Test Description
The numbers below refer to the step numbers on the diagnostic table.
- 2: The lack of communication may be caused by a partial or a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
- 4: If no DTCs are present refer to the symptom list in Symptoms in order to determine the correct diagnostic procedure to use.
- 5: The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will collect all the available information before tests are performed.
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Install a scan tool. Does the scan tool power up? | Go to Step 2 | Go to Scan Tool Does Not Power Up in Data Link Communications |
| 2 | Turn ON the ignition, with the engine OFF. Attempt to establish communication with the following control modules: Powertrain control module Body control module Driver door module Passenger door module Driver seat module Does the scan tool communicate with the listed control modules? | Go to Step 3 | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications |
| 3 | IMPORTANT: The engine may start during the following step. Turn off the engine as soon as you have observed the Crank power mode. Access the Class 2 Power Mode in the Diagnostic Circuit Check on the scan tool. Rotate the ignition switch through all of the positions while observing the ignition switch power mode parameter. Do the ignition switch power mode parameter readings match the actual ignition switch positions? | Go to Step 4 | Go to Power Mode Mismatch in Body Control System |
| 4 | Select the display DTCs function on the scan tool for the following control modules: Powertrain control module Body control module Driver door module Passenger door module Driver seat module Does the scan tool display any DTCs? | Go to Step 5 | Go to Symptoms - Seats |
| 5 | Does the scan tool display any DTC that begins with a "U"? | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications | Go to Step 6 |
| 6 | Does the scan tool display B1000? | Go to Diagnostic Trouble Code (DTC) List in Body Control System | Go to Step 7 |
| 7 | Does the scan tool display DTC P0562 or P0563? | Go to Diagnostic Trouble Code (DTC) List in Engine Electrical | Go to Diagnostic Trouble Code (DTC) List |
| IMPORTANT |
|---|
| The engine may start during the following step. Turn off the engine as soon as you have observed the Crank power mode. |
Diagnostic System Check - Power Seat Systems
The numbers below refer to the step numbers on the diagnostic table.
- 3: Tests for the proper operation of the signal circuit in the low voltage range.
- 4: Tests for the proper operation of the signal circuit in the high voltage range.
- 5: Tests for a short to voltage in the 5-volt reference circuit.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Driver Seat Schematics Connector End View Reference: Power Seat Systems Connector End Views | ||||
| 1 | Did you perform the Power Seat Systems Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Power Seat Systems | |
| 2 | Install a scan tool. With a scan tool, observe the Recline Position Sensor parameter in the driver seat module (DSM) Sensor Data list. Is the Recline Position Sensor parameter within the specified range? | 0.39-4.58 V | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 |
| 3 | Disconnect the recline motor position sensor. With a scan tool, observe the Recline Position Sensor parameter. Is the Recline Position Sensor parameter less than the specified value? | 0.39 V | Go to Step 4 | Go to Step 8 |
| 4 | Connect a 3-ampere fused jumper wire between the signal circuit of the recline position sensor and the 5-volt reference circuit of the recline position sensor. With a scan tool, observe the Recline Position Sensor parameter. Is the Recline Position Sensor parameter greater than the specified value? | 4.58 V | Go to Step 5 | Go to Step 7 |
| 5 | Disconnect the fused jumper wire. Measure the voltage between the 5-volt reference and the signal circuit of the recline position sensor. Is the voltage greater than the specified value? | 5 V | Go to Step 6 | Go to Step 10 |
| 6 | Test the 5-volt reference circuit of the recline position sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 12 | |
| 7 | Test the 5-volt reference circuit of the recline position sensor for one of the following conditions: A short to ground A high resistance An open Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 9 | |
| 8 | Test the signal circuit of the recline position sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 12 | |
| 9 | Test the signal circuit of the recline position sensor for one of the following conditions: A short to ground A high resistance An open Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 12 | |
| 10 | Test the low reference circuit of the recline position sensor for one of the following conditions: A high resistance An open Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 11 | |
| 11 | Inspect for poor connections at the harness connector of the recline position sensor. 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 15 | Go to Step 13 | |
| 12 | Inspect for poor connections at the harness connector of the DSM. 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 15 | Go to Step 14 | |
| 13 | Replace the recline position sensor. Did you complete the replacement? | Go to Step 15 | ||
| 14 | Replace the DSM. Refer to Memory Seat Control Module Replacement . Did you complete the replacement? | Go to Step 15 | ||
| 15 | Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC. Does the DTC reset? | Go to Step 2 | System OK | |
DTC B1825
The numbers below refer to the step numbers on the diagnostic table.
