Steps AG1-AG18
Seats
Pinpoint Tests
Pinpoint Test AG: DTC B272D
Refer to Wiring Diagram Set 119, Climate Controlled Seats for schematic and connector information. 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 switches on the HVAC module. When commanding a heat or cool mode operation in this manner, the climate controlled seat system will only operate in 15-second intervals. Both voltage supply circuits are spliced together internal to the DCSM, 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.
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 is 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 sets. When this happens the first time in a key cycle, the DCSM puts the passenger seat system into recovery mode (see Principles of Operation) Principles of Operation. If the system is able to recover, it functions normally. If the system is able to recover and it occurs a second time in the same key cycle, the DCSM shuts 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 AG: DTC B272D
NOTICE: Use the correct probe adapter(s) from the Flex Probe Kit when taking measurements. Failure to use the correct probe adapter(s) may damage the connector.
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AG1 CHECK THE DCSM FOR DTCs
- Enter the following diagnostic mode on the scan tool: Self Test - DCSM.
- Was DTC B272A or B272B retrieved?
Yes
For DTC B272A, GO to Pinpoint Test AD. For DTC B272B, GO to Pinpoint Test AE. Pinpoint Test AD: DTC B272A Pinpoint Test AE: DTC B272B
No
GO to AG2.
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AG2 MONITOR THE DCSM TED TEMPERATURE PIDs
- Enter the following diagnostic mode on the scan tool: DataLogger - DCSM.
- Passenger cushion thermal electric device (TED) temperature (PCSHTMP)
- Passenger back TED temperature (PBKTMP)
- Driver cushion TED temperature (CSHTEMP)
- Driver back TED temperature (BK_TEMP)
- NOTE: Make sure the temperature of the climate controlled seats has stabilized before monitoring the PIDs. Not allowing stabilization can cause incorrect readings and lead to incorrect identification of components that are not faulty.
- Monitor the TED temperature PIDs with the climate controlled seats OFF. Compare the PIDs of the front passenger seat to those of the driver seat, this can help identify if there is a concern with the front passenger seat cushion or backrest PID readings.
- Are both front passenger seat TED temperature PIDs within 10°C (18°F) of the ambient temperature?
Yes
GO to AG3.
No
If the front passenger seat cushion PID varies 10°C (18°F) or more from ambient temperature, GO to AG16.
If the front passenger seat backrest PID varies 10°C (18°F) or more from ambient temperature, GO to AG32.
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AG3 CONFIRM THE FAULT IS IN THE SEAT CUSHION OR BACKREST
- Ignition OFF.
- Ignition ON.
- NOTE: A crushed seat cushion foam pad or a crushed climate controlled seat manifold may be the cause of the fault. It may be necessary to sit on the seat or place something of reasonable size and weight on the seat to recreate the fault.
- After cycling the ignition and with the engine running, set the passenger seat to high heat (3 indicators illuminated on HVAC module). Allow the seat to heat for at least 15 minutes while monitoring the TED temperature PIDs of the passenger seat.
- Do the passenger seat cushion TED and backrest TED PIDs vary more than 60°C (108°F) from each other?
Yes
If the front passenger seat cushion PID is 60°C (108°F) hotter than the backrest PID, GO to AG5.
If the front passenger seat backrest PID is 60°C (108°F) hotter than the cushion PID, GO to AG20.
No
GO to AG4.
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AG4 CHECK THE TEDs COOLING PERFORMANCE
- Check TEDs cooling performance on the affected seat. Refer to Component Test - Thermo-Electric Device (TED) Cooling Performance. Component Tests and General Diagnostics
- Did the TEDs pass the component test?
Yes
The DTC may have been set by extreme cabin temperatures or excessive sunload on the seat causing the system to enter recovery mode. Occupant size and weight characteristics can also be a factor. CLEAR the DTCs. TEST the system for normal operation. If a concern cannot be found or duplicated, RETURN the vehicle to the customer.
No
CHECK the affected seat cushion or backrest for correct installation of the climate controlled seat components (TED, manifold, plenum, air ducts and foam pad). CHECK for airflow restrictions (TED inlets and outlets, TED-to-manifold or plenum connections, filters and ducts) and REPAIR as needed. CHECK for an intermittent wiring fault. REPAIR as needed. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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AG5 CHECK FOR CORRECT TED INSTALLATION AND FOR CRUSHED FOAM
NOTE: If a seat equipped with a seat mounted side air bag is being serviced, the Supplemental Restraint System (SRS) must be depowered. Refer to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
NOTE: The air bag warning lamp illuminates when the Restraints Control Module (RCM) fuse is removed and the ignition switch is ON. This is normal operation and does not indicate an SRS fault.
