Part 1
Seats
Pinpoint Test AO: DTC B272C
Refer to Wiring Diagram Set 119, Climate Controlled Seats for schematic and connector information. [1][2]Diagrams By Number
Normal Operation
The Dual Climate Controlled Seat Module (DCSM) is supplied voltage at all times, but the climate controlled seat system only operates with the engine running. The system can be operated with the ignition ON engine OFF by using a scan tool to bypass the climate controlled seat buttons on the touchscreen interface. When commanding a heat or cool mode operation in this manner, the climate controlled seat system only operates in 15-second intervals. Both voltage supply circuits are spliced together internal to the DCSM (Dual Climate Controlled Seat Module) , so if one circuit becomes open, both seats can still be operated. However, if a fault occurs setting a DTC specific to either climate controlled seat, only the affected seat is disabled by the DCSM (Dual Climate Controlled Seat Module).
The seat cushion is equipped with a Thermo-Electric Device (TED) assembly that includes a seat blower (fan motor, serviced as an assembly with the TED (Thermo-Electric Device)). Similarly, the seat backrest is also equipped with its own TED (Thermo-Electric Device) assembly with blower. Cabin air is drawn through the blower and distributed to each of the TED (Thermo-Electric Device) modules located in the seat cushion and backrest. The TEDs (Thermo-Electric Devices) then heat or cool the air. The air is then directed into the foam pad and manifold where it is distributed along the surface of the cushion and backrest of the seat. Once the system is activated, the DCSM (Dual Climate Controlled Seat Module) uses a set of flexible algorithms to control the heating/cooling modes and the blower speed dependant on the HVAC module seat switch settings.
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 airflow restriction or a circuit fault of either TED (Thermo-Electric Device) area. If a TED (Thermo-Electric Device) and manifold is clear of obstruction and is operational, the other TED (Thermo-Electric Device) and circuitry on the seat should be checked. 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 to set.
- DTC B272C (Driver Differential Temperature Fault)- If there is a temperature differential between the driver backrest and cushion TED (Thermo-Electric Device) of 60°C (108°F) or more for more than 4 seconds, the TED (Thermo-Electric Device) is disconnected or the duct is blocked, this DTC will set. When this happens the first time in a key cycle, the DCSM (Dual Climate Controlled Seat Module) puts the driver seat system into recovery mode (see principles of operation). If the system is able to recover, it will function normally. If the system is able to recover and it occurs a second time in the same key cycle, the DCSM (Dual Climate Controlled Seat Module) will shut down the driver seat system. Principles of Operation
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Restricted cushion or backrest TED (Thermo-Electric Device) filter
- Crushed or restricted cushion or backrest foam pad
- Crushed or restricted cushion or backrest climate controlled seat manifold
- Cushion or backrest TED (Thermo-Electric Device) assembly
- DCSM (Dual Climate Controlled Seat Module)
PINPOINT TEST AO : DTC B272C
NOTICE: When taking measurements at Dual Climate Controlled Seat Module (DCSM) 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 Diagnostic Trouble Codes (DTCs) and system failure. Touching the tip of these connector pins is recommended instead.
NOTE: If a seat equipped with a seat mounted side air bag is being serviced, the Supplemental Restraint System (SRS) must be depowered. Refer to Restraints and Safety Systems &/or Air Bag Systems.
NOTE: The air bag warning lamp illuminates when the Restraints Control Module (RCM) fuse is removed and the ignition switch is ON. This is normal operation and does not indicate an SRS (Supplemental Restraint System) fault.
NOTE: The SRS (Supplemental Restraint System) must be fully operational and free of faults before releasing the vehicle to the customer.
AO1 CHECK FOR DCSM (Dual Climate Controlled Seat Module) DTCs
- Enter the following diagnostic mode on the scan tool: Self Test- DCSM (Dual Climate Controlled Seat Module).
Was DTC B2729 or B2730 retrieved?
Yes
For DTC B2729, GO to Pinpoint Test AL. For DTC B2730, GO to Pinpoint Test AS. Pinpoint Test AL: DTC B2729 Pinpoint Test AS: DTC B2730
No
GO to AO2.
AO2 MONITOR THE TED (Thermo-Electric Device) TEMPERATURE PIDs
- Enter the following diagnostic mode on the scan tool: DataLogger- DCSM (Dual Climate Controlled Seat Module)- PIDs.
- Passenger Cushion Thermal Electric Device (TED) Temperature (PCSHTMP)
- Passenger Back TED Temperature (PBKTMP)
- Seat cushion thermal electric device temperature (CSHTEMP)
- Seat back thermal electric device temperature (BK_TEMP)
- NOTE: Make sure the temperature of the climate controlled seats has stabilized before monitoring the PIDs. Not allowing stabilization can cause incorrect readings and lead to incorrect identification of components that are not faulty.
Monitor TED (Thermo-Electric Device) temperature PIDs with the climate controlled seats OFF. Compare the PID values of the driver seat to those of the front passenger seat, this can help identify if there is a concern with the driver seat cushion or backrest PID value readings.
