AN18-AN34
Seats
Pinpoint Tests
Pinpoint Test AN: DTC B272D
Refer to Wiring Diagram Set 119, Climate Controlled Seats for schematic and connector information. Diagrams By Number
Normal Operation
Climate controlled seats are independently controlled 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 Key ON Engine OFF (KOEO). The system receives voltage from Battery Junction Box (BJB) fuse 12 (30A) supplying battery voltage on circuit SBB12 (GN/RD) into DCSM C3305a pin F. The system also receives voltage from BJB fuse 11 (30A) supplying battery voltage on circuit SBB11 (BU/RD) into DCSM C3305a pin E. If voltage is disconnected from either pin E or F of DCSM C3305a with the voltage connection remaining on the other circuit, both seats will remain operational because the voltage supply 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 module and the other will remain operational.
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). Similarly, the seat backrest is also equipped with its own TED assembly with blower. 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.
A differential fault occurs when the cushion and backrest TEDs on an affected seat are reporting very different temperatures to the DCSM. This may result from an airflow restriction or a circuit fault of either TED area. If a TED and manifold is clear of obstruction and is operational, the other TED and circuitry on the seat should be checked. It is important to note that a TED with a higher temperature may be operating correctly and not the area of concern. The other TED may be indicating a much lower temperature, causing the DTC to set.
- DTC B272D Passenger Differential Temperature Fault - If there is a temperature differential between the passenger backrest and cushion TED of 60°C (108°F) or more for more than 4 seconds, the TED is disconnected or the duct is blocked, this DTC will set. When this happens the first time in a key cycle, the DCSM puts the passenger 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 will shut down the passenger seat system.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Restricted cushion or backrest TED filter
- Crushed or restricted cushion or backrest foam pad
- Crushed or restricted cushion or backrest climate controlled seat manifold
- Cushion or backrest TED assembly
- DCSM
PINPOINT TEST AN: DTC B272D
NOTE: The air bag warning indicator illuminates when the correct Restraints Control Module (RCM) fuse is removed and the ignition switch 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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AN18 CHECK TED THERMISTOR AND WIRING RESISTANCE
- Measure resistance between DCSM C3305b-2, circuit VHS27 (WH/OG), harness side and DCSM C3305b-3, circuit RHS10 (BU/OG), harness side. Note the ambient temperature and compare result to the following table:
- Is resistance within the limits indicated?
Yes
INSTALL a new DCSM and CARRY OUT Programmable Module Installation (PMI). 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 C313. REPOWER the SRS. REFER to Air Bag Systems.
No
GO to AN19.
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AN19 CHECK TED THERMISTOR RESISTANCE
- Disconnect: Cushion TED C3303.
- Measure resistance between cushion TED pin 5 and pin 8, component side. Note the ambient temperature and compare result to the following table:
- Is resistance within the limits indicated?
Yes
REPAIR the circuit(s). REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C313. REPOWER the SRS. REFER to Air Bag Systems.
No
INSTALL a new cushion TED. REFER to Seat Cushion Thermo-Electric Device Seat Cushion Thermo-Electric Device. REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C313. REPOWER the SRS. REFER to Air Bag Systems.
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AN20 CHECK FOR CORRECT TED INSTALLATION AND FOR CRUSHED FOAM
- Ignition OFF.
- Remove the seat. Refer to Seat - Front Seat - Front.
- Remove the seat backrest trim cover. Refer to Seat Backrest Cover - Front, Without Fold Flat Seat Backrest Cover - Front, Without Fold Flat.
- Inspect the seat backrest for the following:
- Is the backrest blower obstructed?
- Is the blower filter restricted or plugged?
- Is the TED correctly installed?
- Is the seat backrest foam pad crushed or restricted?
- Is the climate controlled seat manifold crushed or restricted?
- Is the TED correctly installed and the foam pad and manifold OK?
Yes
GO to AN21.
No
Correctly INSTALL the backrest TED or INSTALL a new seat backrest foam pad and/or climate controlled seat manifold. REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable. REPOWER the SRS. REFER to Air Bag Systems.
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AN21 CHECK CUSHION TED CIRCUIT RHS07 (BU) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Position the front passenger seat in the vehicle and connect the seat-to-floor connectors.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of Air Bag Systems.
- Disconnect: Passenger Seat Side Air Bag C313.
- Disconnect: DCSM 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. Refer to Battery.
- Ignition ON.
- Measure voltage between DCSM C3305a-B, circuit RHS07 (BU), 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 C313. REPOWER the SRS. REFER to Air Bag Systems.
No
GO to AN22.
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AN22 CHECK CUSHION TED CIRCUIT CHS07 (GY/BU) FOR A SHORT TO GROUND
- Ignition OFF.
- Measure resistance between DCSM C3305a-A, circuit CHS07 (GY/BU), harness side and ground.
- Is resistance greater than 10,000 ohms?
Yes
GO to AN23.
No
REPAIR the circuit. REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C313. REPOWER the SRS. REFER to Air Bag Systems.
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AN23 CHECK CUSHION TED AND WIRING RESISTANCE
- Measure resistance between DCSM C3305a-A circuit CHS07 (GY/BU), harness side and DCSM C3305a-B, circuit RHS07 (BU), harness side.
- Is resistance between 0.9 and 10 ohms?
Yes
GO to AN25.
No
GO to AN24.
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AN24 CHECK CUSHION TED RESISTANCE
- Disconnect: Cushion TED C3303.
