Diagnostic Routine AG
Diagnostic Routine AG
Diagnostic Overview
B272D
Refer to Wiring Diagram Set 119 for schematic and connector information Electrical Diagrams.
Normal Operation and Fault Conditions
A differential fault occurs when the cushion and backrest TEDs (Thermo-Electric Devices) on an affected seat are reporting very different temperatures to the DCSM (Dual Climate Controlled Seat Module). This may result from an air flow restriction or a circuit fault of either TED (Thermo-Electric Device). If a TED (Thermo-Electric Device) and manifold is clear of obstruction and is operational, check the other TED (Thermo-Electric Device) and circuitry on the seat. It is important to note that a TED (Thermo-Electric Device) with a higher temperature may be operating correctly and not the area of concern. The other TED (Thermo-Electric Device) may be indicating a much lower temperature, causing the DTC (Diagnostic Trouble Code) to set.
DTC Fault Trigger Conditions
Pinpoint Test
NOTICE: When taking measurements at DCSM (Dual Climate Controlled Seat Module) harness connectors, do not insert the electrical probes into the female connector pins. Inserting the probes into connector pins can cause intermittent or open electrical connections after reassembly resulting in DTCs (Diagnostic Trouble Codes) and system failure. Touching the tip of these connector pins is recommended instead.
1. CHECK THE DCSM (Dual Climate Controlled Seat Module) FOR DTCs (Diagnostic Trouble Codes)
1. Using a scan tool, perform DCSM (Dual Climate Controlled Seat Module) self-test.
Was DTC (Diagnostic Trouble Code) B272A or B272B retrieved in the self-test?
2. MONITOR THE DCSM (Dual Climate Controlled Seat Module) TED (Thermo-Electric Device) TEMPERATURE PIDs (Parameter Identifications)
1. Using a scan tool, view DCSM (Dual Climate Controlled Seat Module) PIDs (Parameter Identifications).
- Passenger cushion thermal electric device (TED (Thermo-Electric Device)) temperature (PCSHTMP)
- Passenger back TED (Thermo-Electric Device) temperature (PBKTMP)
- Seat cushion thermal electric device temperature (CSHTEMP)
- Seat back thermal electric device temperature (BK_TEMP)
2. NOTICE: Make sure the temperature of the climate controlled seats has stabilized before monitoring the PIDs (Parameter Identifications). Not allowing stabilization can cause incorrect readings and lead to incorrect identification of components that are not damaged.
Monitor the TED (Thermo-Electric Device) temperature PIDs (Parameter Identifications) with the climate controlled seats off. Compare the PIDs (Parameter Identifications) of the front passenger seat to those of the driver seat, this can help identify if there is a concern with the front passenger seat cushion or backrest PID (Parameter Identification) readings.
Are both front passenger seat TED (Thermo-Electric Device) temperature PIDs (Parameter Identifications) within 10 C (18 F) of the ambient temperature?
3. CONFIRM THE FAULT IS IN THE SEAT CUSHION OR THE BACKREST
1. Ignition OFF.
2. Start the engine.
3. NOTE: A crushed seat cushion foam pad or climate controlled seat manifold may be the cause of the fault. It may be necessary to sit on the seat or place something of reasonable size and weight on the seat to recreate the fault.
NOTE: If the seat shuts down before a 15 minute heat cycle has timed out, carry out the DCSM (Dual Climate Controlled Seat Module) self-test and go to the DCSM (Dual Climate Controlled Seat Module) DTC (Diagnostic Trouble Code) Chart to continue diagnostics DTC Chart: Dual Climate Controlled Seat Module (DCSM).
Set the passenger seat to high heat. Allow the seat to heat for at least 15 minutes while monitoring the TED (Thermo-Electric Device) temperature PIDs (Parameter Identifications) of the passenger seat. If necessary, when the seat times out after 15 minutes, set the passenger seat to high heat once again.
Do the passenger seat cushion TED (Thermo-Electric Device) and backrest TED (Thermo-Electric Device) PIDs (Parameter Identifications) vary more than 60 C (108 F) from each other?
4. CHECK THE TED (Thermo-Electric Device) COOLING PERFORMANCE
1. Check the TEDs (Thermo-Electric Devices) cooling performance on the passenger seat. REFER to Thermo-Electric Device (TED) Cooling Performance .
Did the TEDs (Thermo-Electric Devices) pass the component test?
5. CHECK THE TED (Thermo-Electric Device) INSTALLATION AND FOR A CRUSHED SEAT CUSHION
1. WARNING: Turn the ignition OFF and wait one minute to deplete the backup power supply. Failure to follow this instruction may result in serious personal injury or death in the event of an accidental deployment.
