OBD II DTCs and Mechanical Engine Problems Explained

What are some of the mechanical engine problems that can cause OBD II DTCs to be set?

Tech A says some mechanical engine problems can cause OBD II DTCs to be set. Tech B says that OBD II codes only monitor non-powertrain components. Who is correct?

Answer:

Neither Tech A nor Tech B is completely correct. Some mechanical engine problems can cause OBD II DTCs, and OBD II codes monitor both powertrain and non-powertrain components.

When it comes to On-Board Diagnostic II (OBD II) Diagnostic Trouble Codes (DTCs), both Tech A and Tech B have partially correct statements. Tech A is correct in stating that some mechanical engine problems can cause these codes to be set. Mechanical engine issues such as misfires, sensor failures, or emissions-related problems can trigger OBD II DTCs.

On the other hand, Tech B is incorrect in stating that OBD II codes only monitor non-powertrain components. In reality, OBD II codes monitor both powertrain and non-powertrain components. The OBD II system is designed to monitor and report malfunctions in various systems, including the engine, transmission, emissions, and other related components.