ASE A8 Practice Test

Verifying the repair is always the last step in making sure the repair was complete.

Virtually all OEM service information is accessed via the Internet. Technician A is wrong because paper service manuals are currently obsolete.

On almost all data services you must have the make, model and year.

The illustration shows an ST125.

Both technicians are correct.

The test light going off and on indicates that the ignition coil triggering device is working but the failure of a spark indicates a coil failure.

Technician A is correct because all misfires set a Specific DTC and will increase HC and CO. Technician B is wrong because a lean misfire also sets a DTC and will not increase HC and CO.

You need to check for a voltage drop on the injector ground. A voltage drop could indicate unwanted resistance in the ground circuit, which may prevent the injector from operating correctly. Other checks like the power feed and continuity to the ECM are secondary in this situation. The immediate focus should be on checking for a voltage drop in the injector ground to ensure the injector can receive sufficient operational voltage.

If battery power is lost the learned value from the RAM may be lost. RAM data is electronically retained which means that it is always to some extent volatile; that is, data storage could be described as temporary - if the circuit is opened, RAM data is lost. It should be noted that most PCMs use only fully volatile RAM. In other words, when the ignition circuit is opened all RAM data is dumped. A second type of RAM is used in some PCMs. This is non-volatile RAM (NV-RAM) (or KAM-Keep alive memory) in which data is retained until either the battery is disconnected or the PCM is reset, usually by depressing a computer reset button, which temporarily opens the circuit. Codes and failure strategy (action sequence) would be written to NV-RAM and retained until reset.

Technician A is correct because on many engines the PCV provides a portion of the idle air and if it is restricted it creates positive crankcase pressure which will push the engine oil out of the engine. Technician B is wrong because the PCV system should create a slight vacuum in the crankcase at 2500 RPM.

Spark knock is a symptom of an EGR valve that is always closed. The other choices are wrong because they are symptoms of an EGR valve that is always open.

Both technicians are correct.

PCV valve is the exception because it has a very indirect effect on the air/fuel mixture ratio and is not an electronic component.

Technician B is correct because many diagnostic trouble codes (DTC) will monitor items only when the engine control system is in closed loop. Closed loop operation requires the engine to reach a certain operating temperature before it can be entered. Technician A is wrong because the on-board self-diagnostics test mode procedures should be conducted on a warm engine (NOT a COLD engine as stated in the question) that is in closed loop because many DTCs only monitor in closed loop.

On vehicles equipped with OBD II, use of two oxygen sensors is required to monitor catalytic converter efficiency. The front oxygen sensor is located before the catalytic converter (upstream) and the rear oxygen sensor is located after the converter (downstream). During closed loop fuel control, the ECM compares the signals from the two oxygen sensors. One important point to remember is that a rear O2 sensor is used only for diagnostics. It usually has no influence on engine operation or driveability.