Torque Monitor
The torque monitor resides within the TCM as both software and as a redundant safety processor. The torque monitor detects certain computer concerns of the TCM. The torque monitor also detects if the overall powertrain torque delivered to the output shafts of the vehicle is excessive to what the driver is requesting. The torque monitor detects three gross errors that are present for some calibrated amount of time
- unintended vehicle motion - the powertrain accelerates the vehicle when it should not (such as in NEUTRAL) or provides torque in the wrong direction.
- excess acceleration - vehicle accelerates at greater rate than the driver or the cruise control requests.
- excess powertrain deceleration - vehicle powertrain braking exceeds driver demand.
When any of the gross errors are detected, the torque monitor communicates it to the TCM, which initiates appropriate action such as LOS mode. The torque monitor requested LOS mode can be cleared when the concern is no longer present, and the ignition is cycled to the OFF position for about 10 seconds.
Torque Determination and Energy Management
The TCM is responsible for torque determination and energy management functions. The TCM monitors gear selector position (PRNDL), brake pedal position (BPP) and accelerator pedal position (APP). The TCM then makes a torque command determination. Positive torque is perceived as vehicle acceleration and negative torque is perceived as braking. Based on the amount of torque requested by the driver, the TCM decides which power source has to deliver the torque to meet the driver demand while the powertrain system is running most efficiently.
Misfire Monitor Specifications
Misfire monitor operation sets DTCs P0300 to P0304 (general and specific cylinder misfire), P0315 (unable to learn profile), P0316 (misfire during first 1, 000 revolutions after start up). The monitor execution is continuous. The misfire rate is calculated every 200 or 1, 000 revolutions. The monitor does not have a specific sequence. The CKP and CMP11 sensors must operate correctly to run the monitor. The monitoring duration is the entire driving cycle (see disablement conditions below).
Typical misfire monitor entry conditions include entry condition minimum or maximum time since engine start-up is 0 seconds, ECT is -7°C to 121°C (20°F to 250°F), RPM range is (full range misfire certified, with 2 revolutions delay) 2 revolutions after exceeding 150 RPM below drive idle RPM to redline on tach or fuel cutoff. Profile correction factors learned in KAM are Yes, and the fuel tank level is greater than 15%.
Typical misfire temporary disablement conditions include closed throttle deceleration, fuel shut-off due to vehicle speed limiting or engine RPM limiting mode, and a high rate of change of torque (heavy throttle tip-in or tip-out).