B1860 (With RPO Code AM3)

DTC B1860 (WITH MASSAGING LUMBAR-AM3)

CIRCUIT DESCRIPTION
The position sensor that sets this diagnostic trouble code (DTC) is attached to the lumbar directional motor it monitors. It receives a 5-volt reference and low reference from the memory seat module (MSM). The sensor sends a voltage signal that varies with the movement of the seat through the signal circuit to the MSM. Then based on this voltage signal, the MSM determines the position of the seat.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC B1860 Seat Lumbar Vertical Position Sensor Circuit

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 analog input from this sensor as either lower than 0.25 volt or higher than 4.75 volt, the sensor will be considered out of range and the MSM will set this DTC.

ACTION TAKEN WHEN THE 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 DTC
The MSM will clear the DTC as an active malfunction when it sees the analog input from this sensor as between 0.25 volt and 4.75 volt during one cycle of checking the MSM inputs.

DIAGNOSTIC AIDS
- All position sensors use common ground and 5-volt reference circuits.
- If the 5-volt reference circuit is shorted to voltage multiple codes will set.
- 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 multiple codes will set.
- If the sensor ground circuit is open multiple codes will set.

TEST DESCRIPTION

Steps 1 - 9:

Steps 10 - 21:

Steps 22 - 25:

The numbers below refer to the step numbers on the diagnostic table.
3. Tests for the proper operation of the signal circuit in the high voltage range.
7. Tests for the proper operation of the signal circuit in the low voltage range.
8. This step tests the integrity of the lumbar vertical position sensor signal circuit. If the fuse in the jumper wire opens when you perform this test, a short to battery voltage may have occurred.
25. This step verifies the repair.