A vehicle's engine computer does not operate properly. The vehicle's battery is checked with a DVOM and has an open circuit voltage of 8.3 volts.
Technician A says that the PCM is probably defective and should be replaced. Technician B says that, before condemning the PCM, the battery should be charged and retested. Then the appropriate voltage drop tests of the PCM's power and ground circuits should be performed. Who is correct?
A) Technician A only
B) Technician B only
C) Both technicians
D) Neither technician

Question

A vehicle's engine computer does not operate properly.  The vehicle's battery is checked with a DVOM and has an open circuit voltage of 8.3 volts.
Technician A says that the PCM is probably defective and should be replaced. Technician B says that, before condemning the PCM, the battery should be charged and retested.  Then the appropriate voltage drop tests of the PCM's power and ground circuits should be performed. Who is correct?
A) Technician A only
B) Technician B only
C) Both technicians
D) Neither technician

Quizplus · Accepted Answer

Technician B is correct because the battery voltage is significantly lower than the normal 12.6 volts for a fully charged battery. This low voltage could prevent the PCM (Powertrain Control Module) from operating correctly. The battery should be charged and tested before any components are replaced. Performing voltage drop tests on the PCM's power and ground circuits after ensuring the battery is in good condition is a logical diagnostic step.

A Vehicle's Engine Computer Does Not Operate Properly