Circuit Description
The mobility seat module uses inputs from 4 limit switches in order to determine the seat position. The limit switch signal circuits are referenced from battery voltage within the module. The limit switches will open or close the switch signal circuits to ground in order for the module to determine them to be active or inactive. The lift upper limit switch signal circuit is considered to be active when the circuit reference voltage is high or open to ground by the switch.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC 051 Lift Upper Limit Switch Active at Start of Ascend
Conditions for Running the DTC
| • | Battery voltage must be within 9-16 volts. |
| • | Seat ascend operation is attempted from the out of vehicle position. |
Conditions for Setting the DTC
When seat ascend operation is attempted from the out of vehicle position, the lift upper limit switch signal to the module is high or active.
Action Taken When the DTC Sets
While the fault is current, the module will not allow the seat to ascend to the in vehicle outward facing position.
Conditions for Clearing the DTC
The DTC may be cleared by removing the main power supply or ground from the seat module.
Diagnostic Aids
Inspect the limit switch for any physical damage or obstructions to its mechanical operation which may cause the condition.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Power Seats Schematics | |||
1 | Did you review the description and operation and perform the necessary inspections? | Go to Step 2 | Go to Symptoms - Seats |
2 | Verify the fault is present. Does the system operate normally? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 |
3 |
Does the seat ascend to the in vehicle outward facing position? | Go to Step 5 | Go to Step 4 |
4 | Test the lift upper limit switch signal circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 6 |
5 | Test the lift upper limit switch ground circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 8 |
6 | Inspect for poor connections at the mobility seat module harness connectors. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 7 |
7 | Replace the mobility seat control module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Is the repair complete? | Go to Step 9 | -- |
8 | Replace the mobility seat base unit. Refer to Sit-N-Lift Seat Base Replacement . Is the repair complete? | Go to Step 9 | -- |
9 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3 |
