossible to keep the clip in place, or the situation that we will cover here; the ECM circuit is too sensitive to the voltage that the EEPROM programmer injects to it, for working (reading/writing) with the EEPROM. In this case, the problem is that the micro controller of the ECM is attempting to start (run) with the reading supplied voltage. Of course, thus will vary from ECM to ECM and from programmer to programmer.
The solution for this situation is Read the rest of this entry