Pinpoint Test O: Shift Motor Contact Plates
- Refer to Wiring Diagrams Two Wheel Drive/Four Wheel Drive Systems
for schematic and connector information.
Normal Operation and Fault Conditions
The electric shift motor is mounted externally to the transfer case. The shift motor moves during shifts in to and out of 4L, and to Neutral. The shift motor sense plate, an integral part of the shift motor assembly, informs the TCCM of the transfer case position. The sense plates are a set of 4 contacts that are opened and closed as the shift motor rotates. When shift motor movement is commanded, the TCCM will provide a voltage signal (plate power) to the four plate circuits. As each contact closes, the voltage signal is pulled low. The combination of high and low signals represent each valid transfer case shift motor position.
DTC Fault Trigger Conditions
DTC Description Fault Trigger Condition TCCM P1849:00 Transfer Case Contact Plate 'A' Short Circuit To Ground: No Sub Type Information This DTC sets when TCCM detects a short to ground. Shift motor moves are prevented when this DTC is set. The TCCM cannot complete mode change if a change in shift motor position is required. TCCM P1853:00 Transfer Case Contact Plate 'B' Short Circuit To Ground: No Sub Type Information This DTC sets when TCCM detects a short to ground. Shift motor moves are prevented when this DTC is set. The TCCM cannot complete mode change if a change in shift motor position is required. TCCM P1857:00 Transfer Case Contact Plate 'C' Short Circuit To Ground: No Sub Type Information This DTC sets when TCCM detects a short to ground. Shift motor moves are prevented when this DTC is set. The TCCM cannot complete mode change if a change in shift motor position is required. TCCM P1861:00 Transfer Case Contact Plate 'D' Short Circuit To Ground: No Sub Type Information This DTC sets when TCCM detects a short to ground. Shift motor moves are prevented when this DTC is set. The TCCM cannot complete mode change if a change in shift motor position is required. TCCM P1867:00 Transfer Case Contact Plate General Circuit Failure: No Sub Type Information This DTC sets when an invalid shift motor position is detected during selection of a new 4WD mode or during a motor movement. If the shift motor is not moving, shift motor movement is prevented. If the shift motor is moving when this DTC sets, the shift motor moves to the high-side mechanical stop. TCCM P1891:00 Transfer Case Contact Plate Ground Return Open Circuit: No Sub Type Information This DTC sets when TCCM detects a short to ground, a short to voltage or open circuit. The TCCM cannot complete mode change if a change in shift motor position is required. Possible Sources
- Wiring, terminals or connectors
- TCCM
- Shift motor
- O1 CHECK TRANSFER PLATE CONTACT PLATE CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect Transfer Case C350.
- Disconnect TCCM C2371A.
- Measure:
Positive Lead Measurement / Action Negative Lead C2371A-9 Ground C2371A-5 Ground C2371A-16 Ground C2371A-15 Ground C2371A-8 Ground
Is the resistance greater than 10, 000 ohms?
Yes GO to O2 No REPAIR the short to ground. - O2 CHECK TRANSFER PLATE CONTACT PLATE CIRCUITS FOR A SHORT TO VOLTAGE
- Disconnect Transfer Case C350.
- Disconnect TCCM C2371A.
- Ignition ON.
- Measure:
Positive Lead Measurement / Action Negative Lead C2371A-9 Ground C2371A-5 Ground C2371A-16 Ground C2371A-15 Ground C2371A-8 Ground
Is any voltage present?
Yes REPAIR the short to voltage. No GO to O3 - O3 CHECK THE TRANSFER PLATE CONTACT PLATE CIRCUITS FOR AN OPEN
- Ignition OFF.
- Disconnect Transfer Case C350.
- Disconnect TCCM C2371A.
- Measure:
Positive Lead Measurement / Action Negative Lead C2371A-9 C350-5 C2371A-5 C350-6 C2371A-16 C350-7 C2371A-15 C350-8 C2371A-8 C350-1
Are the resistances less than 3 ohms?
Yes INSTALL a new shift motor. REFER to: Transfer Case Shift Motor . No REPAIR the open circuit.