Part 2

Seats

Pinpoint Test AM: DTC B272D

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 (Dual Climate Controlled Seat Module), diagnostic testing can be carried out with the ignition ON. The system receives voltage from Battery Junction Box (BJB) fuse 22 (30A) supplying voltage into DCSM (Dual Climate Controlled Seat Module) C3265a pins E and F, circuit CBX01 (GN/RD). If voltage is disconnected from either pin E or F of DCSM (Dual Climate Controlled Seat Module) C3265a both seats will remain operational because the voltage supply 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 DCSM (Dual Climate Controlled Seat Module).

The 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 (Thermo-Electric Device)). Cabin air is drawn through the blower and distributed to each of the TED (Thermo-Electric Device) modules. 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 B272D (Passenger Differential Temperature Fault)- If there is a temperature differential between the passenger 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 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 (Dual Climate Controlled Seat Module) will shut down the passenger 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 AM : DTC B272D

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.

AM17 CHECK THERMISTOR CIRCUIT FOR A SHORT TO GROUND

- Ignition OFF.

- Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3265B-2, circuit VHS27 (WH/OG), harness side and ground.

Is the resistance greater than 10,000 volts?

Yes
GO to AM18.

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

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AM18 CHECK THE TED (Thermo-Electric Device) THERMISTOR AND WIRING RESISTANCE

- Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3265B-2, circuit VHS27 (WH/OG), harness side and DCSM (Dual Climate Controlled Seat Module) C3265B-3, circuit RHS10 (BU/OG), 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) . CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

No
GO to AM19.

AM19 CHECK THE TED (Thermo-Electric Device) THERMISTOR RESISTANCE

- Disconnect: Cushion TED (Thermo-Electric Device) C3040.

- 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). CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

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 . CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AM20 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 Cover- 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 AM21.

No
Correctly INSTALL the backrest TED (Thermo-Electric Device) or INSTALL a new seat backrest foam pad and/or climate controlled seat manifold. REFER to Seat Backrest Thermo-Electric Device . CLEAR the DTCs. REPEAT the self-test.

INSTALL the seat. REFER to Seat - Front .

CLEAR the DTCs. REPEAT the self-test.

AM21 CHECK CUSHION TED (Thermo-Electric Device) CIRCUIT 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 (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 Side Air Bag C3133.

- Disconnect: Passenger Safety Belt Buckle Pretensioner C3066.

- Disconnect: DCSM (Dual Climate Controlled Seat Module) C3265a.

- 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) C3265A-B, circuit RHS07 (BU), harness side and ground.

Is the resistance greater than 10,000 ohms?

Yes
GO to AM23.

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

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AM23 CHECK THE CUSHION TED (Thermo-Electric Device) AND WIRING RESISTANCE

- Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3265A-A circuit CHS07 (GY/BU), harness side and DCSM (Dual Climate Controlled Seat Module) C3265A-B, circuit RHS07 (BU), harness side.

Is the resistance between 0.9 and 10 ohms?

Yes
GO to AM25.

No
GO to AM24.

AM24 CHECK THE CUSHION TED (Thermo-Electric Device) RESISTANCE

- Disconnect: Cushion TED (Thermo-Electric Device) C3040.

- Measure the resistance between cushion TED (Thermo-Electric Device) C3040 pin 1 and pin 3, component side.

Is the resistance between 0.9 and 10 ohms?

Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

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 . CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AM25 CHECK BLOWER CIRCUIT AND SPEED CONTROL CIRCUIT FOR A SHORT TO VOLTAGE

- Disconnect: DCSM (Dual Climate Controlled Seat Module) C3265c.

- Ignition ON.

- Measure the voltage between:
- DCSM (Dual Climate Controlled Seat Module) C3265C-8, circuit CHS08 (BN/YE), harness side and ground.

- DCSM (Dual Climate Controlled Seat Module) C3265C-4, circuit VHS21 (BU/WH), harness side and ground.

Is voltage present on either circuit?