Ignition OFF.
2. Disconnect: Passenger Seat Side Air Bag C339.
3. Remove the seat. REFER to Seat .
4. Remove the seat cushion cover. REFER to Seat Cushion Cover .
5. Inspect the seat cushion:
- Is the cushion blower obstructed?
- Is the blower filter restricted or plugged?
- Is the TED (Thermo-Electric Device) correctly installed?
- Is the seat cushion foam pad crushed or restricted?
- Is the climate controlled seat manifold crushed or restricted?
Is the TED (Thermo-Electric Device) correctly installed and are the foam pad and manifold free of any damage?
6. CHECK THE PASSENGER BACKREST TED (Thermo-Electric Device)- CIRCUIT FOR A SHORT TO VOLTAGE
1. Ignition OFF.
2. Disconnect: DCSM (Dual Climate Controlled Seat Module) C3265A.
3. NOTE: Do not connect the seat side air bag electrical connector at this time.
Position the front passenger seat in the vehicle and connect the seat-to-floor connectors.
4. Ignition ON.
5. Measure:
Is any voltage present?
7. CHECK THE PASSENGER BACKREST TED (Thermo-Electric Device) CIRCUIT FOR A SHORT TO GROUND
1. Ignition OFF.
2. Measure:
Is the resistance greater than 10,000 ohms?
8. CHECK THE PASSENGER BACKREST TED (Thermo-Electric Device) AND WIRING RESISTANCE
1. Measure:
Is the resistance between 0.9 and 10 ohms?
9. CHECK THE PASSENGER BACKREST TED (Thermo-Electric Device) RESISTANCE
1. Disconnect: Passenger Backrest TED (Thermo-Electric Device) C3039.
2. Measure:
Is the resistance between 0.9 and 10 ohms?
10. CHECK THE BLOWER AND SPEED CONTROL CIRCUITS FOR A SHORT TO VOLTAGE
1. Disconnect: DCSM (Dual Climate Controlled Seat Module) C3265C.
2. Ignition ON.
3. Measure:
Is any voltage present?
11. CHECK THE BLOWER AND SPEED CONTROL CIRCUITS FOR A SHORT TO GROUND
1. Ignition OFF.
2. Measure:
Are the resistances greater than 10,000 ohms?
12. CHECK THE BLOWER AND WIRING RESISTANCE
1. Disconnect: Passenger Backrest TED (Thermo-Electric Device) C3039.
2. NOTICE: Connect the ohmmeter with the positive lead to DCSM (Dual Climate Controlled Seat Module) C3265C-8, circuit CHS08 (BN/YE) and the negative lead to DCSM (Dual Climate Controlled Seat Module) C3265C-7, circuit RHS08 (VT/WH) when measuring. Ohmmeter leads incorrectly connected can result in false readings and incorrect identification of components that are not damaged.
Measure:
Is the resistance between 4,000 ohms and 10,000 ohms?
13. CHECK THE BLOWER RESISTANCE
1. Disconnect: Passenger Cushion TED (Thermo-Electric Device) C3040.
2. NOTICE: Connect the ohmmeter with the positive lead to pin 2 and the negative lead to pin 4 when measuring. Ohmmeter leads incorrectly connected can result in false readings and lead to incorrect identification of components that are not damaged.
Measure:
Is the resistance between 4,000 ohms and 10,000 ohms?
14. CHECK THE BLOWER SPEED CONTROL AND CIRCUIT RESISTANCE
1. NOTICE: Connect the ohmmeter with the positive lead to C3265C-3, circuit VHS23 (BN/BU), harness side and the negative lead to C3265C-7, circuit RHS08 (VT/WH), harness side when measuring. Ohmmeter leads incorrectly connected can result in false readings and leads to incorrect identification of components that are not damaged.
Measure:
Is the resistance between 240,000 ohms and 420,000 ohms?
15. CHECK THE BLOWER SPEED CONTROL RESISTANCE
1. Disconnect: Passenger Cushion TED (Thermo-Electric Device) C3040.
2. NOTE: The ohmmeter must be connected with the positive lead to pin 7 and the negative lead to pin 4 when measuring. Ohmmeter leads incorrectly connected can result in false readings and lead to incorrect identification of components that are not damaged.
Measure:
Is the resistance between 240,000 ohms and 420,000 ohms?
16. CHECK THERMISTOR CIRCUIT FOR A SHORT TO VOLTAGE
1. WARNING: Turn the ignition OFF and wait one minute to deplete the backup power supply. Failure to follow this instruction may result in serious personal injury or death in the event of an accidental deployment.
