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Pinpoint Test AW: DTC B272F




Seats

Pinpoint Tests

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. Diagrams By Number

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, diagnostic testing can be carried out with the ignition switch ON and the engine OFF. The system receives voltage from Battery Junction Box (BJB) fuse 16 (30A) supplying battery voltage on circuit SBB16 (VT/RD) into DCSM C3036a pins E and F. If voltage is disconnected from either pin E or F of DCSM C3036a with the connection remaining on the other circuit, both seats will remain operational because the circuits are connected internally in the DCSM. However, if a fault occurs setting a DTC specific to either climate controlled seat, only the affected seat will be disabled by the DCSM and the other will remain operational.

Each driver and front passenger seat cushion and backrest are equipped with a Thermo-Electric Device (TED) assembly that includes a seat blower (fan motor, serviced as an assembly with the TED). Cabin air is drawn through the blower and distributed to each of the TED modules located in the seat cushion and backrest. The TEDs 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 uses a set of flexible algorithms to control the heating/cooling modes and the blower speed dependant on the HVAC module 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
- DCSM



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.

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AW1 CHECK DCSM PASSENGER TED HEAT MODE (TED_HEAT_P) PID


- Access the cushion and backrest TEDs and remove the filters to watch the TED fans.
- Connect the scan tool.
- Enter the following diagnostic mode on the scan tool: DataLogger - DCSM PID TED_HEAT_P.
- NOTE: The DCSM 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 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.

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AW2 CHECK FOR AN INTERMITTENT CONNECTION AT THE DCSM


- Ignition OFF.
- Disconnect: DCSM C3036c.
- Connect: DCSM C3036c.
- 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 C3036c and REPAIR the circuit. REPEAT the self-test. CLEAR the DTCs.

No
GO to AW3.

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AW3 CHECK FOR AN INTERMITTENT CONNECTION AT THE CUSHION TED


- Ignition OFF.
- Disconnect: Cushion TED C3328.
- Connect: Cushion TED C3328.
- 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 C3328 and REPAIR the circuit. REPEAT the self-test. CLEAR the DTCs.

No
GO to AW4.

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AW4 CHECK FOR AN INTERMITTENT CONNECTION AT THE BACKREST TED


- Ignition OFF.
- Disconnect: Backrest TED C3326.
- Connect: Backrest TED C3326.
- 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 C3326 and REPAIR the circuit. REPEAT the self-test. CLEAR the DTCs.

No
GO to AW5.

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AW5 CHECK BLOWER CIRCUIT CHS08 (BN/YE) FOR A SHORT TO VOLTAGE


- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of Restraint Systems.
- Disconnect: Passenger Seat Side Air Bag C327.
- Disconnect: DCSM C3036c.
- Disconnect: Cushion TED C3328.
- Disconnect: Backrest TED C3326.
- 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. Refer to Battery.
- Ignition ON.
- Measure the voltage between DCSM C3036c-8, circuit CHS08 (BN/YE), 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 passenger seat side air bag module C327.

REPOWER the SRS. REFER to Restraint Systems.

No
GO to AW6.

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AW6 CHECK CUSHION TED BLOWER CIRCUITS CHS08 (BN/YE) AND RHS08 (VT/WH) FOR AN OPEN


- Measure the resistance between:
- DCSM C3036c-8, circuit CHS08 (BN/YE), harness side and cushion TED C3328-2, circuit CHS08 (BN/YE), harness side.
- DCSM C3036c-7, circuit RHS08 (VT/WH), harness side and cushion TED C3328-4, circuit RHS08 (VT/WH), harness side.




- Are the resistances less than 5 ohms?

Yes
GO to AW7.

No
REPAIR the affected circuit. REPEAT the self-test. CLEAR the DTCs.

DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C327.

REPOWER the SRS. REFER to Restraint Systems.

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AW7 CHECK BACKREST TED BLOWER CIRCUITS CHS08 (BN/YE) AND RHS08 (VT/WH) FOR AN OPEN


- Measure the resistance between:
- DCSM C3036c-8, circuit CHS08 (BN/YE), harness side and backrest TED C3326-2, circuit CHS08 (BN/YE), harness side.
- DCSM C3036c-7, circuit RHS08 (VT/WH), harness side and backrest TED C3326-4, circuit RHS08 (VT/WH), harness side.




- Are the resistances less than 5 ohms?

Yes
GO to AW8.

No
REPAIR the affected circuit. REPEAT the self-test. CLEAR the DTCs.

DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C327.

REPOWER the SRS. REFER to Restraint Systems.

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AW8 CHECK THE 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 cushion TED C3328 pin 2 and pin 4, component side and between backrest TED C3326 pin 2 and pin 4, component side.




- Are the resistances between 4,000 ohms and 10,000 ohms?

Yes
INSTALL a new DCSM. REFER to Dual Climate Controlled Seat Module (DCSM) Dual Climate Controlled Seat Module (DCSM). REPEAT the self-test. CLEAR the DTCs.

DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C327.

REPOWER the SRS. REFER to Restraint Systems.

No
If the resistance of the cushion TED was not between 4,000 ohms and 10,000 ohms, INSTALL a new cushion TED. REFER to Seat Cushion Thermo-Electric Device Seat Cushion Thermo-Electric Device. REPEAT the self-test. CLEAR the DTCs.

If the resistance of the backrest TED was not between 4,000 ohms and 10,000 ohms, INSTALL a new backrest TED. REFER to Seat Backrest Thermo-Electric Device Seat Backrest Thermo-Electric Device. REPEAT the self-test. CLEAR the DTCs.

DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C327.

REPOWER the SRS. REFER to Restraint Systems.

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