Exam 11: Electronically Controlled Transmission

Technician A says the Powertrain Control Module (PCM) can reduce transmission wear by increasing torque during gear shifting. Technician B says the PCM monitors input shaft and output shaft speed as a method of fault detection. Who is correct?

Some vehicle manufacturers specifically say not to clean the MAF sensors on their vehicles and to instead replace them if they are not reading correctly.

Which of the following is a pressure transducer?

On a completely cooled vehicle, the TFT sensor reading on a scan tool should be very similar to the coolant and ambient air temperature sensor.

Which of the following provides input shaft speed data to the Powertrain Control Module (PCM)?

If the transmission oil is hot, the Powertrain Control Module (PCM) may decrease line pressure to compensate for internal leaks, as thinner oil flows past valves and seals more easily.

Tech A says that reed switches produce air-conditioning voltage. Tech B says that a magnetic VSS can be troubleshot by checking to see if the sensor is producing a DC voltage when the output shaft is turning. Who is correct?

MAP sensors may be used to test if certain emissions-related components are functioning properly, as some emissions components will cause changes in manifold pressure as they operate.

Data from the input shaft speed sensor and output shaft speed sensor are compared by the transmission control module (TCM) or powertrain control module (PCM) to determine all of the following, EXCEPT:

Technician A says a pulse-width modulation of 50% means the valve is energized 50% of the time and de-energized 50% of the time. Technician B says if an EPC pulse-width modulation value is 25%, that means that line pressure is increased by 25%. Who is correct?

Technician A says that any air leaking after the MAF will cause an inaccurate reading that may cause a transmission to have early shifting and driveability problems. Technician B says that any dirt on the MAF will not cause an early shifting problem and driveability problems. Who is correct?

Technician A says that magnetic pickup sensors must be installed in the vehicle to be tested. Technician B says that magnetic pickup sensors do not need to be installed in the vehicle to be tested. Who is correct?

The Powertrain Control Module (PCM) performs basic circuit checks as part of the electronically controlled transmissions self-diagnostic routine. Which of the following would qualify as a basic check?

Which of the following statements is True about the location of Mass Air Flow (MAF) sensors?

When the Powertrain Control Module (PCM) receives the brake switch input, what does the PCM do with the Torque Converter Clutch (TCC)?

Most torque converter clutches are pulsed slowly to avoid a harsh engagement.

Technician A says the Powertrain Control Module (PCM) is able to reduce the amount of torque being produced by the engine right before the transmission shifts. Technician B says limp-in mode refers to the vehicle shutting down in the event of a transmission damaging fault. Who is correct?

Newer PCMs have logic programmed into them that allows more sophisticated self-diagnosis.

Throttle Position Sensors (TPS) typically return around 0.5V when the throttle is closed, and approximately 4.5V when the throttle is wide open.

Technician A says that a TPS signal is an important input used by the PCM to determine transmission operation. Technician B says that scan tool data is the best way to verify TPS operation. Who is correct?