B1860 Driver Lumbar Vert Sensor CKT Malf (With AM3)

Diagnostic Chart (Part 1 Of 3):

Diagnostic Chart (Part 2 Of 3):

Diagnostic Chart (Part 3 Of 3):

Schematic:

CIRCUIT DESCRIPTION
The sensor that sets this diagnostic trouble code (DTC) monitors the seat lumbar vertical position. The sensor 5 V reference and ground are supplied by the memory seat module (MSM). The sensor output signal is sent directly to the massage module. The massage module checks this signal to determine seat position and then relays the information to the MSM. During lumbar massage operation, the massage module sends a simulated lumbar vertical position signal to the MSM. This prevents the MSM from seeing the lumbar up/down motion and erroneously setting a code.

CONDITIONS FOR RUNNING THE DTC
The MSM must be powered and can not have B1327-Battery Voltage Low set as an active DTC for this DTC to set.

CONDITIONS FOR SETTING THE DTC
If the MSM sees the input from this sensor as either lower than 0.25 V or higher than 4.75 V, the sensor will be considered out of range and the MSM will set this DTC.

ACTION TAKEN WHEN DTC SETS
The MSM disables the memory recall and easy exit/entry action commands of the motor monitored by the sensor. The motor will respond to manual positioning commands.

CONDITIONS FOR CLEARING THE MIL/DTC
The MSM will clear the DTC as an active malfunction when the MSM sees the analog input from this sensor as between 0.25 V and 4.15 V during one cycle of checking the MSM inputs.

DIAGNOSTIC AIDS
^ If the 5 volt reference circuit is shorted to ground multiple codes will set.
^ If the 5 volt reference circuit is open at the massage module (AM3) multiple codes will set.
^ If the sensor ground circuit is open multiple codes will set.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
3. Tests for the proper operation of the circuit in the high voltage range.
7. Tests for the proper operation of the circuit in the low voltage range.
25. This step verifies the repair.

For a description of the RPO Code(s) shown in this image/article refer to the RPO Code List found at Vehicle/Application ID RPO Codes