NOTE: The SRS must be fully operational and free of faults before releasing the vehicle to the customer.
- Ignition OFF.
- 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.
- For vehicles equipped with seat side air bags, carry out the following:
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
- Disconnect the passenger seat side air bag module C339.
- Connect the battery ground cable. Refer to Battery, Mounting and Cables Battery Disconnect / Connect.
- Remove the passenger seat. Refer to Seat - Front, Bucket Seat Bucket Seat.
- Remove the passenger seat cushion trim cover. Refer to Seat Cushion - Front, Bucket Seat Bucket Seat.
- Inspect the seat cushion for the following:
- Is the cushion blower obstructed?
- Is the blower filter restricted or plugged?
- Is the TED correctly installed?
- Is the seat cushion 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 AG6.
No
Correctly INSTALL the passenger cushion TED or INSTALL a new seat cushion foam pad and/or climate controlled seat manifold. CLEAR the DTCs. REPEAT the self-test.
For vehicles equipped with seat side air bags, DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C339. REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
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AG6 CHECK THE PASSENGER BACKREST TED- CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Position the front passenger seat in the vehicle and connect the seat-to-floor connectors.
- Disconnect: DCSM C3265A.
- Ignition ON.
- Measure the voltage between DCSM C3265A-D, circuit RHS06 (WH), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
For vehicles equipped with seat side air bags, DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C339. REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
No
GO to AG7.
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AG7 CHECK THE PASSENGER BACKREST TED CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between DCSM C3265A-C, circuit CHS06 (BU/BN), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to AG8.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
For vehicles equipped with seat side air bags, DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C339. REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
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AG8 CHECK THE PASSENGER BACKREST TED AND WIRING RESISTANCE
- Measure the resistance between DCSM C3265A-C, circuit CHS06 (BU/BN), harness side and DCSM C3265A-D, circuit RHS06 (WH), harness side.
- Is the resistance between 0.9 and 10 ohms?
Yes
GO to AG10.
No
GO to AG9.
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AG9 CHECK THE PASSENGER BACKREST TED RESISTANCE
- Disconnect: Passenger Backrest TED C3039.
- Measure the resistance between passenger backrest TED C3039 pins 1 and 3, component side.
- Is the resistance between 0.9 and 10 ohms?
Yes
REPAIR circuit(s) CHS06 (BU/BN) and/or RHS06 (WH) for an open. CLEAR the DTCs. REPEAT the self-test.
For vehicles equipped with seat side air bags, DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C339. REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
No
INSTALL a new passenger backrest TED. REFER to Seat Backrest - Front, Bucket Seat Bucket Seat. CLEAR the DTCs. REPEAT the self-test.
For vehicles equipped with seat side air bags, DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C339. REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
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AG10 CHECK THE BLOWER AND SPEED CONTROL CIRCUITS FOR A SHORT TO VOLTAGE
- Disconnect: DCSM C3265C.
- Ignition ON.
- Measure the voltage between:
- DCSM C3265C-8, circuit CHS08 (BN/YE), harness side and ground.
- DCSM C3265C-3, circuit VHS23 (BN/BU), harness side and ground.
- Is any voltage present on either circuit?
Yes
REPAIR the circuit(s). CLEAR the DTCs. REPEAT the self-test.
For vehicles equipped with seat side air bags, DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C339. REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
No
GO to AG11.
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AG11 CHECK THE BLOWER AND SPEED CONTROL CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between:
- DCSM C3265C-8, circuit CHS08 (BN/YE), harness side and ground.
- DCSM C3265C-3, circuit VHS23 (BN/BU), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
GO to AG12.
No
REPAIR the circuit(s). CLEAR the DTCs. REPEAT the self-test.
For vehicles equipped with seat side air bags, DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C339. REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
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AG12 CHECK THE BLOWER AND WIRING RESISTANCE
- NOTE: The ohmmeter must be connected with the positive lead to DCSM C3265C-8, circuit CHS08 (BN/YE) and the negative lead to DCSM C3265C-7, circuit RHS08 (VT/WH) when measuring. Ohmmeter leads incorrectly connected can result in false readings and lead to incorrect identification of components that are not faulty.
