B1740
DTC B1735, B1740, B1745, B1750, B1755, B1760, B1815, or B1820
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptors
DTC B1735 02
-
Driver Seat Front Up Switch Circuit Short to Ground
DTC B1740 02
-
Driver Seat Front Down Switch Circuit Short to Ground
DTC B1745 02
-
Driver Seat Rear Up Switch Circuit Short to Ground
DTC B1750 02
-
Driver Seat Rear Down Switch Circuit Short to Ground
DTC B1755 02
-
Driver Seat Assembly Forward Switch Circuit Short to Ground
DTC B1760 02
-
Driver Seat Assembly Rearward Switch Circuit Short to Ground
DTC B1815 02
-
Driver Seat Recline Forward Switch Circuit Short to Ground
DTC B1820 02
-
Driver Seat Recline Rearward Switch Circuit Short to Ground
Diagnostic Fault Information
Circuit/System Description
The seat memory control module supplies a reference voltage to each signal circuit of the driver seat adjuster switch. When the power seat switches are pressed, the appropriate signal circuit from the seat memory control module is pulled low through the switch contacts indicating the power seat command. The seat memory control module then commands the driver seat to move in response to the switch signals.
Conditions for Running the DTC
* DTC B1325 must not be present.
* Module battery voltage must be between 9-16 V.
Conditions for Setting the DTC
* If a seat switch circuit is active in one direction and the switch for the opposite direction is pressed, this DTC will set.
* A short to ground on a switch signal circuit.
Action Taken When the DTC Sets
* A motor output driven in response to a switch considered failed, is deactivated for both directions.
* All memory recall commands are ignored.
* The seat memory control module will respond to any other switch signal that has not set a DTC.
Conditions for Clearing the DTC
* The current DTC will clear and set the DTC to history, when the fault is no longer present and the ignition is cycled OFF then back to ACC or RUN.
* The history DTC will clear after 40 consecutive fault-free ignition cycles have occurred.
Diagnostic Aids
* If one of the switch signal circuits is shorted to ground, multiple DTCs will set.
* If a switch is stuck in one direction and the switch is pressed in the opposite direction, a single DTC will set.
Reference Information
Schematic Reference
Driver Seat Schematics Driver Seat Schematics
Connector End View Reference
Component Connector End Views Sunshade - Left (DH6)
Description and Operation
Memory Seats Description and Operation Memory Seats
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify the scan tool seat switch parameters listed below change between Inactive and Forward/Rearward or UP/Down when pressing the appropriate seat directional switch.
* Driver Seat Cushion Front Vertical Switch
* Driver Seat Cushion Rear Vertical Switch
* Driver Seat Horizontal Switch
* Driver Seat Back Switch
• If the parameter does not change
Refer to Circuit/System Testing.
• If the parameter changes
3. All OK.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the S64D driver seat adjuster switch.
2. Verify that all scan tool driver seat switch parameters listed below are Inactive:
* Driver Seat Cushion Front Vertical Switch
* Driver Seat Cushion Rear Vertical Switch
* Driver Seat Horizontal Switch
* Driver Seat Back Switch
• If not Inactive
1. Ignition OFF, disconnect the harness connector at the K40 seat memory control module, ignition ON.
2. Test for infinite resistance between the appropriate signal circuit terminal listed below and ground:
* Front vertical upward switch terminal A
* Front vertical downward switch terminal K
* Rear vertical upward switch terminal F
* Rear vertical downward switch terminal J
* Horizontal forward switch terminal D
* Horizontal rearward switch terminal C
* Recline forward switch terminal H
* Recline rearward switch terminal G
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K40 seat memory control module.
• If Inactive
3. Install a 3 A fused jumper wire between the appropriate signal circuit terminal listed below and the ground circuit terminal E.
* Front vertical upward switch terminal A
* Front vertical downward switch terminal K
* Rear vertical upward switch terminal F
* Rear vertical downward switch terminal J
* Horizontal forward switch terminal D
* Horizontal rearward switch terminal C
* Recline forward switch terminal H
* Recline rearward switch terminal G
4. Verify the scan tool seat switch parameter is Forward/Rearward or UP/Down.
• If not Forward/Rearward or UP/Down
1. Ignition OFF, disconnect the harness connector at the K40 seat memory control module, ignition ON.
2. Test for less than 1 V between the signal circuit terminal and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V
3. Ignition OFF.
4. Test for less than 2 ohms in the signal circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K40 seat memory control module.
• If Forward/Rearward or UP/Down
5. Test or replace the S64D driver seat adjuster switch.
Component Testing
Seat Adjuster Switch Test
1. Ignition OFF, disconnect the harness connector at the S64D driver seat adjuster switch.
2. Test for infinite resistance between the ground terminal E and each signal terminal with the switch in the open position.
• If less than infinite resistance
Replace the S64D driver seat adjuster switch.
• If infinite resistance
3. Test for less than 2 omhs between the ground terminal E and each signal terminal with the appropriate switch in the closed position.
• If 2 omhs or greater
Replace the S64D driver seat adjuster switch.
• If less than 2 omhs
4. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Driver Seat Adjuster and Recliner Switch Replacement Driver Seat Adjuster and Recliner Switch Replacement
* Control Module References Control Module References for seat memory control module replacement, programming and setup