Pinpoint Test AT1-AT17
Seats
Pinpoint Tests
Pinpoint Test AT: DTC B272C
Refer to Wiring Diagram Set 119, Climate Controlled Seats for schematic and connector information. Diagrams By Number
Normal Operation
Both the driver and front passenger climate controlled seats are independently controlled electronically 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 engine OFF. The system receives voltage from Battery Junction Box (BJB) fuse 67 (40A) feeding battery voltage on circuit SBB08 (VT/RD) into DCSM C3265A pins E and F. If voltage is disconnected from either pin E or F of DCSM C3265A with the voltage connection remaining on the other circuit, both seats will remain operational because the voltage feed 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 module and the other will remain operational.
Each driver and front passenger 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, each driver and front passenger 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 climate controlled seat switch settings.
A differential fault occurs when the cushion and backrest TEDs on the seat are reporting temperatures to the DCSM with a difference between them of 60°C (108°F) or greater. This can result from an airflow restriction or a circuit fault at either TED. 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, 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 driver seat system into recovery mode, refer to 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 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 AT: 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: 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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AT1 CHECK THE DCSM FOR ON-DEMAND DTCs
- Enter the following diagnostic mode on the scan tool: Self Test - DCSM.
- Was DTC B2729 or B2730 retrieved on-demand during the self-test?
Yes
For DTC B2729, GO to Pinpoint Test AQ. For DTC B2730, GO to Pinpoint Test AX. Pinpoint Test AQ: DTC B2729 Pinpoint Test AX: DTC B2730
No
GO to AT2.
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AT2 MONITOR THE DCSM TED TEMPERATURE PIDs
- Enter the following diagnostic mode on the scan tool: DataLogger - DCSM - PIDs.
- Passenger Cushion TED Temperature (PCSHTMP)
- Passenger Back TED Temperature (PBKTMP)
- Seat cushion thermal electric device temperature (CSHTEMP)
- Seat back thermal electric device temperature (BK_TEMP)
- NOTICE: 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 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 PID values within 10°C (18°F) of the ambient temperature?
Yes
GO to AT3.
No
If the driver seat cushion PID value varies 10°C (18°F) or more from ambient temperature, GO to AT16.
If the driver seat backrest PID value varies 10°C (18°F) or more from ambient temperature, GO to AT31.
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AT3 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. 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 or backrest PID values vary more than 60°C (108°F)?
Yes
If the driver seat cushion PID value is 60°C (108°F) hotter than the backrest PID value, GO to AT5.
If the driver seat backrest PID value is 60°C (108°F) hotter than the cushion PID value, GO to AT20.
No
GO to AT4.
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AT4 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.
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AT5 CHECK THE TED INSTALLATION AND FOR A CRUSHED SEAT CUSHION
- Ignition OFF.
- 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.
- Remove the seat. Refer to Seat - Front Seat - Front.
- Remove the seat cushion 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 are there no signs of damage to the foam pad and manifold?
Yes
GO to AT6.
No
CORRECTLY install the cushion TED or INSTALL a new seat cushion foam pad and/or climate controlled seat manifold. CONNECT the battery ground cable. REFER to Battery, Mounting and Cables Battery Disconnect. CLEAR the DTCs. REPEAT the self-test.
REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
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AT6 CHECK THE BACKREST TED CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: DCSM C3265A.
- NOTE: Do not connect the safety belt buckle pretensioner or seat side air bag electrical connectors at this time.
- Position the driver seat in the vehicle and connect the seat-to-floor connectors.
- 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 the voltage less than 0.5 volt?
Yes
GO to AT7.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.
CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.
REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
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AT7 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 AT8.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.
CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.
REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
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AT8 CHECK RESISTANCE OF THE BACKREST TED AND WIRING
- 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 AT10.
No
GO to AT9.
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AT9 CHECK RESISTANCE OF THE BACKREST TED
- Disconnect: Backrest TED C3034.
- Measure the resistance between backrest TED C3034 pin 1 and pin 3, component side.
- Is the resistance between 0.9 and 10 ohms?
Yes
REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.
CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.
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 safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.
CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.
REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
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AT10 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 CHS13 (VT/BN), harness side and ground.
- DCSM C3265C-11, circuit CHS03 (GN/BN), harness side and ground.
- Is voltage present on any circuit?
Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.
CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.
REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
No
GO to AT11.
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AT11 CHECK THE BLOWER AND SPEED CONTROL CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between:
- DCSM C3265C-16, circuit CHS13 (VT/BN), harness side and ground.
- DCSM C3265C-11, circuit CHS03 (GN/BN), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
GO to AT12.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.
CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.
REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
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AT12 CHECK THE BLOWER AND WIRING
- NOTICE: The ohmmeter must be connected with the positive lead to Dual Climate Controlled Seat Module (DCSM) C3265C-16, circuit CHS13 (VT/BN) and the negative lead to DCSM C3265C-15, circuit CHS03 (GN/BN) 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 CHS13 (VT/BN), harness side and DCSM C3265C-15, circuit CHS03 (GN/BN), harness side.
- Is the resistance between 4,000 ohms and 10,000 ohms?
Yes
GO to AT14.
No
GO to AT13.
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AT13 CHECK THE BLOWER
- Disconnect: Cushion TED C3035.
- NOTICE: 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 pin 2 and pin 4, component side.
- Is the resistance between 4,000 ohms and 10,000 ohms?
Yes
REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.
CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.
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 safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.
CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.
REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
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AT14 CHECK THE BLOWER SPEED CONTROL AND CIRCUIT
- NOTICE: The ohmmeter must be connected with the positive lead to C3265C-11, circuit CHS03 (GN/BN), harness side and the negative lead to C3265C-15, circuit CHS03 (GN/BN), 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 CHS03 (GN/BN) harness side and DCSM C3265C-15, circuit CHS03 (GN/BN), harness side.
- Is the resistance between 240K ohms and 4M ohms?
Yes
GO to AT16.
No
GO to AT15.
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AT15 CHECK THE BLOWER SPEED CONTROL
- Disconnect: Cushion TED C3035.
- NOTICE: 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 pin 7 and pin 4, component side.
- Is the resistance between 240K ohms and 4M ohms?
Yes
REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.
CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.
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 safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.
CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.
REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
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AT16 CHECK THE 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 Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
- Disconnect: Driver Seat Safety Belt Buckle Pretensioner C3049 and Passenger Seat Safety Belt Buckle Pretensioner C3050.
- Disconnect: Driver Seat Side Air Bag C3051 and Passenger Seat Side Air Bag C3052.
- 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 the voltage less than 0.5 volt?
Yes
GO to AT17.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.
CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.
REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
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AT17 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 AT18.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT driver seat safety belt buckle pretensioner C3049 and passenger seat safety belt buckle pretensioner C3050.
CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C3052.
REPOWER the SRS. REFER to Supplemental Restraint System Supplemental Restraint System (SRS) Depowering and Repowering.
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