- Measure the resistance between DCSM C3265C-8, circuit CHS08 (BN/YE), harness side and DCSM C3265C-7, circuit RHS08 (VT/WH), harness side.
- Is the resistance between 4,000 and 10,000 ohms?
Yes
GO to AG14.
No
GO to AG13.
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AG13 CHECK THE BLOWER RESISTANCE
- Disconnect: Passenger Cushion TED C3040.
- 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 can result in false readings and lead to incorrect identification of components that are not faulty.
- Measure the resistance between passenger cushion TED C3040 pins 2 and 4, component side.
- Is the resistance between 4,000 and 10,000 ohms?
Yes
REPAIR circuit(s) CHS08 (BN/YE) and/or RHS08 (VT/WH) for an open. CLEAR the DTCs. REPEAT the self-test.
For vehicles equipped with seat side air bags, DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C339. REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
No
INSTALL a new passenger cushion TED. REFER to Seat Cushion - Front, Bucket Seat Bucket Seat. CLEAR the DTCs. REPEAT the self-test.
For vehicles equipped with seat side air bags, DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C339. REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
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AG14 CHECK THE BLOWER SPEED CONTROL AND CIRCUIT RESISTANCE
- NOTE: The ohmmeter must be connected with the positive lead to C3265C-3, circuit VHS23 (BN/BU), harness side and the negative lead to C3265C-7, circuit RHS08 (VT/WH), harness side when measuring. Ohmmeter leads incorrectly connected can result in false readings and lead to incorrect identification of components that are not faulty.
- Measure the resistance between DCSM C3265C-3, circuit VHS23 (BN/BU), harness side and DCSM C3265C-7, circuit RHS08 (VT/WH), harness side.
- Is the resistance between 240K ohms and 4M ohms?
Yes
GO to AG16.
No
GO to AG15.
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AG15 CHECK THE BLOWER SPEED CONTROL RESISTANCE
- Disconnect: Passenger Cushion TED C3040.
- 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 can result in false readings and lead to incorrect identification of components that are not faulty.
- Measure the resistance between passenger cushion TED C3040 pins 7 and 4, component side.
- Is the resistance between 240K ohms and 4M ohms?
Yes
REPAIR circuit(s) VHS23 (BN/BU) and/or RHS08 (VT/WH) for an open. CLEAR the DTCs. REPEAT the self-test.
For vehicles equipped with seat side air bags, DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C339. REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
No
INSTALL a new passenger cushion TED. REFER to Seat Cushion - Front, Bucket Seat Bucket Seat. CLEAR the DTCs. REPEAT the self-test.
For vehicles equipped with seat side air bags, DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C339. REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
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AG16 CHECK THE THERMISTOR CIRCUIT FOR A SHORT TO VOLTAGE
NOTE: If a seat equipped with a seat mounted side air bag is being serviced, the Supplemental Restraint System (SRS) must be depowered. Refer to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
NOTE: The air bag warning lamp illuminates when the Restraints Control Module (RCM) fuse is removed and the ignition switch is ON. This is normal operation and does not indicate an SRS fault.
NOTE: The SRS must be fully operational and free of faults before releasing the vehicle to the customer.
- Ignition OFF.
- 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.
- For vehicles equipped with seat side air bags, carry out the following:
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
- Disconnect the passenger seat side air bag module C339.
- Connect the battery ground cable. Refer to Battery, Mounting and Cables Battery Disconnect / Connect.
- Disconnect: DCSM C3265B.
- Ignition ON.
- Measure the voltage between DCSM C3265B-2, circuit VHS27 (WH/OG), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
For vehicles equipped with seat side air bags, DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C339. REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
No
GO to AG17.
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AG17 CHECK THE THERMISTOR CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between DCSM C3265B-2, circuit VHS27 (WH/OG), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to AG18.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
For vehicles equipped with seat side air bags, DISCONNECT the battery ground cable. CONNECT passenger seat side air bag module C339. REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
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AG18 CHECK THE TED THERMISTOR AND WIRING RESISTANCE
- Measure the resistance between DCSM C3265B-2, circuit VHS27 (WH/OG), harness side and DCSM C3265B-3, circuit RHS10 (BU/OG), harness side. Note the ambient temperature and compare result to the following table:
- Is the resistance within the limits indicated?
Yes
GO to AG35.
No
GO to AG19.
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