Circuit Description
The memory seat module (MSM) receives inputs from the seat front vertical position sensor during memory recall, memory set, and easy exit functions. The potentiometer in the position sensor varies in resistance as the motor tilts the front of the seat. The MSM receives a variable voltage input depending on the resistance of the potentiometer. During memory set, the MSM records the voltage across the seat front vertical potentiometer. During memory recall, the MSM moves the seat front vertical motor until the voltage across the potentiometer matches the voltages stored in memory. For the easy exit function, the MSM moves the seat front vertical motor until the voltage matches what the MSM has recorded in memory for the easy exit. During normal operation, the seat front vertical position sensor is checked against out-of-range voltage limits.
Conditions for Setting the DTC
| • | The MSM will set the DTC B2118 any time it detects that the seat front vertical sensor input voltage is out of range (less than 0.25 volts or greater than 4.75 volts). |
| • | DTC B2118 will set only if DTC B1982 MSM or DTC B1983 MSM is not current. |
Action Taken When the DTC Sets
When DTC B2118 is set as current, the Memory Seat Module (MSM) will disable the seat front vertical motor during memory recall or easy exit operations. The seat front vertical motor will remain enabled for manual positioning.
Conditions for Clearing the DTC
| • | The MSM detects that the seat front vertical position sensor input is within the valid voltage range. |
| • | Use the On-Boards clearing DTCs feature. |
| • | Use a scan tool. |
Test Description
The numbers below refer to the step numbers on the diagnostic table:
-
Perform the Power Seat Systems Diagnostic System Check before continuing with the diagnosis of this DTC.
-
Multiple position sensor DTCs set indicates a concern with the reference wiring or memory seat module (MSM). Only one position sensor DTC set indicates a concern with the position sensor and wiring.
-
Clear all DTCs after the repair procedure is complete.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Was the entire Power Seat Systems Diagnostic System Check performed? | -- | |||
Were there any other position sensor DTCs set? | -- | |||
3 |
Important:: When reconnecting the position sensor connector, be sure that the connector is connected in the proper direction. It is possible to reverse the connector and cause improper memory operation. Is the resistance within the specified range? | 9000 ohms - 11,000 ohms | ||
4 | Connect a DMM from the seat front vertical position sensor cavity C (BRN/WHT) to cavity B (BLK). Is the resistance within the specified range? | 500 ohms - 9500 ohms | ||
5 |
Is the resistance less than the specified value? | 5 ohms | ||
6 | Connect a DMM from the seat front vertical position sensor connector cavity B (BLK) to the MSM connector C1 cavity 12 (BLK). Is the resistance less than the specified value? | 5 ohms | ||
7 | Connect a DMM from the seat front vertical position sensor connector cavity C (BRN/WHT) to ground. Is the resistance less than the specified value? | 5 ohms | ||
8 | Connect a DMM from the seat front vertical position sensor connector cavity C (BRN/WHT) to the MSM connector C1 cavity 15 (BRN/WHT). Is the resistance less than the specified value? | 5 ohms | ||
9 |
Is the resistance less than the specified value? | 5 ohms | ||
10 | Connect a DMM from the seat front vertical position sensor connector cavity D (GRY) to the MSM connector C1 cavity 13 (GRY). Is the resistance less than the specified value? | 5 ohms | ||
11 | Connect a DMM from the seat front vertical position sensor connector cavity B (BLK) to the MSM connector C1 cavity 12 (BLK). Is the resistance less than the specified value? | 5 ohms | ||
12 | Replace the seat front vertical position sensor. Refer to Seat Horizontal and Vertical Drive Cable Replacement . Is the seat front vertical position sensor replacement complete? | -- | -- | |
13 | Repair the open in CKT 788 (GRY) between the S348 and the seat front vertical position sensor. Refer to Wiring Repairs in Wiring Systems. Is the circuit repair complete? | -- | -- | |
14 | Repair the open in CKT 782 (BLK) between S349 and the seat front vertical position sensor. Refer to Wiring Repairs in Wiring Systems. Is the circuit repair complete? | -- | -- | |
15 | Repair the short in CKT 557 (BRN/WHT). Refer to Wiring Repairs in Wiring Systems. Is the circuit repair complete? | -- | -- | |
16 | Repair the open in CKT 557 (BRN/WHT) between the MSM and the seat front vertical position sensor. Refer to Wiring Repairs in Wiring Systems. Is the circuit repair complete? | -- | -- | |
17 | Repair the short in CKT 788 (GRY). Refer to Wiring Repairs in Wiring Systems. Is the circuit repair complete? | -- | -- | |
18 | Repair the open in CKT 788 (GRY) between the MSM and S348. Refer to Wiring Repairs in Wiring Systems. Is the circuit repair complete? | -- | -- | |
19 | Repair the open in CKT 782 (BLK) between the MSM and the S349. Refer to Wiring Repairs in Wiring Systems. Is the circuit repair complete? | -- | -- | |
20 | Replace the memory seat module (MSM). Refer to Memory Seat Control Module Replacement . Is the MSM replacement complete? | -- | -- | |
Are all DTCs cleared? | -- | -- |
