A properly terminated high-speed CAN network has two 120-ohm resistors in parallel at the extreme ends of the bus. Parallel resistance: 120Ω || 120Ω = 60Ω. If you measure 120 ohms at the DLC, that means only one terminating resistor is present. The missing resistor is likely inside the TCM or near it, causing signal reflections and intermittent loss of communication. This is a classic CES troubleshooting scenario.
On a high-speed CAN bus (500 kbps), the normal recessive voltage is approximately 2.5V on each line (with a slight variance). 2.6V and 2.4V are within tolerance. These are the bias voltages supplied by terminating resistors. The exam expects you to know that the bus must have ~60 ohms between pins 6 and 14 when the network is asleep, but voltage measurements with key on indicate proper biasing. Lack of communication could be a bad ECM or a broken wire, but the voltages indicate the bus itself is not shorted. ces test questions and answers for engine management
By mastering the outlined above, you will dramatically increase your chances of passing. Remember, the exam isn’t just about remembering codes—it’s about understanding the system’s physics and logic. Good luck on your certification journey! A properly terminated high-speed CAN network has two
The Crew Evaluation System (CES) is here to help assess the background knowledge of seafarers. CES tests for the position Ch-Eng / 2nd-Eng The missing resistor is likely inside the TCM
A) The ignition coil primary winding is shorted. B) The ignition driver (transistor) inside the ECM is shorted to ground. C) The secondary winding is open. D) The spark plug gap is too small.
Explanation: Uniflow scavenging (where air enters at the bottom and exits at the top via exhaust valves) is the standard for modern large bore engines. It provides superior scavenging efficiency, reduces the risk of hot spots on the liner, and improves overall thermal efficiency.
A) Replace spark plug cylinder 2 B) Replace fuel injector cylinder 2 C) Replace ignition coil cylinder 2 D) Perform compression test cylinder 2