B272F
Seats
Pinpoint Test AW: DTC B272F
NOTE: This DTC sets for an open or short to voltage. See DTC setting description below.
Refer to Wiring Diagram Set 119, Climate Controlled Seats for schematic and connector information Electrical Diagrams.
Normal Operation
Both the driver and front passenger climate controlled seats are independently controlled electronically by the Dual Climate Controlled Seat Module (DCSM) mounted to the bottom of the passenger seat cushion. The climate controlled seat system only operates with the engine running, however, if using a scan tool to command the DCSM (Dual Climate Controlled Seat Module), diagnostic testing can be carried out with the ignition ON engine OFF. The system receives voltage from Battery Junction Box (BJB) fuse 67 (40A) feeding battery voltage on circuit SBB08 (VT/RD) into DCSM (Dual Climate Controlled Seat Module) C3265A pins E and F. If voltage is disconnected from either pin E or F of DCSM (Dual Climate Controlled Seat Module) C3265A with the voltage connection remaining on the other circuit, both seats will remain operational because the voltage feed circuits are connected internally in the DCSM (Dual Climate Controlled Seat Module). However, if a fault occurs setting a DTC specific to either climate controlled seat, only the affected seat will be disabled by the module.
Each driver and front passenger 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, each driver and front passenger 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 climate controlled seat switch settings.
- DTC B272F (Passenger Ignition Run/Blower Circuit Short to Ground)- This DTC is set if the blower voltage or ground circuit opens to both backrest and cushion blowers or if both blower voltage circuits short to voltage. Only one blower voltage circuit needs to be open for the DTC to be set if battery voltage is less than 12 volts.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- HVAC module
- Backrest or cushion TED (Thermo-Electric Device)
- DCSM (Dual Climate Controlled Seat Module)
PINPOINT TEST AW : DTC B272F
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: The air bag warning indicator illuminates when the correct Restraints Control Module (RCM) fuse is removed and the ignition is ON.
NOTE: The Supplemental Restraint System (SRS) must be fully operational and free of faults before releasing the vehicle to the customer.
AW1 CHECK DCSM (Dual Climate Controlled Seat Module) PASSENGER TED (Thermo-Electric Device) HEAT MODE (TED_HEAT_P) PID
- Access the cushion and backrest TEDs (Thermo-Electric Devices) and remove the filters to watch the TED (Thermo-Electric Device) fans.
- Enter the following diagnostic mode on the scan tool: DataLogger- DCSM (Dual Climate Controlled Seat Module)- PID TED_HEAT_P.
- NOTE: The DCSM (Dual Climate Controlled Seat Module) active command TED_HEAT_P is limited to 15 seconds in the ON state.
Operate the climate controlled seat using the active command while monitoring the cushion and backrest TEDs (Thermo-Electric Devices) for fan movement.
Did both fans turn on?
Yes
CARRY OUT the network test. If DTCs are retrieved from the HVAC module, REFER to Body Control Systems. If no DTCs are retrieved, CARRY OUT the HVAC Module Cold Boot Process in the Diagnosis and Testing portion of Heating and Air Conditioning. Testing and Inspection
No
GO to AW2.
AW2 CHECK FOR AN INTERMITTENT CONNECTION AT THE DCSM (Dual Climate Controlled Seat Module)
- Ignition OFF.
- Disconnect: DCSM (Dual Climate Controlled Seat Module) C3265C.
- Connect: DCSM (Dual Climate Controlled Seat Module) C3265C.
- With the engine running and using the switches on the HVAC module, turn the passenger climate controlled seat system on while monitoring the cushion and backrest fans for movement.
- If there is fan movement, run the passenger climate controlled seat system for 2 minutes.
Did the climate controlled seat operate correctly?
Yes
The fault is intermittent. CHECK for causes of the intermittent fault at C3265C and REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
No
GO to AW3.
AW3 CHECK FOR AN INTERMITTENT CONNECTION AT THE CUSHION TED (Thermo-Electric Device)
- Ignition OFF.
- Disconnect: Cushion TED (Thermo-Electric Device) C3040.
- Connect: Cushion TED (Thermo-Electric Device) C3040.
- With the engine running and using the switches on the HVAC module, turn the passenger climate controlled seat system on while monitoring the cushion and backrest fans for movement.
- If there is fan movement, run the passenger climate controlled seat system for 2 minutes.
Did the climate controlled seat operate correctly?
Yes
The fault is intermittent. CHECK for causes of the intermittent fault at C3040 and REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
No
GO to AW4.
AW4 CHECK FOR AN INTERMITTENT CONNECTION AT THE BACKREST TED (Thermo-Electric Device)
- Ignition OFF.
- Disconnect: Backrest TED (Thermo-Electric Device) C3039 (10-Way Power Seat) or C3316 (6-Way Power Seat).
