DTC Descriptor
DTC P0C2F
- Control Module Drive Motor Speed - Engine Speed Correlation
Circuit/System Description
The drive motor generator power inverter module (PIM) contains two motor control modules (MCM). Each MCM controls and monitors its
respective drive motor generator based upon commands from the hybrid powertrain control module (HPCM). In order for the HPCM to monitor the
internal combustion engine speed, MCM 1 is electrically connected to the crankshaft position sensor (CKP) signal and reference circuits. The MCM
1 engine speed information is broadcast to the HPCM over an internal PIM communication circuit. Additionally, the HPCM receives a GM LAN
engine speed that is broadcast by the engine control module (ECM) and is based upon the ECM connection to the CKP sensor.
A drive motor generator position sensor is monitored by each motor control module (MCM). Each MCM monitors the angular position, speed and
direction of its respective drive motor generator based upon the signals of the resolver-type position sensor.
The HPCM mathematically calculates what engine speed should be based upon the current transmission ratio and the drive motor generator speeds
indicated by the drive motor generator position sensors.
The HPCM compares this mathematically calculated engine speed to the sensor-derived GM LAN ECM engine speed signal and MCM CKP signal
engine speed. If the drive motor generator position sensor speeds are correct, the mathematical equation should accurately calculate engine speed. If
the mathematical calculation for engine speed does not match the sensor-derived engine speed, a drive motor position speed sensor error is assumed
and this DTC will set.
Conditions for Running the DTC
Condition 1
* The ignition is ON.
* Ignition voltage is greater than 6 volts.
* GM LAN ECM or MCM 1 CKP engine speed is less than 1500 RPM.
Condition 2
* The ignition is ON.
* Ignition voltage is greater than 6 volts.
* GM LAN ECM or MCM 1 CKP engine speed is greater than 1500 RPM.
Conditions for Setting the DTC
Condition 1
The difference between GM LAN ECM or MCM 1 CKP engine speed and HPCM calculated engine speed is greater than 1499 RPM for 1 second.
Condition 2
The difference between GM LAN ECM or MCM 1 CKP engine speed and HPCM calculated engine speed is greater than 249 RPM for 1 second.
Action Taken When the DTC Sets
* DTC P0C2F is a Type A DTC.
* The HPCM commands the battery energy control module (BECM) to open the high voltage contactor relays.
Conditions for Clearing the DTC
* DTC P0C2F is a Type A DTC.
* GM LAN ECM or MCM 1 CKP engine speed is greater than 500 RPM and the difference from HPCM calculated engine speed is less than
151 RPM.
Diagnostic Aids
Any condition that allows the engine or drive motor speed sensors to indicate their actual speed incorrectly may cause this DTC to set.
Reference Information
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (See: Diagnostic Trouble Code Descriptions/Powertrain Diagnostic Trouble Code
(DTC) Type Definitions)
Circuit/System Verification
