Exam 19: On Board Diagnostics

The ________ data that the ECM (engine control module) stores will provide a snapshot of the engine operating conditions at the moment when the DTC (diagnostic trouble code) was confirmed by the OBD system.

How many wires will transmit and receive signal data for the CAN engine/powertrain network on the diagnostic datalink connector (DLC) for an OBD-II compliant vehicle?

Technician A says that if all the sensors and components of the aftertreatment system are removed, the OBD-II system will not be able to detect faults in the absence of electrical signals. Technician B says that the comprehensive component monitor (CCM) will set emission-related fault codes. Who is correct?

Technician A says that the OBD system on a diesel is continuously judging all major emissions systems for faults. Technician B says that some emissions monitors do not run every drive cycle and take time to correctly judge emissions system operation. Who is correct?

An enhanced OBD-II code will be indicated by which position in the SAE code structure?

If a coolant temperature sensor shorted to ground, which emissions system monitor would first detect the fault?

Which of the following is a set of prescribed driving cycles performed on a chassis dynamometer which should not to be confused with emissions limits?

Which of the following sense proper thermostat functioning?

Technician A says that some emission-related DTCs will cause engine power derate to encourage a driver to have the emissions system repaired. Technician B says that most diesel engine OBD DTCs will derate engine power. Who is correct?

The threshold for diesel engine misfire detection is ____ per 1,000 crankshaft revolutions.

The CAN module messages are transmitted over a pair of wires called a:

Leaving the filler cap off a diesel fuel tank is an indication of:

Technician A says that in North America, only the EPA (Environmental Protection Agency) outlines standards for OBD (on-board diagnostic) system operation for vehicles operated over the road. Technician B says that the European On-Board Diagnostics (EOBD) and OBD legislation and regulations should not be confused with enhanced OBD codes, which refer to manufacturer-specific or proprietary diagnostic codes. Who is right?

Technician A says that the comprehensive component monitor measures circuit voltage. Technician B says that the comprehensive component monitor gets its name from the vast number of circuits in it. Who is right?

Technician A says that it's important to study engine data during a road test to diagnose MPC (model predictive control) corrections, which diminish power output and increase fuel consumption. Technician B says that you compare data values with other vehicles in known good condition to identify the discrepancy and diagnose which component or system may be changing the MPC of virtual lookup tables. Who is right?

Technician A says that anytime the tailpipe NOx sensor reads more than a few parts per million of NOx, DTCs will switch the MIL on. Technician B says that model predictive control (MPC) will always make adjustments to the engine to correct the fault. Who is correct?

Two technicians are describing exhaust gas recirculation monitor operation. Technician A says that the efficiency of the cooler is monitored by comparing exhaust gas temperature entering and leaving the cooler. Technician B says that the components of the EGR system and associated circuits are evaluated by the monitor after EGR flow is evaluated. Who is right?

The preliminary standard developed by CARB and used before OBD-II was called _____________.

Which of the following is the latest network communication protocol, which has an international standard described in ISO 14229-1:

While two technicians are examining the many pairs of wires connected to an OBD-II DLC, Technician A says that all the wires are needed to retrieve fault does from the OBD system. Technician B says that only a pair of CAN wires are necessary to retrieve OBD-II fault codes. Who is correct?