- Connect: Backrest TED (Thermo-Electric Device) C3039 (10-Way Power Seat) or C3316 (6-Way Power Seat).
- With the engine running and using the switches on the HVAC module, turn the passenger climate controlled seat system on while monitoring the cushion and backrest fans for movement.
- If there is fan movement, run the passenger climate controlled seat system for 2 minutes.
Did the climate controlled seat operate correctly?
Yes
The fault is intermittent. CHECK for causes of the intermittent fault at C3039 (10-way power seat) or C3316 (6-way power seat) and REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
No
GO to AW5.
AW5 CHECK THE BLOWER CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Depower the SRS (Supplemental Restraint System). Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of Restraints and Safety Systems &/or Air Bag Systems.
- Disconnect: Passenger Seat Safety Belt Buckle Pretensioner C3050.
- Disconnect: Passenger Seat Side Air Bag C3052.
- Disconnect: DCSM (Dual Climate Controlled Seat Module) C3265C.
- Disconnect: Cushion TED (Thermo-Electric Device) C3040.
- Disconnect: Backrest TED (Thermo-Electric Device) C3039 (10-Way Power Seat) or C3316 (6-Way Power Seat).
- 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) C3265C-8, circuit CHS14 (GN), harness side and ground.
Is any voltage present?
Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle pretensioner C3050. CONNECT passenger seat side air bag module C3052.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
No
GO to AW6.
AW6 CHECK THE CUSHION TED (Thermo-Electric Device) BLOWER CIRCUITS FOR AN OPEN
- Measure the resistance between:
- DCSM (Dual Climate Controlled Seat Module) C3265C-8, circuit CHS14 (GN), harness side and cushion TED (Thermo-Electric Device) C3040-2, circuit CHS14 (GN), harness side.
- DCSM (Dual Climate Controlled Seat Module) C3265C-7, circuit CHS08 (BN/YE), harness side and cushion TED (Thermo-Electric Device) C3040-4, circuit CHS08 (BN/YE), harness side.
Are the resistances less than 5 ohms?
Yes
GO to AW7.
No
REPAIR the circuit(s). CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle pretensioner C3050. CONNECT passenger seat side air bag module C3052.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
AW7 CHECK THE BACKREST TED (Thermo-Electric Device) BLOWER CIRCUITS FOR AN OPEN
- For 6-way power seat, measure the resistance between:
- DCSM (Dual Climate Controlled Seat Module) C3265C-8, circuit CHS14 (GN), harness side and backrest TED (Thermo-Electric Device) C3316-2, circuit CHS14 (GN), harness side.
- DCSM (Dual Climate Controlled Seat Module) C3265C-7, circuit CHS08 (BN/YE), harness side and backrest TED (Thermo-Electric Device) C3316-4, circuit CHS08 (BN/YE), harness side.
- For 10-way power seat, measure the resistance between:
- DCSM (Dual Climate Controlled Seat Module) C3265C-8, circuit CHS14 (GN), harness side and backrest TED (Thermo-Electric Device) C3039-2, circuit CHS13 (VT/BN), harness side.
- DCSM (Dual Climate Controlled Seat Module) C3265C-7, circuit CHS08 (BN/YE), harness side and backrest TED (Thermo-Electric Device) C3039-4, circuit CHS03 (GN/BN), harness side.
Are the resistances less than 5 ohms?
Yes
GO to AW8.
No
REPAIR the circuit(s). CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle pretensioner C3050. CONNECT passenger seat side air bag module C3052.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
AW8 CHECK BLOWER RESISTANCE
- NOTICE: 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:
- backrest TED (Thermo-Electric Device) C3039 (10-way power seat) or C3316 (6-way power seat) pin 2 and pin 4, component side.
- cushion TED (Thermo-Electric Device) C3040 pin 2 and pin 4, component side.
Are the resistances between 4,000 ohms and 10,000 ohms?
Yes
INSTALL a new DCSM (Dual Climate Controlled Seat Module). REFER to Dual Climate Controlled Seat Module (DCSM) . CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle pretensioner C3050. CONNECT passenger seat side air bag module C3052.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
No
If the resistance of the cushion TED (Thermo-Electric Device) was not between 4,000 and 10,000 ohms, INSTALL a new cushion TED (Thermo-Electric Device). REFER to Seat Cushion Thermo-Electric Device . CLEAR the DTCs. REPEAT the self-test.
If the resistance of the backrest TED (Thermo-Electric Device) was not between 4,000 and 10,000 ohms, INSTALL a new backrest TED (Thermo-Electric Device). REFER to Seat Backrest Thermo-Electric Device . CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle pretensioner C3050. CONNECT passenger seat side air bag module C3052.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.