Are both driver seat TED (Thermo-Electric Device) temperature PIDs within 10°C (18°F) of the ambient temperature?
Yes
GO to AO3.
No
If the driver seat cushion PID varies 10°C (18°F) or more from ambient temperature, GO to AO16.
If the driver seat backrest PID varies 10°C (18°F) or more from ambient temperature, GO to AO32.
AO3 CONFIRM THE FAULT IS IN THE SEAT CUSHION OR THE BACKREST
- Ignition OFF.
- Ignition ON.
- NOTE: A crushed seat cushion foam pad or a crushed 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 Dual Climate Controlled Seat Module (DCSM) DTC Chart to continue diagnostics. Dual Climate Controlled Seat Module (DCSM) DTC Chart
After cycling the ignition and with the engine running, set the driver seat to high heat (3 indicators illuminated on HVAC module). Allow the seat to heat for at least 15 minutes while monitoring the TED (Thermo-Electric Device) temperature PIDs of the driver seat. If necessary, when the seat times-out after 15 minutes, set the driver seat to high heat once again.
Do the driver seat cushion TED (Thermo-Electric Device) and backrest TED (Thermo-Electric Device) PIDs vary more than 60°C (108°F)
from each other?
Yes
If the driver seat cushion PID is 60°C (108°F) hotter than the backrest PID, GO to AO5.
If the driver seat backrest PID is 60°C (108°F) hotter than the cushion PID, GO to AO20.
No
GO to AO4.
AO4 CHECK THE TEDs (Thermo-Electric Devices) COOLING PERFORMANCE
- Check the TEDs (Thermo-Electric Devices) cooling performance on the affected seat. Refer to Component Test- Thermo-Electric Device (TED) Cooling Performance. Component Tests and General Diagnostics
Did the TEDs (Thermo-Electric Devices) pass the component test?
Yes
The DTC may have been set by extreme cabin temperatures or excessive sunload on the seat causing the system to enter recovery mode. Occupant size and weight characteristics can also be a factor. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. If a concern cannot be found or duplicated, RETURN the vehicle to the customer.
No
CHECK the affected seat cushion or backrest for correct installation of the climate controlled seat components (TED (Thermo-Electric Device) , manifold, plenum, air ducts and foam pad). CHECK for airflow restrictions (TED (Thermo-Electric Device) inlets and outlets, TED (Thermo-Electric Device) -to-manifold or plenum connections, filters and ducts) and REPAIR as needed. CHECK for an intermittent wiring fault. REPAIR as needed. REPEAT the self-test. CLEAR the DTCs.
AO5 CHECK FOR CORRECT TED (Thermo-Electric Device) INSTALLATION AND FOR CRUSHED FOAM
- Ignition OFF.
- Remove the seat. Refer to Seat- Front .
- Remove the seat cushion trim cover. Refer to Seat Cushion Cover- Front .
- Inspect the seat cushion for the following:
- 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 the foam pad and manifold OK?
Yes
GO to AO6.
No
CORRECTLY install the cushion TED (Thermo-Electric Device) or INSTALL a new seat cushion foam pad and/or climate controlled seat manifold. REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable. REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
AO6 CHECK THE BACKREST TED (Thermo-Electric Device) GROUND CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Position the driver seat in the vehicle and connect the seat-to-floor connectors.
- Disconnect: Driver Seat Side Air Bag Module C327.
- Disconnect: Passenger Seat Side Air Bag Module C313.
- Disconnect: DCSM (Dual Climate Controlled Seat Module) C3305A.
- WARNING: Make sure no one is in the vehicle and there is nothing blocking or placed in front of any air bag module when the battery is connected. Failure to follow these instructions may result in serious personal injury in the event of an accidental deployment.
Connect the battery ground cable.
- Ignition ON.
- Measure the voltage between DCSM (Dual Climate Controlled Seat Module) C3305A-K, circuit RHS01 (WH/VT), harness side and ground.
Is any voltage present?
Yes
REPAIR the circuit. REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C327. CONNECT passenger seat side air bag module C313. REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
No
GO to AO7.
AO7 CHECK THE BACKREST TED (Thermo-Electric Device) FEED CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3305A-J, circuit CHS01 (GY/VT), harness side and ground.
Is the resistance greater than 10,000 ohms?
Yes
GO to AO8.
No
REPAIR the circuit. REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C327. CONNECT passenger seat side air bag module C313. REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
AO8 CHECK THE RESISTANCE OF THE BACKREST TED (Thermo-Electric Device) AND WIRING
- Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3305A-J, circuit CHS01 (GY/VT), harness side and DCSM (Dual Climate Controlled Seat Module) C3305A-K, circuit RHS01 (WH/VT), harness side.
Is the resistance between 0.9 and 10 ohms?
Yes
GO to AO10.
No
GO to AO9.
