A vehicle is exhibiting a no crank, no start condition. If the throttle body reveals fuel pouring from the TBI injector when cranking, which technician's diagnosis is correct?

The situation described involves a vehicle that shows a no crank, no start condition, yet fuel is visibly pouring from the throttle body injector when attempting to crank the engine. This clearly indicates an issue with fuel delivery, specifically relating to the fuel injectors.

The correct diagnosis centers on the role of the Powertrain Control Module (PCM) and how it manages fuel injection through electronic control. If Technician B suggests that a shorted PCM driver is causing the injector to be continuously activated, this aligns with the observation of fuel pouring from the injector. In a functioning system, the injectors should only dispense fuel when commanded by the PCM during the cranking and running phases. If the PCM driver is shorted, it would lead to the injector being in an on position continuously, resulting in the excessive fuel observed.

Technician A's diagnosis of the fuel injector being stuck open might lead to a similar symptom; however, the key distinction here is the relationship between the PCM and the injector control. If the PCM driver is shorted, it directly correlates to the uncontrolled flow of fuel, making Technician B's assessment the more precise diagnosis of the situation presented.