DTC P0C18
- Drive Motor 2 Position Not Learned
Circuit/System Description
The drive motor generator position sensor is monitored by the motor control module (MCM). The MCM monitors the angular position, speed and
direction of the drive motor generator based upon the signals of the resolver-type position sensor. The position sensor, or resolver, contains a drive
coil, two driven coils and an irregular shaped metallic rotor. The metallic rotor is mechanically attached to the shaft of the drive motor generator. At
ignition ON, the MCM outputs a 7 volt ac, 10 kHz excitation signal to the drive coil. The drive coil excitation signal creates a magnetic field
surrounding the two driven coils and the irregular shaped rotor. The MCM then monitors the two driven coil circuits for a return signal. The
position of the irregular shaped metallic rotor causes the magnetically-induced return signals of the driven coils to vary in size and shape. A
comparison of the two driven coil signals allows the MCM to determine the exact position, speed and direction of the drive motor generator.
The position sensor is a non-serviceable part of the drive motor generator assembly.
Offset is the relationship between the position sensor and the drive motor generator output shaft. Whenever the ignition is cycled to OFF, the MCM
attempts to learn the offset of the drive motor position sensor. The MCM will attempt to learn the position at hybrid wake-up (ignition ON) only if
no valid offset value has ever been learned. This condition would normally occur only after an MCM reprogramming event.
Conditions for Running the DTC
Condition 1, 2, 3 and 4
* Hybrid wake-up signal is active.
* The MCM has not previously learned a valid drive motor position sensor offset value.
Condition 2
Motor speed is less than 20 RPM.
Conditions for Setting the DTC
Condition 1
Position sensor offset value not learned because drive motor speed is greater than 50 RPM.
Condition 2
Position sensor offset value not learned because hybrid battery voltage is less than 192V.
Condition 3
Position sensor offset value not learned because drive motor phase to phase current difference is less than 15 A.
Condition 4
Position sensor offset value not learned because offset learn value is greater than 25 degrees.
Action Taken When the DTC Sets
P0C17 and P0C18 are Type B DTCs.
Conditions for Clearing the DTC
P0C17 and P0C18 are Type B DTCs.
Reference Information
Schematic Reference
Hybrid Controls Schematics ()
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Verification
1. Ignition OFF, wait 2 minutes.
2. Ignition ON, wait 2 minutes and then turn ignition OFF.
3. Ignition ON, monitor DTC Status. DTC P0C17 and P0C18 should have passed last test.