AO9 CHECK THE RESISTANCE OF THE BACKREST TED (Thermo-Electric Device)
- Disconnect: Backrest TED (Thermo-Electric Device) C3310.
- Measure the resistance between backrest TED (Thermo-Electric Device) C3310 pin 1 and pin 3, component side.
Is the resistance between 0.9 and 10 ohms?
Yes
REPAIR circuit CHS01 (GY/VT) or RHS01 (WH/VT) for an open. REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C327. CONNECT passenger seat side air bag module C313. REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
No
INSTALL a new backrest TED (Thermo-Electric Device). REFER to Seat Backrest Thermo-Electric Device . REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C327. CONNECT passenger seat side air bag module C313. REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
AO10 CHECK THE BLOWER MOTOR FEED AND SPEED CONTROL CIRCUITS FOR A SHORT TO VOLTAGE
- Disconnect: DCSM (Dual Climate Controlled Seat Module) C3305C.
- Ignition ON.
- Measure the voltage between:
- DCSM (Dual Climate Controlled Seat Module) C3305C-16, circuit CHS03 (GN/BN), harness side and ground.
- DCSM (Dual Climate Controlled Seat Module) C3305C-11, circuit VHS18 (BN/GN), harness side and ground.
Is voltage present on either circuit?
Yes
GO to AO11.
No
REPAIR the circuit(s). REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C327. CONNECT passenger seat side air bag module C313. REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
AO11 CHECK THE BLOWER MOTOR FEED AND SPEED CONTROL CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between:
- DCSM (Dual Climate Controlled Seat Module) C3305C-16, circuit CHS03 (GN/BN), harness side and ground.
- DCSM (Dual Climate Controlled Seat Module) C3305C-11, circuit VHS18 (BN/GN), harness side and ground.
Are the resistances greater than 10,000 ohms?
Yes
GO to AO12.
No
REPAIR the circuit(s). REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C327. CONNECT passenger seat side air bag module C313. REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
AO12 CHECK THE BLOWER MOTOR AND WIRING
- NOTE: The ohmmeter must be connected with the positive lead to DCSM (Dual Climate Controlled Seat Module) C3305C-16, circuit CHS03 (GN/BN) and the negative lead to DCSM (Dual Climate Controlled Seat Module) C3305C-15, circuit RHS03 (GY/OG) when measuring. Ohmmeter leads incorrectly connected will result in false readings and lead to incorrect identification of components that are not faulty.
Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3305C-16, circuit CHS03 (GN/BN), harness side and DCSM (Dual Climate Controlled Seat Module) C3305C-15, circuit RHS03 (GY/OG), harness side.
Is the resistance between 4,000 and 10,000 ohms?
Yes
GO to AO14.
No
GO to AO13.
AO13 CHECK THE BLOWER MOTOR RESISTANCE
- Disconnect: Cushion TED (Thermo-Electric Device) C3300.
- NOTE: The ohmmeter must be connected with the positive lead to pin 2 and the negative lead to pin 4 when measuring. Ohmmeter leads incorrectly connected will result in false readings and lead to incorrect identification of components that are not faulty.
Measure the resistance between cushion TED (Thermo-Electric Device) C3300 pin 2 and pin 4, component side.
Is the resistance between 4,000 and 10,000 ohms?
Yes
REPAIR the circuit(s). REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C327. CONNECT passenger seat side air bag module C313. REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
No
INSTALL a new cushion TED (Thermo-Electric Device). REFER to Seat Cushion Thermo-Electric Device . REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C327. CONNECT passenger seat side air bag module C313. REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
AO14 CHECK THE BLOWER MOTOR SPEED CONTROL AND CIRCUIT RESISTANCE
- NOTE: The ohmmeter must be connected with the positive lead to C3305C-11, circuit VHS18 (BN/GN), harness side and the negative lead to C3305C-15, circuit RHS03 (GY/OG), harness side when measuring. Ohmmeter leads incorrectly connected will result in false readings and lead to incorrect identification of components that are not faulty.
Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3305C-11, circuit VHS18 (BN/GN), harness side and DCSM (Dual Climate Controlled Seat Module) C3305C-15, circuit RHS03 (GY/OG), harness side.
Is the resistance between 240 kohms and 4 megohms?
Yes
GO to AO16.
No
GO to AO15.
AO15 CHECK THE BLOWER MOTOR SPEED CONTROL RESISTANCE
- Disconnect: Cushion TED (Thermo-Electric Device) C3300.
- 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 will result in false readings and lead to incorrect identification of components that are not faulty.
Measure the resistance between cushion TED (Thermo-Electric Device) C3300 pin 7 and pin 4, component side.
Is the resistance between 240 kohms and 4 megohms?
Yes
REPAIR the circuit(s). REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C327. CONNECT passenger seat side air bag module C313. REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
No
INSTALL a new cushion TED (Thermo-Electric Device). REFER to Seat Cushion Thermo-Electric Device . REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C327. CONNECT passenger seat side air bag module C313. REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.