Transaxle Comprehensive Component Monitor (CCM)

TRANSAXLE COMPREHENSIVE COMPONENT MONITOR (CCM)

The transaxle CCM monitors for concerns in the transaxle system. The transaxle CCM monitors internal and external electronic and mechanical components, as well as internal and external circuits which provide input or output signals to or from the transaxle control module (TCM). The circuitry and components are typically monitored for circuit continuity and correct range of values. Where feasible, they are also checked for rationality.

The transaxle CCM covers many components and circuits and tests them in various ways depending on the hardware, function, and type of signal. For example, input and output signals are typically checked for opens, shorts, and in-range failures. This type of monitoring is carried out continuously. Some TCM input and output signals may rely on rationality checks - checking to see if the input or output value makes sense for the current system operating conditions. These types of tests may require monitoring several components and can only be carried out under appropriate test conditions.

The following components and circuitry are monitored by the transaxle CCM. The list includes the components or other TCM inputs, corresponding circuitry, and the type of electrical test carried out.

Transaxle fluid temperature sensor and circuit:
- open circuit test
- short circuit to ground test
- short circuit to power test
- in-range failure test

Motor and generator coil temperature sensors and circuits:
- open circuit test
- short circuit to ground test
- short circuit to power test
- in-range failure test

Motor and generator inverter temperature sensors and circuits:
- open circuit test
- short circuit to ground test
- short circuit to power test
- in-range failure test

Motor and generator current sensors and circuits:
- open circuit test
- short circuit to ground test
- short circuit to power test
- in-range failure test
- rationality test

Immediate shutdown 1 and 2 circuits:
- open circuit test
- short circuit to ground test
- rationality test

Generator motor shutdown circuits:
- open circuit test
- short circuit to ground test
- short circuit to power test
- rationality test

Clean tachometer output circuit:
- open circuit test
- short circuit to ground test
- short circuit to power test
- rationality test

Motor and generator inverters:
- open circuit test
- short circuit to ground test
- short circuit to power test
- in-range failure test
- rationality test
- over voltage test

High voltage interlock circuit:
- open circuit test

In addition to the electrical checks, the transaxle CCM also monitors the ignition voltage to the TCM for over voltage and under voltage conditions, traction motor and generator over-speed conditions, park pawl for mechanical damage, and an abnormal shutdown condition. The controller area network (CAN) messages such as revolutions per mile, generator mode, vehicle mode, total torque desired, engine speed desired, and estimated engine torque are monitored for out of range or missing status.

When any monitored component fails and no longer operates within manufacturer's specifications, the TCM stores the diagnostic trouble code (DTC) and illuminates the powertrain malfunction indicator (wrench) lamp or hazard lamp. When the initial concern is detected, the TCM stores the temporary DTC and records the freeze frame data. This temporary DTC is erased on the third vehicle restart after two consecutive detection trips with no concern. However, if the concern is still present after two consecutive detection trips, the powertrain malfunction indicator (wrench) lamp or hazard lamp may be illuminated. Once the powertrain malfunction indicator (wrench) lamp or hazard lamp is illuminated, three consecutive detection trips without a concern are required to extinguish them. Forty warm-up cycles without a concern are required to erase the DTC from the TCM memory.

In addition to the DTC stored, the TCM stores freeze frame data in the electrically erasable programmable read only memory (EEPROM). The following parameters are recorded when freeze frame data is stored:
- DTC item number
- engine speed
- transaxle fluid temperature
- traction motor and generator speed
- highest traction motor and generator inverter temperature
- traction motor and generator coil temperature
- desired total torque
- desired traction motor and generator torque
- shift position

The freeze frame data is accessible with the scan tool to assist in diagnosing the vehicle.