Pinpoint Test F : Shift Fork Actuator - Electrical Fault: Notes
Refer to Transmission Controls for schematic and connector information.
Normal Operation and Fault Conditions
The shift system consists of two independent sub-systems controlling the transmission synchronizer pre-selections and engagements. This arrangement provides independent control of the two transmission and a mechanical interlock that prevents two gears within the same transmission from being engaged simultaneously. The TCM contains two electric motors that mesh with and drive the first double gear wheel, which drives the second double gear which finally drives the shift drum. Gearing between the shift motors and the drums reduce speed and multiply torque. Position sensors in the TCM detect motor position. Shift drum position is learned by the TCM during a teach-in process that involves rotating each drum.
DTC Fault Trigger Conditions
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| P2831 | Shift Fork "A" Position Circuit | Shift drum motor 1 fault detected. |
| P2832 | Shift Fork "A" Position Circuit Range/Performance | TCM found an error with shift drum 1 that indicated it has lost position. |
| P2835 | Shift Fork "A" Position Circuit Intermittent | Shift drum motor 1 sequence fault detected. |
| P2836 | Shift Fork "B" Position Circuit | Shift drum motor 2 fault detected. |
| P2837 | Shift Fork "B" Position Circuit Range/Performance | TCM found an error with shift drum 2 that indicated it has lost position. |
| P283A | Shift Fork "B" Position Circuit Intermittent | Shift drum motor 2 sequence fault detected. |
| P285B | Shift Fork "A" Actuator Circuit / Open | Shift drum motor 1 open circuit fault detected. |
| P285C | Shift Fork "A" Actuator Circuit Performance | This DTC sets with P285B, P285D and/or P285E. Used to light the wrench lamp. |
| P285D | Shift Fork "A" Actuator Circuit Low | Shift drum motor 1 short to ground fault detected. |
| P285E | Shift Fork "A" Actuator Circuit High | Shift drum motor 1 short to power fault detected. |
| P285F | Shift Fork "B" Actuator Circuit / Open | Shift drum motor 2 open circuit fault detected. |
| P2860 | Shift Fork "B" Actuator Circuit Performance | This DTC sets with P285F, P2861 and/or P2862. Used to light the wrench lamp. |
| P2861 | Shift Fork "B" Actuator Circuit Low | Shift drum motor 2 short to ground fault detected. |
| P2862 | Shift Fork "B" Actuator Circuit High | Shift drum motor 2 short to power fault detected. |
Possible Sources
- Connectors damaged or pushed-out terminals, corrosion, loose wires and missing or damaged seals
- Shift drum motor 1
- Shift drum motor 2
- TCM