CIRCUIT DESCRIPTION:The TCM requires a switched ignition voltage input to operate. This switched ignition voltage signal originates from the ignition switch or an ignition relay to supply voltage to wire 163 in the 80-way connector at the TCM. DTC P0563 sets when the TCM detects high ignition voltage by comparing to a calibrated value for calibrated number of samples. This DTC is only enabled with GM L96 applications. ACTION TAKEN WHEN THE DTC SETS:1. The TCM does not illuminate the CHECK TRANS light.2. The TCM forces Variable Modulated Main off.3. The TCM freezes shift adapts (DNA).4. The TCM inhibits Torque...

CIRCUIT DESCRIPTION:At the power up and after clearing DTCs, the TCM performs a self-test to determine if the calibration in memory is valid. ACTION TAKEN WHEN THE DTC SETS:1. DTC P0602 is stored in the TCM history.2. The TCM does not illuminate the CHECK TRANS light (non-OBD II strategy).3. The TCM returns to the boot program, and then waits to be recalibrated.4. Transmission operates in hydraulic default, Reverse, Neutral, and 3rd ranges.5. DTC is stored in the TCM history. CONDITIONS FOR CLEARING THE DTC:TCM must be recalibrated with a valid VEPS calibration. Allison 1000 & 2000 Gen 5 Fault Code:P0563...

CIRCUIT DESCRIPTION:The Transmission Control Module (TCM) performs an internal memory self-test at power up that tests Flash Memory. ACTION TAKEN WHEN THE DTC SETS:1. The CHECK TRANS light illuminates.2. Hydraulic Default. The transmission is restricted to Reverse, Neutral, and 3rd range. CONDITIONS FOR CLEARING THE DTC:Replace TCM. DIAGNOSTIC AIDS:Replace TCM. Allison 1000 & 2000 Gen 5 Fault Code:P0602 TCM Not Programmed Allison 1000 & 2000 Gen 5 Fault Code:P0563 System Voltage – High Allison 1000 & 2000 Gen 5 Fault Code:P0562 System Voltage – Low Allison 1000 & 2000 Gen 5 Fault Code:P0561 System Voltage – Performance Allison 1000 &...

CIRCUIT DESCRIPTION:The Transmission Control Module (TCM) performs an internal memory self-test at power up that writes and reads patterns at specific RAM locations to verify that all addresses and data lines are functioning correctly. ACTION TAKEN WHEN THE DTC SETS:1. The CHECK TRANS light illuminates.2. DTC is stored in the TCM history on next key cycle.3. The TCM returns to the boot program.4. The TCM inhibits shifts to range. CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHTReplace TCM. DIAGNOSTIC AIDS:Replace TCM. Allison 1000 & 2000 Gen 5 Fault Code:P0603 Internal Control Module Keep Alive Memory Error Allison 1000 & 2000 Gen...

CIRCUIT DESCRIPTION:The TCM is equipped with an internal accelerometer used for Load Based Shift Scheduling (LBSS) and a variety of other purposes. This diagnostic test reports when the accelerometer is malfunctioning. ACTION TAKEN WHEN THE DTC SETS:1. The TCM does not illuminate the CHECK TRANS light.2. DTC is stored in TCM history.3. LBSS estimates are calculated based on other transmission parameters besides accelerometer data. CONDITIONS FOR CLEARING THE DTC:Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes forty warm-up cycles without the DTC...