P0880

ALLISON AUTOMATIC TRANSMISSION

DTC P0880

DTC P0880 Step 1 - 8:

Circuit Description for Allison Automatic Transmission

Important: DTC P0880 was previously P1760.

DTC P0880 will set if an abnormal power-down sequence has occurred. This condition means the Transmission Control Module (TCM) has lost Battery Positive Voltage Circuit, supply voltage, before it has finished saving information from that drive cycle. This process is usually completed in less than 10 seconds.

DTC P0880 is a type C DTC.

Conditions for Running the DTC
^ The components are powered and ignition voltage is greater than 9 V and less than 18V.
^ Loss of TCM supply voltage before drive cycle data is saved.

Conditions for Setting the DTC
If the TCM loses TCM supply voltage less than 10 seconds after the ignition voltage has been turned off,DTC P0880 will be set during the next ignition cycle.

Action Taken When the DTC Sets
^ DTC P0880 will be stored in the TCM history.
^ Loss of adaptive information for drive cycle. Revert to previous adaptive settings.
^ TCM inhibits TCC engagement.

Conditions for Clearing the MIL/DTC
A scan tool can clear the code from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.

Diagnostic Aids
^ Inspect the wiring for poor electrical connections at the TCM. Look for the following conditions:
- A bent terminal
- A backed-out terminal
- A damaged terminal
- Poor terminal tension
- A chafed wire
- A broken wire inside the insulation
^ When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.
^ You may have to drive the vehicle in order to experience a fault.

Test Description
The numbers refer to the step numbers on the diagnostic table.
2. This step tests the system voltage.
4. This step tests the vehicle charging system.
5. This step tests the wiring harness for opens or shorts.