Ignition OFF.
2. Disconnect: Passenger Seat Side Air Bag C339.
3. Disconnect: DCSM (Dual Climate Controlled Seat Module) C3265B.
4. Disconnect: Passenger Cushion TED (Thermo-Electric Device) C3040.
5. Ignition ON.
6. Measure:
Is any voltage present?
17. CHECK THERMISTOR CIRCUIT FOR A SHORT TO GROUND
1. Ignition OFF.
2. Measure:
Are the resistances greater than 10,000 ohms?
18. CHECK THE TED (Thermo-Electric Device) THERMISTOR AND WIRING RESISTANCE
1. Measure:
Is the resistance within the limits indicated?
19. CHECK THE THERMISTOR
1. Disconnect: Passenger Cushion TED (Thermo-Electric Device) C3040.
2. Measure:
Is the resistance within the limits indicated?
20. CHECK THE TED (Thermo-Electric Device) INSTALLATION AND FOR A CRUSHED SEAT BACKREST
1. WARNING: Turn the ignition OFF and wait one minute to deplete the backup power supply. Failure to follow this instruction may result in serious personal injury or death in the event of an accidental deployment.
Ignition OFF.
2. Disconnect: Passenger Seat Side Air Bag C339.
3. Remove the seat. REFER to Seat .
4. Remove the seat backrest cover. REFER to Seat Backrest Cover .
5. Inspect the seat backrest:
- Is the backrest blower obstructed?
- Is the blower filter restricted or plugged?
- Is the TED (Thermo-Electric Device) correctly installed?
- Is the seat backrest foam pad crushed or restricted?
- Is the climate controlled seat manifold crushed or restricted?
Is the TED (Thermo-Electric Device) correctly installed and are the foam pad and manifold free of any damage?
21. CHECK THE PASSENGER CUSHION TED (Thermo-Electric Device) CIRCUIT FOR A SHORT TO VOLTAGE
1. WARNING: Turn the ignition OFF and wait one minute to deplete the backup power supply. Failure to follow this instruction may result in serious personal injury or death in the event of an accidental deployment.
Ignition OFF.
2. Disconnect: Passenger Seat Side Air Bag C339.
3. Disconnect: DCSM (Dual Climate Controlled Seat Module) C3265A.
4. NOTE: Do not connect the seat side air bag electrical connector at this time.
Position the front passenger seat in the vehicle and connect the seat-to-floor connectors.
5. Ignition ON.
6. Measure:
Is any voltage present?
22. CHECK THE PASSENGER CUSHION TED (Thermo-Electric Device) CIRCUIT FOR A SHORT TO GROUND
1. Ignition OFF.
2. Measure:
Is the resistance greater than 10,000 ohms?
23. CHECK THE PASSENGER CUSHION TED (Thermo-Electric Device) AND WIRING RESISTANCE
1. Measure:
Is the resistance between 0.9 and 10 ohms?
24. CHECK THE PASSENGER CUSHION TED (Thermo-Electric Device) RESISTANCE
1. Disconnect: Passenger Cushion TED (Thermo-Electric Device) C3040.
2. Measure:
Is the resistance between 0.9 and 10 ohms?
25. CHECK THE BLOWER AND SPEED CONTROL CIRCUITS FOR A SHORT TO VOLTAGE
1. Disconnect: DCSM (Dual Climate Controlled Seat Module) C3265C.
2. Ignition ON.
3. Measure:
Is any voltage present?
26. CHECK THE BLOWER AND SPEED CONTROL CIRCUITS FOR A SHORT TO GROUND
1. Ignition OFF.
2. Measure:
Are the resistances greater than 10,000 ohms?
27. CHECK THE BLOWER AND WIRING RESISTANCE
1. Disconnect: Passenger Cushion TED (Thermo-Electric Device) C3040.
2. NOTICE: Connect the ohmmeter with the positive lead to DCSM (Dual Climate Controlled Seat Module) C3265C-8, circuit CHS08 (BN/YE) and the negative lead to DCSM (Dual Climate Controlled Seat Module) C3265C-7, circuit RHS08 (VT/WH) when measuring. Ohmmeter leads incorrectly connected can result in false readings and lead to incorrect identification of components that are not damaged.
Measure:
Is the resistance between 4,000 ohms and 10,000 ohms?
28. CHECK THE BLOWER RESISTANCE
1. Disconnect: Passenger Backrest TED (Thermo-Electric Device) C3039.
2. NOTICE: Connect the ohmmeter with the positive lead to pin 2 and the negative lead to pin 4 when measuring. Ohmmeter leads incorrectly connected can result in false readings and lead to incorrect identification of components that are not damaged.
