AP1-AP20
Seats
Pinpoint Tests
Pinpoint Test AP: DTC B272C
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. Both voltage supply circuits to the DCSM are spliced together internally, 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 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 B272C (Driver Differential Temperature Fault) - If there is a temperature differential between the driver backrest and cushion TED of 60°C (108°F) or more for more than 4 seconds, if the TED is disconnected or if the duct is blocked, this DTC sets. When this happens the first time in a key cycle, the DCSM puts the driver 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 driver 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 AP: DTC B272C
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: If a seat equipped with a seat mounted side air bag is being repaired, 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.
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AP1 CHECK FOR DCSM DTCs
- Enter the following diagnostic mode on the scan tool: Self Test - DCSM.
- Was DTC B2729 or B2730 retrieved?
Yes
For DTC B2729, GO to Pinpoint Test AM. For DTC B2730, GO to Pinpoint Test AT. Pinpoint Test AM: DTC B2729 Pinpoint Test AT: DTC B2730
No
GO to AP2.
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AP2 MONITOR THE DCSM TED TEMPERATURE PIDs
- Enter the following diagnostic mode on the scan tool: DataLogger - DCSM.
- Passenger Cushion TED Temperature (PCSHTMP)
- Passenger Back TED Temperature (PBKTMP)
- Seat cushion TED temperature (CSHTEMP)
- Seat 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 TED temperature PIDs with the climate controlled seats OFF. Compare the PID values of the driver seat to those of the front passenger seat, this can help identify if there is a concern with the driver seat cushion or backrest PID value readings.
- Are both driver seat TED temperature PIDs within 10°C (18°F) of the ambient temperature?
Yes
GO to AP3.
No
If the driver seat cushion PID varies 10°C (18°F) or more from ambient temperature, GO to AP16.
If the driver seat backrest PID varies 10°C (18°F) or more from ambient temperature, GO to AP31.
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AP3 CONFIRM THE FAULT IS IN THE SEAT CUSHION OR THE 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 driver 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 driver seat.
- Do the driver seat cushion TED and backrest TED PIDs vary more than 60°C (108°F) from each other?
Yes
If the driver seat cushion PID is 60°C (108°F) hotter than the backrest PID, GO to AP5.
If the driver seat backrest PID is 60°C (108°F) hotter than the cushion PID, GO to AP20.
No
GO to AP4.
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AP4 CHECK THE TEDs COOLING PERFORMANCE
- Check the 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. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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AP5 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 AP6.
No
CORRECTLY install the cushion TED or INSTALL a new seat cushion foam pad and/or climate controlled seat manifold. INSTALL the seat. CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
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AP6 CHECK THE BACKREST TED- CIRCUIT FOR A SHORT TO VOLTAGE
NOTE: If a seat equipped with a seat mounted side air bag is being repaired, 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.
- Position the driver seat in the vehicle and connect the seat-to-floor connectors.
- Disconnect: Driver Seat Side Air Bag Module C3051.
- Disconnect: Passenger Seat Side Air Bag Module C339.
- 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. Refer to Battery, Mounting and Cables Battery Disconnect.
- Ignition ON.
- Measure the voltage between DCSM C3265A-K, circuit RHS01 (WH/VT), 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 driver seat side air bag module C3051 and 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 AP7.
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AP7 CHECK THE BACKREST TED+ CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between DCSM C3265A-J, circuit CHS01 (GY/VT), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to AP8.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C3051 and 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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AP8 CHECK THE BACKREST TED AND WIRING RESISTANCE
- Measure the resistance between DCSM C3265A-J, circuit CHS01 (GY/VT), harness side and DCSM C3265A-K, circuit RHS01 (WH/VT), harness side.
- Is the resistance between 0.9 and 10 ohms?
Yes
GO to AP10.
No
GO to AP9.
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AP9 CHECK THE BACKREST TED RESISTANCE
- Disconnect: Backrest TED C3034.
- Measure the resistance between backrest TED C3034 pins 1 and 3, component side.
- Is the resistance between 0.9 and 10 ohms?
Yes
REPAIR the circuit(s). CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C3051 and 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 backrest TED. REFER to Seat Backrest Thermo-Electric Device Seat Backrest Thermo-Electric Device. CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C3051 and 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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AP10 CHECK THE BLOWER AND SPEED CONTROL CIRCUITS FOR A SHORT TO VOLTAGE
- Disconnect: DCSM C3265C.
