L1 Advanced Engine Performance Tests

ASE L1 Test Preparation

Main Wiring Diagram Links:

Diagram 1 of 3 (large post view)
Diagram 2 of 3 (large post view)
Diagram 3 of 3 (large post view)
Diagram 1 of 3 (quick view)
Diagram 2 of 3 (quick view)
Diagram 3 of 3 (quick view)

Composite Vehicle Reference Images:

Vehicle Engine Diagram #1 (large post view)
Vehicle Engine Diagram #2 (large post view)
Composite Vehicle Engine Diagram #1 (quick view)
Composite Vehicle Engine Diagram #2 (quick view)

Composite Vehicle Reference Content

L1 Advanced Engine Performance Part 2

Progress:

1. The composite vehicle fails an I/M 240 test due to high carbon monoxide emissions. HC is barely within limits, while NOx is well below the maximum cut-point. Once the cause of the high CO has been corrected, the vehicle is retested and fails again, only this time for excessive NOx. What is the MOST likely reason for the subsequent failure?

Injector Balance Test 2. The readings shown above were recorded during an injector balance test. All of the following symptoms are relevant with the test results EXCEPT:

3. The Immobilizer Module on the composite vehicle will do all of the following EXCEPT:

4. There is a P0420 "low catalyst efficiency" diagnostic trouble code stored in the memory on a vehicle with a MIL light illuminated. Technician A says that leaking exhaust system may have triggered the problem. Technician B says that the root cause of the problem may be worn valve guide seals. Who is correct?

Emissions Test Results Example 5. According to the test results, which of the following conditions caused the vehicle with a continuous return injection to fail the low-speed portion of a two-speed idle test?

6. The ignition coils on the composite vehicle are being tested with an ohmmeter. Which of these are within specification for the secondary winding?

7. Cylinder number 4 is misfiring on the composite vehicle. All of the following could be the cause EXCEPT:

8. The composite vehicle has an illuminated MIL and has stored a DTC for EVAP system failure. Which of the following could be the cause?

9. The ISC motor toggles back and forth at closed throttle on an overhead valve V8 with DI ignition. A permanent magnet sensor inside distributor is used to generate RPM signal. Technician A says that the problem may be the result of a worn distributor shaft gear. Technician B says that a loose timing chain could be the cause of the problem. Who is correct?

10. The composite vehicle will not shift past second gear. The resistance of both shift solenoids is 24 Ohms. Technician A says that the shift solenoids are defective. Technician B says there could be an open circuit to pin 74 of the TCM. Who is correct?

11. All of the following will disable the A/C compressor clutch on the composite vehicle EXCEPT:

Scanner PID Examples 12. The composite vehicle has an unstable idle, the MIL is on and a DTC P0300 "random cylinder misfire" is stored. According to the scan data shown which of the following could be the root cause of the problem?

13. The composite vehicle failed an I/M 240 test for excessive NOx. Which of the following conditions could be causing the problems?

14. The composite vehicle has high mileage and a low power complaint. The MAP sensor reads 1.76 volts at idle and at a steady 2000 rpm. Technician A says a compression test should be done to check engine condition. Technician B says the engine should be checked for a vacuum leak. Who is correct?

Crankshaft Sensor Waveform Example 15. The CKP (crankshaft position sensor) waveform above was taken from composite vehicle while cranking. Which of the following best describe the waveform?

16. All of the following conditions must be met for the composite vehicle to enter closed loop EXCEPT:

17. A vehicle fails an I/M 240 test for excessive NOx emissions. Technician A says that the engine may have excessive intake valve deposits. Technician B says that a restricted air filter may be causing the problem. Who is correct?

18. The composite vehicle has no fuel pressure. Technician A says that the problem could be a poor connection at ECM terminal 5. Techni­cian B says that the problem could be the result of a blown No. 3 fuse. Who is correct?

19. Refer to the wiring diagram to anwser this question: (click image for larger view) Technician A says that to check the voltage drop in the O2 ground circuit, the voltmeter leads should be connected between PCM terminals B15 and GND101. Technician B says that to check the voltage drop across the main relay switch contacts, the voltmeter leads should be connected between terminals B and D with the relay energized. Who is correct?

20. The composite vehicle fails a loaded mode I/M test for excessive hydrocarbons. which of the following is the root cause of the problem?

21. Once a zirconia oxygen sensor reaches operating temperature, how quickly should it respond to changes in the air/fuel ratio?

Oxygen Sensor Waveform Example 22. The waveform above was captured in closed loop at 1500rpm from the bank 1 oxygen sensor on the composite vehicle. What can be determined by an analysis of the waveform?

23. A cylinder leakage test is being performed on a overhead valve V8 engine. When air is supplied to the number 4 cylinder a hissing noise is heard from the tailpipe. Technician A says the cam lobe for the #4 exhaust valve could be worn down. Technician B says that the #4 exhaust valve could be burned. Who is correct?

24. All of the cylinders in an overhead cam engine have low compression. What is the MOST likely cause of this condition?

25. The usual number of terminating resistors on a CAN harness is:

Click submit and your anwsers and results will be emailed to you, Good Luck!!!

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