- 3: During this test the DSM must see an active switch input before power will be supplied the position sensor.
- 4: During this test the DSM must see an active switch input before power will be supplied the position sensor.
- 5: During this test the DSM must see an active switch input before power will be supplied the position sensor.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Driver Seat Schematics Connector End View Reference: Power Seat Systems Connector End Views | |||
| 1 | Did you perform the Power Seat Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Power Seat Systems |
| 2 | Verify the condition is present. Does the system operate normally? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 |
| 3 | Disconnect the position sensor connector to the motor for which the DTC has set. Connect a DMM from the positive voltage reference circuit terminal in the position sensor harness connector to a good ground. Press the adjuster switch in either direction. Does the DMM display battery voltage when the adjuster switch is pressed? | Go to Step 4 | Go to Step 6 |
| 4 | Connect a DMM from the positive voltage reference circuit terminal to the low reference circuit terminal in the position sensor harness connector. Press the adjuster switch in either direction. Does the DMM display battery voltage when the adjuster switch is pressed? | Go to Step 5 | Go to Step 7 |
| 5 | Connect a DMM from the signal circuit terminal to the low reference circuit terminal in the position sensor harness connector. Press the adjuster switch in either direction. Does the DMM display battery voltage when the adjuster switch is pressed? | Go to Step 9 | Go to Step 8 |
| 6 | Test the position sensor positive voltage reference circuit for the following conditions: An open A short to ground A short to voltage Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 10 |
| 7 | Test the position sensor low reference circuit for an open or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 10 |
| 8 | Test the position sensor signal circuit for the following conditions: An open A short to ground A short to voltage Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 10 |
| 9 | Inspect for poor connections at the adjuster motor connector. 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 13 | Go to Step 11 |
| 10 | Inspect for poor connections at the harness connector of the driver seat module (DSM). 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 13 | Go to Step 12 |
| 11 | Replace the appropriate adjuster motor assembly. Refer to Seat Adjuster Motor Replacement - Front or Lumbar Replacement - Front Seat . Did you complete the replacement? | Go to Step 13 | |
| 12 | Replace the DSM. Refer to Memory Seat Control Module Replacement . Did you complete the replacement? | Go to Step 13 | |
| 13 | Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC. Does the DTC reset? | Go to Step 3 | System OK |
DTC B1850, B1860, B1960, B2355, B2365, or B2375
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.
- 4: Tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens upon performing this test, the signal circuit has a short to voltage.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Driver Seat Schematics , Passenger Seat Schematics Connector End View Reference: Power Seat Systems Connector End Views | ||||
| 1 | Did you perform the Power Seat Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Power Seat Systems | |
| 2 | Install a scan tool. Start the engine. Turn the heated seat ON. With a scan tool, observe the Heated Seat Sensor parameter in the data list for the driver seat module (DSM). Does the scan tool indicate that the Heated Seat Sensor parameter is within the specified range? | 0.078-4.94 V | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 |
| 3 | Turn OFF the ignition. Disconnect the heated seat back 4-way connector. Start the engine. Turn the heated seat ON. With a scan tool, observe the Heated Seat Sensor parameter. Is the Heated Seat Sensor parameter greater than the specified value? | 4.5 V | Go to Step 4 | Go to Step 5 |
| 4 | Turn OFF the ignition. Connect a 3-ampere fused jumper wire between the signal circuit of the heated seat sensor and the low reference circuit of the heated seat sensor. Start the engine. Turn the heated seat ON. With a scan tool, observe the Heated Seat Sensor parameter. Is the Heated Seat Sensor parameter less than the specified value? | 0.5 V | Go to Step 8 | Go to Step 6 |
| 5 | Test the signal circuit of the heated seat sensor for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 9 | |
| 6 | Test the signal circuit of the heated seat sensor for one of the following conditions: A short to voltage A high resistance An open Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 7 | |
| 7 | Test the low reference circuit of the heated seat sensor for one of the following conditions: A high resistance An open Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 9 | |
| 8 | Inspect for poor connections at the harness connector of the heated seat sensor. 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 12 | Go to Step 10 | |
| 9 | Inspect for poor connections at the harness connectors of the DSM. 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 12 | Go to Step 11 | |
| 10 | Replace the seat back heater element. Refer to Seat Back Heater Element Replacement - Front . Did you complete the replacement? | Go to Step 12 | ||
| 11 | Replace the DSM. Refer to Memory Seat Control Module Replacement . Did you complete the replacement? | Go to Step 12 | ||
| 12 | Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC. Does the DTC reset? | Go to Step 2 | System OK | |
DTC B2435 or B2440
Lumbar Support/Torso Bolster System Operation
The power lumbar support/torso bolster system is only available with the driver memory, 8 way power seats option. The driver seat lumbar and torso adjuster motors are controlled through the driver seat module, while the passenger seat lumbar and torso adjuster motors are controlled directly through the lumbar support/torso bolster adjuster switch.