- Ignition ON.
- Measure the voltage between:
- DCSM C3265C-16, circuit CHS03 (GN/BN), harness side and ground.
- DCSM C3265C-11, circuit VHS18 (BN/GN), harness side and ground.
- Is any voltage present on either circuit?
Yes
REPAIR the circuit(s). CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C3051 and 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 AP11.
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AP11 CHECK THE BLOWER AND SPEED CONTROL CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between:
- DCSM C3265C-16, circuit CHS03 (GN/BN), harness side and ground.
- DCSM C3265C-11, circuit VHS18 (BN/GN), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
GO to AP12.
No
REPAIR the circuit(s). CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C3051 and 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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AP12 CHECK THE BLOWER AND WIRING RESISTANCE
- NOTE: The ohmmeter must be connected with the positive lead to DCSM C3265C-16, circuit CHS03 (GN/BN) and the negative lead to DCSM C3265C-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 C3265C-16, circuit CHS03 (GN/BN), harness side and DCSM C3265C-15, circuit RHS03 (GY/OG), harness side.
- Is the resistance between 4,000 and 10,000 ohms?
Yes
GO to AP14.
No
GO to AP13.
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AP13 CHECK THE BLOWER RESISTANCE
- Disconnect: Cushion TED C3035.
- 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 C3035 pins 2 and 4, component side.
- Is the resistance between 4,000 and 10,000 ohms?
Yes
REPAIR the circuit(s). CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C3051 and 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 cushion TED. REFER to Seat Cushion Thermo-Electric Device Seat Cushion Thermo-Electric Device. CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C3051 and 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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AP14 CHECK THE BLOWER SPEED CONTROL AND CIRCUIT RESISTANCE
- NOTE: The ohmmeter must be connected with the positive lead to C3265C-11, circuit VHS18 (BN/GN), harness side and the negative lead to C3265C-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 C3265C-11, circuit VHS18 (BN/GN) harness side and DCSM C3265C-15, circuit RHS03 (GY/OG), harness side.
- Is the resistance between 240K ohms and 4M ohms?
Yes
GO to AP16.
No
GO to AP15.
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AP15 CHECK THE BLOWER SPEED CONTROL RESISTANCE
- Disconnect: Cushion TED C3035.
- 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 C3035 pins 7 and 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 driver seat side air bag module C3051 and 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 cushion TED. REFER to Seat Cushion Thermo-Electric Device Seat Cushion Thermo-Electric Device. CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C3051 and 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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AP16 CHECK THE THERMISTOR CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
- Disconnect: Driver Seat Side Air Bag Module C3051.
- Disconnect: Passenger Seat Side Air Bag Module C339.
- 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. Refer to Battery, Mounting and Cables Battery Disconnect.
- Ignition ON.
- Measure the voltage between DCSM C3265B-7, circuit VHS26 (VT), 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 driver seat side air bag module C3051 and 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 AP17.
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AP17 CHECK THE THERMISTOR CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between DCSM C3265B-7, circuit VHS26 (VT), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to AP18.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C3051 and 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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AP18 CHECK THE TED THERMISTOR AND WIRING RESISTANCE AT THE DCSM
- Measure the resistance between DCSM C3265B-7, circuit VHS26 (VT), harness side and DCSM C3265B-8, circuit RHS05 (YE/VT), harness side. Note the ambient temperature and compare result to the following table:
- Is the resistance within the limits indicated?
Yes
INSTALL a new DCSM. REFER to Dual Climate Controlled Seat Module (DCSM) Dual Climate Controlled Seat Module (DCSM). CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C3051 and 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 AP19.
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AP19 CHECK THE TED THERMISTOR RESISTANCE
- Disconnect: Cushion TED C3035.
- Measure the resistance between cushion TED pins 5 and 8, component side. Note the ambient temperature and compare result to the following table:
- Is the resistance within the limits indicated?
Yes
REPAIR the circuit(s) for high resistance. CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C3051 and 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 cushion TED. REFER to Seat Cushion Thermo-Electric Device Seat Cushion Thermo-Electric Device. CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C3051 and 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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AP20 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 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 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 AP21.
No
CORRECTLY install the backrest TED or INSTALL a new seat backrest foam pad and/or climate controlled seat manifold. INSTALL the seat. CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
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