Measure:
Is the resistance between 4,000 ohms and 10,000 ohms?
29. CHECK THE BLOWER SPEED CONTROL AND CIRCUIT RESISTANCE
1. NOTICE: Connect the ohmmeter with the positive lead to C3265C-4, circuit VHS21 (BU/WH), harness side and the negative lead to C3265C-7, circuit RHS08 (VT/WH), harness side when measuring. Ohmmeter leads incorrectly connected can result in false readings and lead to incorrect identification of components that are not damaged.
Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3265C-4, circuit VHS21 (BU/WH), harness side and DCSM (Dual Climate Controlled Seat Module) C3265C-7, circuit RHS08 (VT/WH), harness side.
Is the resistance between 240,000 ohms and 420,000 ohms?
30. CHECK THE BLOWER SPEED CONTROL RESISTANCE
1. Disconnect: Passenger Backrest TED (Thermo-Electric Device) C3039.
2. NOTICE: Connect the ohmmeter with the positive lead to pin 7 and the negative lead to pin 4 when measuring. Ohmmeter leads incorrectly connected can result in false readings and lead to incorrect identification of components that are not damaged.
Measure:
Is the resistance between 240,000 ohms and 420,000 ohms?
31. CHECK THERMISTOR CIRCUIT FOR A SHORT TO VOLTAGE
1. WARNING: Turn the ignition OFF and wait one minute to deplete the backup power supply. Failure to follow this instruction may result in serious personal injury or death in the event of an accidental deployment.
Ignition OFF.
2. Disconnect: Passenger Seat Side Air Bag C339.
3. Disconnect: DCSM (Dual Climate Controlled Seat Module) C3265B.
4. Disconnect: Passenger Backrest TED (Thermo-Electric Device) C3039.
5. Ignition ON.
6. Measure:
Is any voltage present?
32. CHECK THERMISTOR CIRCUIT FOR A SHORT TO GROUND
1. Ignition OFF.
2. Measure:
Is the resistance greater than 10,000 ohms?
33. CHECK THE TED (Thermo-Electric Device) THERMISTOR AND WIRING RESISTANCE
1. Connect: Passenger Backrest TED (Thermo-Electric Device) C3039.
2. Measure:
Is the resistance within the limits indicated?
34. CHECK THE TED (Thermo-Electric Device) THERMISTOR RESISTANCE
1. Disconnect: Passenger Backrest TED (Thermo-Electric Device) C3039.
2. Measure:
Is the resistance within the limits indicated?
35. CHECK FOR CORRECT DCSM (Dual Climate Controlled Seat Module) OPERATION
1. Ignition OFF.
2. Disconnect and inspect all DCSM (Dual Climate Controlled Seat Module) connectors.
3. Repair:
- corrosion (install new connector or terminals - clean module pins)
- damaged or bent pins - install new terminals/pins as necessary
- pushed-out pins - install new pins as necessary
4. Reconnect the DCSM (Dual Climate Controlled Seat Module) connectors. Make sure they seat and latch correctly.
5. Connect: Passenger Seat Backrest TED (Thermo-Electric Device) C3039 (if previously disconnected).
6. Connect: Passenger Seat Cushion TED (Thermo-Electric Device) C3040 (if previously disconnected).
7. Operate the system and determine if the concern is still present.
Is the concern still present?
36. CHECK FOR SRS (Supplemental Restraint System) DTCs (Diagnostic Trouble Codes)
1. WARNING: Turn the ignition OFF and wait one minute to deplete the backup power supply. Failure to follow this instruction may result in serious personal injury or death in the event of an accidental deployment.
Ignition OFF.
2. Connect: Passenger Seat Side Air Bag C339.
3. Connect: DCSM (Dual Climate Controlled Seat Module) C3265A, C3265B or C3265C (if previously disconnected).
4. Connect: Passenger Seat Backrest TED (Thermo-Electric Device) C3039 (if previously disconnected).
5. Connect: Passenger Seat Cushion TED (Thermo-Electric Device) C3040 (if previously disconnected).
6. Ignition ON.
7. Using a scan tool, clear the RCM (Restraints Control Module) DTCs (Diagnostic Trouble Codes).
8. Cycle the ignition OFF then ON.
9. Using a scan tool, perform RCM (Restraints Control Module) self-test.
Are any RCM (Restraints Control Module) DTCs (Diagnostic Trouble Codes) retrieved during self-test?