The driver seat module supplies the driver seat lumbar support/torso bolster adjuster switch assembly with a battery positive reference voltage. While the switches are in an inactive state the switch contacts are closed to the switch ground circuit. When a switch is pressed to an active state the switch contact is closed to the reference voltage circuit. Battery voltage on a switch signal circuit indicates to the driver seat module the switch status is active. Each seat adjuster motor is controlled by the driver seat module through 2 motor control circuits. While the seat adjuster motors are in an inactive state the motor control circuits are closed to ground circuit contacts within the driver seat module. The driver seat module operates the seat adjuster motors by switching one of a motor's control circuits to battery voltage. The seat adjuster motors are bidirectional and the direction of adjuster motor rotation is determined by which of the adjuster motor control circuits is switched to battery voltage while the other remains grounded.
The seat adjuster motors are equipped with internal position sensors. The adjuster motor position sensors are monitored by the driver seat module and are used to determine the seat position when storing or recalling memory settings. The lumbar and torso adjuster motors use hall effect type position sensors. The hall effect position sensors are supplied with battery positive reference and ground circuits from the driver seat module. The position sensor signal circuits are supplied battery positive voltage through a resistor them monitored within the driver seat module. During adjuster motor operation the hall effect position sensor provides a single pulse for every revolution of the adjuster motor shaft. The driver seat module counts the pulses from the position sensor signal circuits to determine the adjuster motor positions when storing or recalling memory seat position settings.
Battery voltage is supplied to the passenger seat lumbar support/torso bolster switch through the SEAT 30A circuit breaker. While the switches are in an inactive state the switch contacts are closed to the switch ground circuit. When a switch is pressed to an active state the switch contact is closed to the battery voltage supply circuit. Each motor is controlled by the power seat switch through 2 motor control circuits. The motors are bidirectional and the direction of motor rotation is determined by which of the motor control circuits is switched to battery voltage while the other remains grounded.
Memory Set/Recall Operation
The seat adjuster motors are equipped with internal position sensors. The adjuster motor position sensors are monitored by the driver seat module and are used to determine the seat position when storing or recalling memory settings. The horizontal, front vertical, and rear vertical adjuster motors use hall effect type position sensors. The hall effect position sensors are supplied with battery positive reference and ground circuits from the driver seat module. The position sensor signal circuits are supplied battery positive voltage through a resistor them monitored within the driver seat module. During adjuster motor operation the hall effect position sensor provides a single pulse for every revolution of the adjuster motor shaft. The driver seat module counts the pulses from the position sensor signal circuits to determine the adjuster motor positions when storing or recalling memory seat position settings. The recline adjuster motor is equipped with a potentiometer type position sensor. The recline motor position sensor is supplied with it's own 5-volt reference ground circuits from the driver seat module. The recline position sensor signal circuit is referenced from ground within the driver seat module. The signal voltage monitored by the driver seat module ranges from 0.39 - 4.58 volts and is determined by the wiper location on the resistor within the recline motor position sensor. The recline motor position sensor signal circuit voltage level is used by the driver seat module to determine the seat recline position when storing or recalling memory seat position settings.
The memory recall switch assembly on the driver's door provides inputs to the driver door module. Battery voltage is supplied to the memory recall switch assembly from the driver door module. When a RCL 1, RCL 2, or EXIT switch is pressed, the switch contacts close the appropriate switch signal circuit to the battery voltage supply circuit within the memory recall switch assembly. When the driver door module receives active switch signals from the memory recall switch assembly, the appropriate commands are sent to the driver seat module using the Class 2 Serial Data circuit.
Memory seat recall operation is allowed only with the transmission selector lever in the PARK position while the ignition is on. The transmission selector lever position data is provided to the driver seat module by a message through the Class 2 Serial Data circuit.