- Measure resistance between cushion TED C3303 pin 1 and pin 3, component side.
- Is resistance between 0.9 and 10 ohms?
Yes
REPAIR the circuit. REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C313. REPOWER the SRS. REFER to Air Bag Systems.
No
INSTALL a new cushion TED. REFER to Seat Cushion Thermo-Electric Device Seat Cushion Thermo-Electric Device. REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C313. REPOWER the SRS. REFER to Air Bag Systems.
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AN25 CHECK BLOWER CIRCUIT CHS08 (BN/YE) AND SPEED CONTROL CIRCUIT VHS21 (BU/WH) FOR A SHORT TO VOLTAGE
- Disconnect: DCSM C3305c.
- Ignition ON.
- Measure voltage between:
- DCSM C3305c-8, circuit CHS08 (BN/YE), harness side and ground.
- DCSM C3305c-4, circuit VHS21 (BU/WH), harness side and ground.
- Is voltage present on either circuit?
Yes
REPAIR the circuit(s). REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C313. REPOWER the SRS. REFER to Air Bag Systems.
No
GO to AN26.
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AN26 CHECK BLOWER AND SPEED CONTROL CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Measure resistance between:
- DCSM C3305c-8, circuit CHS08 (BN/YE), harness side and ground.
- DCSM C3305c-4, circuit VHS21 (BU/WH), harness side and ground.
- Are resistances greater than 10,000 ohms?
Yes
GO to AN27.
No
REPAIR the circuit(s). REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C313. REPOWER the SRS. REFER to Air Bag Systems.
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AN27 CHECK BLOWER AND WIRING RESISTANCE
- NOTE: The ohmmeter must be connected with the positive lead to DCSM C3305c-8, circuit CHS08 (BN/YE) and the negative lead to DCSM C3305c-7, circuit RHS08 (VT/WH) when measuring. Ohmmeter leads incorrectly connected will result in false readings and lead to incorrect identification of components that are not faulty.
- Measure resistance between DCSM C3305c-8, circuit CHS08 (BN/YE), harness side and DCSM C3305c-7, circuit RHS08 (VT/WH), harness side.
- Is resistance between 6K ohms and 9K ohms?
Yes
GO to AN29.
No
GO to AN28.
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AN28 CHECK BLOWER RESISTANCE
- Disconnect: Backrest TED C3311.
- 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 resistance between backrest TED C3311 pin 2 and pin 4, component side.
- Is resistance between 6K ohms and 9K ohms?
Yes
REPAIR the circuit(s). REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C313. REPOWER the SRS. REFER to Air Bag Systems.
No
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 C313. REPOWER the SRS. REFER to Air Bag Systems.
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AN29 CHECK BLOWER SPEED CONTROL AND CIRCUIT RESISTANCE
- NOTE: The ohmmeter must be connected with the positive lead to C3305c-4, circuit VHS21 (BU/WH), harness side and the negative lead to C3305c-7, circuit RHS08 (VT/WH), 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 resistance between DCSM C3305c-4, circuit VHS21 (BU/WH), harness side and DCSM C3305c-7, circuit RHS08 (VT/WH), harness side.
- Is resistance between 290K ohms and 420K ohms?
Yes
GO to AN31.
No
GO to AN30.
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AN30 CHECK BLOWER SPEED CONTROL RESISTANCE
- Disconnect: Backrest TED C3311.
- 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 resistance between backrest TED C3311 pin 7 and pin 4, component side.
- Is resistance between 290K ohms and 420K ohms?
Yes
REPAIR the circuit(s). REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C313. REPOWER the SRS. REFER to Air Bag Systems.
No
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 C313. REPOWER the SRS. REFER to Air Bag Systems.
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AN31 CHECK THERMISTOR CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: DCSM C3305b.
- Ignition ON.
- Measure voltage between DCSM C3305b-4, circuit VHS36 (YE/BU), 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 C313. REPOWER the SRS. REFER to Air Bag Systems.
No
GO to AN32.
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AN32 CHECK THERMISTOR CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of Air Bag Systems.
- Disconnect: Passenger Seat Side Air Bag Module C313.
- Measure resistance between DCSM C3305b-4, circuit VHS36 (YE/BU), harness side and ground.
- Is resistance greater than 10,000 ohms?
Yes
GO to AN33.
No
REPAIR the circuit. REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C313. REPOWER the SRS. REFER to Air Bag Systems.
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AN33 CHECK TED THERMISTOR AND WIRING RESISTANCE AT THE DCSM
- Measure resistance between DCSM C3305b-4, circuit VHS36 (YE/BU), harness side and DCSM C3305b-5, circuit RHS20 (GN/BU), harness side. Note the ambient temperature and compare result to the following table:
- Is resistance within the limits indicated?
Yes
INSTALL a new DCSM and CARRY OUT Programmable Module Installation (PMI). 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 C313. REPOWER the SRS. REFER to Air Bag Systems.
No
GO to AN34.
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AN34 CHECK TED THERMISTOR RESISTANCE
- Disconnect: Backrest TED C3311.
- Measure resistance between backrest TED pin 5 and pin 8, component side. Note the ambient temperature and compare result to the following table:
- Is resistance within the limits indicated?
Yes
REPAIR the circuit(s). REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C313. REPOWER the SRS. REFER to Air Bag Systems.
No
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 C313. REPOWER the SRS. REFER to Air Bag Systems.
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