Yes
REPAIR the circuit(s). CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

No
GO to AM26.

AM26 CHECK BLOWER AND SPEED CONTROL CIRCUITS FOR A SHORT TO GROUND

- Ignition OFF.

- Measure the resistance between:
- DCSM (Dual Climate Controlled Seat Module) C3265C-8, circuit CHS08 (BN/YE), harness side and ground.

- DCSM (Dual Climate Controlled Seat Module) C3265C-4, circuit VHS21 (BU/WH), harness side and ground.

Are the resistances greater than 10,000 ohms?

Yes
GO to AM27.

No
REPAIR the circuit(s). CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AM27 CHECK THE BLOWER AND WIRING RESISTANCE

- NOTE: The ohmmeter must be connected with the positive lead to DCSM (Dual Climate Controlled Seat Module) C3265C-8, circuit CHS08 (BN/YE) and the negative lead to DCSM (Dual Climate Controlled Seat Module) C3265C-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 the resistance between DCSM (Dual Climate Controlled Seat Module) C3265C-8, circuit CHS08 (BN/YE), harness side and DCSM (Dual Climate Controlled Seat Module) C3265C-7, circuit RHS08 (VT/WH), harness side.

Is the resistance between 4,000 ohms and 10,000 ohms?

Yes
GO to AM29.

No
GO to AM28.

AM28 CHECK THE BLOWER RESISTANCE

- Disconnect: Backrest TED (Thermo-Electric Device) C3039.

- 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) C3039 pin 2 and pin 4, component side.

Is the resistance between 4,000 ohms and 10,000 ohms?

Yes
REPAIR the circuit(s). CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

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 . CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AM29 CHECK THE BLOWER SPEED CONTROL AND CIRCUIT RESISTANCE

- NOTE: The ohmmeter must be connected with the positive lead to C3265C-4, circuit VHS21 (BU/WH), harness side and the negative lead to C3265C-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 the resistance between DCSM (Dual Climate Controlled Seat Module) C3265C-4, circuit VHS21 (BU/WH), harness side and DCSM (Dual Climate Controlled Seat Module) C3265C-7, circuit RHS08 (VT/WH), harness side.

Is the resistance between 240K ohms and 4M ohms?

Yes
GO to AM31.

No
GO to AM30.

AM30 CHECK THE BLOWER SPEED CONTROL RESISTANCE

- Disconnect: Backrest TED (Thermo-Electric Device) C3039.

- 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) C3039 pin 7 and pin 4, component side.

Is the resistance between 240K ohms and 4M ohms?

Yes
REPAIR the circuit(s). CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

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 . CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AM31 CHECK THERMISTOR CIRCUIT FOR A SHORT TO VOLTAGE

- Disconnect: DCSM (Dual Climate Controlled Seat Module) C3265b.

- Ignition ON.

- Measure the voltage between DCSM (Dual Climate Controlled Seat Module) C3265B-4, circuit VHS36 (YE/BU), 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 safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

No
GO to AM32.

AM32 CHECK THERMISTOR 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: Passenger Seat Side Air Bag C3133.

- Disconnect: Passenger Safety Belt Buckle Pretensioner C3066.

- Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3265B-4, circuit VHS36 (YE/BU), harness side and ground.

Is the resistance greater than 10,000 ohms?

Yes
GO to AM33.

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

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AM33 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) C3265B-4, circuit VHS36 (YE/BU), harness side and DCSM (Dual Climate Controlled Seat Module) C3265B-5, circuit RHS20 (GN/BU), 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) . CLEAR the DTCs. REPEAT the self-test.

DISCONNECT the battery ground cable.

CONNECT passenger safety belt buckle pretensioner C3066.

CONNECT passenger seat side air bag module C3133.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

No
GO to AM34.

AM34 CHECK THE TED (Thermo-Electric Device) THERMISTOR RESISTANCE

- Disconnect: Backrest TED (Thermo-Electric Device) C3039.

- 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