Volt

DTC P0C17 or P0C18

The drive motor position sensor is monitored by the motor control module. The motor control module 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 vehicle ON, the motor control module outputs a 7 V alternating current, 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 motor control module 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 motor control module to determine the exact position, speed and direction of the drive motor generator.

Offset is the relationship between the position sensor and the drive motor generator output shaft. Whenever the vehicle is cycled to OFF, the motor control module attempts to learn the offset of the drive motor position sensor. The motor control module will attempt to learn the position at hybrid wake-up, vehicle ON, only if no valid offset value has ever been learned. The non-learned condition would normally occur only after a motor control module reprogramming event.

Vehicle is cycled from ON to OFF.

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 192 V.

Condition 3

Position sensor offset value not learned because drive motor phase current is less than 15 A.

DTCs P0C17 and P0C18 are Type A DTCs.

DTCs P0C17 and P0C18 are Type A DTCs.

Schematic Reference

Hybrid Controls Schematics

Scan Tool Reference

Control Module References for scan tool information

1. Verify that DTCs P0A40, P0A45, P0A46, P0A78, P0A79, P0A3F, P0C05, P0C08, P0C0B, P0C0E, P0C4E, P0C4F, P0C52, P0C53, P0C57, P0C58, P0C61, P0C62, P0C5C, P0C5D, P1B03, P1B04, P1B0D or P1B0E is not set.

⇒	If DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .

2. If the DTC is set, program the T6 power inverter module. If the DTC resets, replace the T6 power inverter module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Drive Motor Generator Power Inverter Module, also called the power inverter module, replacement, programming and set-up.