Part 2

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)

AO16 CHECK THE THERMISTOR FEED 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: Driver Seat Side Air Bag Module C327.

- Disconnect: Passenger Seat Side Air Bag Module C313.

- Disconnect: DCSM (Dual Climate Controlled Seat Module) C3305B.

- 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) C3305B-7, circuit VHS26 (VT), harness side and ground.

Is the resistance greater than 10,000 ohms?

Yes
GO to AO18.

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.

AO18 CHECK THE TED (Thermo-Electric Device) THERMISTOR AND WIRING RESISTANCE AT THE DCSM (Dual Climate Controlled Seat Module)

- Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3305B-7, circuit VHS26 (VT), harness side and DCSM (Dual Climate Controlled Seat Module) C3305B-8, circuit RHS05 (YE/VT), harness side. Note the ambient temperature and compare result to the following table:

Temperature Resistance 0-10°C (32-50°F) 2,782-1,663 ohms 10-20°C (50-68°F) 1,837-1,140 ohms 20-30°C (68-86°F) 1,260-806 ohms 30-40°C (86-104°F) 893-570 ohms 40-50°C (104-122°F) 630-428 ohms

Is the resistance within the limits indicated?

Yes
INSTALL a new DCSM (Dual Climate Controlled Seat Module). REFER to Dual Climate Controlled Seat Module (DCSM) . 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 AO19.

AO19 CHECK THE TED (Thermo-Electric Device) THERMISTOR RESISTANCE

- Disconnect: Cushion TED (Thermo-Electric Device) C3300.

- Measure the resistance between cushion TED (Thermo-Electric Device) pin 5 and pin 8, component side. Note the ambient temperature and compare result to the following table:

Temperature Resistance 0-10°C (32-50°F) 2,782-1,663 ohms 10-20°C (50-68°F) 1,837-1,140 ohms 20-30°C (68-86°F) 1,260-806 ohms 30-40°C (86-104°F) 893-570 ohms 40-50°C (104-122°F) 630-428 ohms

Is the resistance within the limits indicated?

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.

AO20 CHECK FOR CORRECT TED (Thermo-Electric Device) INSTALLATION AND FOR CRUSHED FOAM

- Ignition OFF.

- Remove the seat. Refer to Seat- Front .

- Remove the seat backrest trim cover. Refer to Seat Backrest- Front .

- Inspect the seat backrest for the following:
- 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 the foam pad and manifold OK?

Yes
GO to AO21.

No
CORRECTLY install the backrest TED (Thermo-Electric Device) 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 (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AO21 CHECK THE CUSHION 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.

- 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: Driver Seat Side Air Bag 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-H, circuit RHS02 (BU/OG), harness side and ground.

Is the resistance greater than 10,000 ohms?

Yes
GO to AO23.

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.

AO23 CHECK THE RESISTANCE OF THE CUSHION TED (Thermo-Electric Device) AND WIRING

- Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3305A-G circuit CHS02 (YE/BU), harness side and DCSM (Dual Climate Controlled Seat Module) C3305A-H, circuit RHS02 (BU/OG), harness side.

Is the resistance between 0.9 and 10 ohms?

Yes
GO to AO25.

No
GO to AO24.

AO24 CHECK THE CUSHION TED (Thermo-Electric Device) RESISTANCE

- Disconnect: Cushion TED (Thermo-Electric Device) C3300.

- Measure the resistance between cushion TED (Thermo-Electric Device) C3300 pin 1 and pin 3, component side.

Is the resistance between 0.9 and 10 ohms?

Yes
REPAIR circuit CHS02 (YE/BU) or RHS02 (BU/OG) 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 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.

AO25 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-12, circuit VHS16 (BU/GN), 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 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 AO26.

AO26 CHECK THE BLOWER MOTOR AND SPEED CONTROL FEED 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-12, circuit VHS16 (BU/GN), harness side and ground.

Are the resistances greater than 10,000 ohms?

Yes
GO to AO27.

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.

AO27 CHECK THE BLOWER MOTOR AND WIRING RESISTANCE

- 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 AO29.

No
GO to AO28.

AO28 CHECK THE BLOWER MOTOR RESISTANCE

- Disconnect: Backrest TED (Thermo-Electric Device) C3310.

- 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 backrest TED (Thermo-Electric Device) C3310 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 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.

AO29 CHECK THE BLOWER MOTOR SPEED CONTROL AND CIRCUIT RESISTANCE

- NOTE: The ohmmeter must be connected with the positive lead to C3305C-12, circuit VHS16 (BU/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-12, circuit VHS16 (BU/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 AO31.

No
GO to AO30.

AO30 CHECK THE BLOWER MOTOR SPEED CONTROL RESISTANCE

- Disconnect: Backrest TED (Thermo-Electric Device) C3310.

- 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 backrest TED (Thermo-Electric Device) C3310 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 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.

AO31 CHECK THE THERMISTOR FEED CIRCUIT FOR A SHORT TO VOLTAGE

- Disconnect: DCSM (Dual Climate Controlled Seat Module) C3305B.

- Ignition ON.

- Measure the voltage between DCSM (Dual Climate Controlled Seat Module) C3305B-9, circuit VHS35 (VT/OG), 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 AO32.

AO32 CHECK THE THERMISTOR FEED CIRCUIT FOR A SHORT TO GROUND

- 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: Driver Seat Side Air Bag Module C327.

- Disconnect: Passenger Seat Side Air Bag Module C313.

- Disconnect: DCSM (Dual Climate Controlled Seat Module) C3305B.

- Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3305B-9, circuit VHS35 (VT/OG), harness side and ground.

Is the resistance greater than 10,000 ohms?

Yes
GO to AO33.

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.

AO33 CHECK THE TED (Thermo-Electric Device) THERMISTOR AND WIRING RESISTANCE

- Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3305B-9, circuit VHS35 (VT/OG), harness side and DCSM (Dual Climate Controlled Seat Module) C3305B-10, circuit RHS15 (GY/BN), harness side. Note the ambient temperature and compare result to the following table:

Temperature Resistance 0-10°C (32-50°F) 2,782-1,663 ohms 10-20°C (50-68°F) 1,837-1,140 ohms 20-30°C (68-86°F) 1,260-806 ohms 30-40°C (86-104°F) 893-570 ohms 40-50°C (104-122°F) 630-428 ohms

Is the resistance within the limits indicated?

Yes
INSTALL a new DCSM (Dual Climate Controlled Seat Module). REFER to Dual Climate Controlled Seat Module (DCSM) . 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 AO34.

AO34 CHECK THE TED (Thermo-Electric Device) THERMISTOR RESISTANCE

- Disconnect: Backrest TED (Thermo-Electric Device) C3310.

- Measure the resistance between backrest TED (Thermo-Electric Device) pin 5 and pin 8, component side. Note the ambient temperature and compare result to the following table:

Temperature Resistance 0-10°C (32-50°F) 2,782-1,663 ohms 10-20°C (50-68°F) 1,837-1,140 ohms 20-30°C (68-86°F) 1,260-806 ohms 30-40°C (86-104°F) 893-570 ohms 40-50°C (104-122°F) 630-428 ohms