When the crankshaft position sensor (POS) signal is not detected by the ECM during the first few seconds of engine cranking, the ECM (engine control module) will set a code P0335. A bad (Crankshaft Position Sensor [CKP]) ground will cause the engine not to start and set this code.

On the typical NO-Start Symptom Flow Chart, the "Ignition Circuit" is listed as a priority 1 item in the order of inspection to check first. The other answers in this question could be the root cause and should be part of a sequenced diagnostic process.

It is MOST likely that on the first trip a misfire condition can occur that can damage the three way catalyst (TWC) due to overheating. Specific on board diagnostic items will cause the ECM to light up or blink the MIL, and store DTC and Freeze Frame data, even in the 1st trip; e.g., Misfire (Possible three way catalyst damage) -- DTC: P0300 -P0306 will MOST likely set.

Both technicians are correct. Technician A is right because before any reprogramming takes place you must determine what software is needed and installed. Technician B is right because reprogramming is proprietary and generally requires the factory scan tool or current software with a laptop computer and adapter.

Technician B is right because as the computer pulses the coil on and off the voltage reading will fluctuate. Technician A is wrong because you check for voltage at the positive terminal not the negative terminal.

The running vacuum test will show a weak or broken valve spring. Weak valve springs will produce a normal reading at idle, but as engine speed increases, the needle will fluctuate rapidly between 12 and 24 inches of Mercury. The other choices will not show a broken valve spring.

The running vacuum test will show a weak or broken valve spring. Weak valve springs will produce a normal reading at idle, but as engine speed increases, the needle will fluctuate rapidly between 12 and 24 inches of Mercury. The other choices will not show a broken valve spring.

Technician A is right 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.

Both technicians are right because DTC (Diagnostic Trouble Code) P0456 (small leak detected in EVAP canister system) is caused by the following: defective vent or purge solenoid, leak in the EVAP hoses or a defective, loose or wrong gas cap.

A 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.

The loaded mode test and the Acceleration Simulation Mode (ASM) requires the use of a dynamometer to place a single weight load on the vehicle, which simulates actual driving similar to the Federal test used to certify vehicles by the EPA.

Clogged air filter is right because the CO (Carbon Monoxide) reading is high at both 600 and 2000 RPM where at those RPM values it should have been less than 0.5% and it also increased with high RPM suggesting air starvation. HC (Hydrocarbons) is higher at 2000 RPM showing excess fuel in the system. The other readings are normal. B is wrong because a defective spark plug would have caused higher HC readings. C is wrong because a defective EGR valve would have affected NOx readings, which are normal. D is wrong because a clogged fuel filter would not show high CO.