AM1-AM17
Seats
Pinpoint Tests
Pinpoint Test AM: 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 ON. The system receives voltage from Battery Junction Box (BJB) fuse 22 (30A) supplying voltage into DCSM C3265a pins E and F, circuit CBX01 (GN/RD). If voltage is disconnected from either pin E or F of DCSM C3265a 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 DCSM.
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). Cabin air is drawn through the blower and distributed to each of the TED modules. 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 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 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.
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AM1 CHECK 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 AJ. For DTC B272B, Go To Pinpoint Test AK. Pinpoint Test AJ: DTC B272A Pinpoint Test AK: DTC B272B
No
GO to AM2.
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AM2 MONITOR DCSM TED TEMPERATURE PIDs
- Enter the following diagnostic mode on the scan tool: DataLogger - DCSM - PIDs.
- Passenger cushion thermal electric device (TED) temperature (PCSHTMP)
- Passenger back TED temperature (PBKTMP)
- Seat cushion thermal electric device temperature (CSHTEMP)
- Seat back thermal electric device 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 AM3.
No
If the front passenger seat cushion PID varies 10°C (18°F) or more from ambient temperature, GO to AM16.
If the front passenger seat backrest PID varies 10°C (18°F) or more from ambient temperature, GO to AM32.
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AM3 CONFIRM 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). 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 AM5.
If the front passenger seat backrest PID is 60°C (108°F) hotter than the cushion PID, GO to AM20.
No
GO to AM4.
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AM4 CHECK 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. REPEAT the self-test. 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. REPEAT the self-test. CLEAR the DTCs.
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AM5 CHECK FOR CORRECT TED INSTALLATION AND FOR CRUSHED FOAM
- Ignition OFF.
- Remove the seat. Refer to Seat - Front Seat - Front.
- Remove the seat cushion trim cover. Refer to Seat Cushion Cover - Front Seat Cushion Cover - Front.
- 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 AM6.
No
CORRECTLY install the cushion TED or INSTALL a new seat cushion foam pad and/or climate controlled seat manifold. REPEAT the self-test. CLEAR the DTCs.
INSTALL the seat. REFER to Seat - Front Seat - Front.
REPEAT the self-test. CLEAR the DTCs.
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AM6 CHECK 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.
- 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 C3133.
- Disconnect: Passenger Safety Belt Buckle Pretensioner C3066.
- Disconnect: DCSM 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 C3265a-D, circuit RHS06 (WH), 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 safety belt buckle pretensioner C3066.
CONNECT passenger seat side air bag module C3133.
REPOWER the SRS. REFER to Air Bag Systems.
No
GO to AM7.
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AM7 CHECK 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 AM8.
No
REPAIR the circuit. REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable.
CONNECT passenger safety belt buckle pretensioner C3066.
CONNECT passenger seat side air bag module C3133.
REPOWER the SRS. REFER to Air Bag Systems.
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AM8 CHECK THE RESISTANCE OF THE BACKREST TED AND WIRING
- 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 AM10.
No
GO to AM9.
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AM9 CHECK THE RESISTANCE OF THE BACKREST TED
- Disconnect: Backrest TED C3039.
- Measure the resistance between backrest TED C3039 pin 1 and pin 3, component side.
- Is the 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 safety belt buckle pretensioner C3066.
CONNECT passenger seat side air bag module C3133.
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 safety belt buckle pretensioner C3066.
CONNECT passenger seat side air bag module C3133.
REPOWER the SRS. REFER to Air Bag Systems.
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AM10 CHECK BLOWER CIRCUIT AND SPEED CONTROL CIRCUIT 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 voltage present on either circuit?
Yes
REPAIR the circuit(s). REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable.
CONNECT passenger safety belt buckle pretensioner C3066.
CONNECT passenger seat side air bag module C3133.
REPOWER the SRS. REFER to Air Bag Systems.
No
GO to AM11.
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AM11 CHECK 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 AM12.
No
REPAIR the circuit(s). REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable.
CONNECT passenger safety belt buckle pretensioner C3066.
CONNECT passenger seat side air bag module C3133.
REPOWER the SRS. REFER to Air Bag Systems.
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AM12 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 will 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 ohms and 10,000 ohms?
Yes
GO to AM14.
No
GO to AM13.
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AM13 CHECK THE BLOWER RESISTANCE
- Disconnect: 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 will result in false readings and lead to incorrect identification of components that are not faulty.
- Measure the resistance between cushion TED C3040 pin 2 and pin 4, component side.
- Is the resistance between 4,000 ohms and 10,000 ohms?
Yes
REPAIR the circuit(s). REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable.
CONNECT passenger safety belt buckle pretensioner C3066.
CONNECT passenger seat side air bag module C3133.
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 safety belt buckle pretensioner C3066.
CONNECT passenger seat side air bag module C3133.
REPOWER the SRS. REFER to Air Bag Systems.
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AM14 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 will 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 AM16.
No
GO to AM15.
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AM15 CHECK THE BLOWER SPEED CONTROL RESISTANCE
- Disconnect: 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 will result in false readings and lead to incorrect identification of components that are not faulty.
- Measure the resistance between cushion TED C3040 pin 7 and pin 4, component side.
- Is the resistance between 240K ohms and 4M ohms?
Yes
REPAIR the circuit(s). REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable.
CONNECT passenger safety belt buckle pretensioner C3066.
CONNECT passenger seat side air bag module C3133.
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 safety belt buckle pretensioner C3066.
CONNECT passenger seat side air bag module C3133.
REPOWER the SRS. REFER to Air Bag Systems.
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AM16 CHECK THERMISTOR CIRCUIT 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 Air Bag Systems.
- Disconnect: Passenger Seat Side Air Bag C3133.
- Disconnect: Passenger Safety Belt Buckle Pretensioner C3066.
- Disconnect: DCSM C3265b.
- 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 C3265b-2, circuit VHS27 (WH/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 passenger safety belt buckle pretensioner C3066.
CONNECT passenger seat side air bag module C3133.
REPOWER the SRS. REFER to Air Bag Systems.
No
GO to AM17.
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AM17 CHECK 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 volts?
Yes
GO to AM18.
No
REPAIR the circuit. REPEAT the self-test. CLEAR the DTCs.
DISCONNECT the battery ground cable.
CONNECT passenger safety belt buckle pretensioner C3066.
CONNECT passenger seat side air bag module C3133.
REPOWER the SRS. REFER to Air Bag Systems.
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