P0780

Shift (1 of 2):

Shift (2 of 2):

Circuit Description:

The Powertrain Control Module (PCM) monitors throttle opening, engine speed, vehicle speed and gear position. The PCM uses engine speed and vehicle speed to calculate input/output ratio and compares it with pre-determined values. If actual ratio does not match values stored in the PCM, a shift malfunction exists.

DTC Detecting Condition:

DTC P078O will set if the following condition is met: Engine speed as compared with vehicle speed is not within acceptable range while vehicle is running in D" range (engine running at normal operating temperature.)


DTC Chart Test Description

Numbers below refer to circled numbers on the diagnostic chart.
1. Checks for other DTCs stored in the PCM and to proceed to their respective diagnostic charts first before using this DTC chart.
2. Checks if the shift condition is intermittent.
3. Checks the condition of the transaxle range switch.
4. Checks the condition of the Vehicle Speed Sensor (transaxle).
5. Checks the condition of the Throttle Position (TP) sensor.
6. Checks the condition of shift solenoid # 1 and # 2.
7. Checks for a faulty PCM.

Diagnostic Aids:

An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation. Inspect the Powertrain Control Module (PCM) harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals and for poor terminal-to-wire connections.