Pinpoint Test G : GSM (Gearshift Module) Communication: Notes
WARNING: This page is about a different car, the 2015 Lincoln MKZ. However, it is still accessible from the selected car via links, so may be relevant.
Diagnostic Overview
Diagnostics in this article assume a certain skill level and knowledge of Ford-specific diagnostic practices. Refer to: Diagnostic Methods .
Refer to Transmission Controls for schematic and connector information.
Normal Operation and Fault Conditions
The TRCM, GSM and the PCM communicate on the HS-CAN but use a redundant PWM hard wired system as a backup. If the HS-CAN system fails the TRCM, GSM and PCM communicate via this hard wired system. The GSM sends a PWM signal to the PCM when the CAN system is down so the PCM knows what range the operator has selected. The PWM operates at 2 frequencies, 190 Hz and 230 Hz and outputs 8 duty cycles.
DTC Fault Trigger Conditions
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| P085D | Gear Shift Control Module "A" Performance | The PCM detects a frequency signal less than 170 Hz or greater than 250 Hz. |
| P0860 | Gear Shift Control Module "A" Communication Circuit | The TRCM or the PCM detects a PWM signal out of range. |
| P0861 | Gear Shift Control Module "A" Communication Circuit Low | The TRCM or the PCM detects a duty cycle less than 10%. |
| P0862 | Gear Shift Control Module "A" Communication Circuit High | The TRCM or the PCM detects a duty cycle greater than 90%. |
Possible Sources
- Connectors damaged or pushed-out terminals, circuitry open, shorted to power or shorted to ground
- BCM fuse 12 (7.5A)
- GSM