Pinpoint Test AP: DTC B2729
Seats
Pinpoint Tests
Pinpoint Test AP: DTC B2729
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) monitors the temperature sensor. If the temperature exceeds the specified limits, the DTC will be set.
The presence of overtemperature faults (DTCs B2729, B2730, B272A and B272B) can be induced by incorrect operation of the climate controlled seat system after an initial heat setting has been attained. If a heat setting is repeatedly turned OFF and ON in an attempt to increase the seat temperature or repeatedly toggled between heat and cool modes, an overtemperature condition can result and the DTCs will be set.
- DTC B2729 (Cushion Over-Temp Detected) - For heat mode, if the driver seat cushion TED temperature exceeds 110°C (230°F) continuously for more than 4 seconds in any heat mode, the DCSM turns off the TED and enters a fan only state to recover from the over-temperature condition (recovery mode). If the TED temperature does not recover after 30 seconds, the DTC will set and the seat is disabled. If the TED does recover, the TED is re-enabled, the system continues to operate normally and the DTC will not be set. If the over-temperature condition occurs a second time within the same ignition cycle, the DTC will set and the seat is disabled.
- DTC B2729 (Cushion Over-Temp Detected) - For cool mode, if the driver seat cushion TED temperature exceeds 65°C (149°F) continuously for more than 4 seconds in any cool mode, the DCSM turns off the TED and enters a fan only state to recover from the over-temperature condition (recovery mode). If the TED temperature does not recover after 5 minutes, the DTC will set and the seat is disabled. If the TED does recover, the TED is re-enabled, the system continues to operate normally and the DTC will not be set. If the over-temperature condition occurs a second time within the same ignition cycle, the DTC will set and the seat is disabled.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Restricted cushion TED filter
- Crushed or restricted foam pad
- Cushion TED assembly
PINPOINT TEST AP: DTC B2729
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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AP1 CHECK THE CUSHION BLOWER FOR AN OBSTRUCTION OR RESTRICTED FILTER
- Check the seat for any obstruction at the TED assembly and for a restricted filter.
- Is the filter clean and blower clear of any obstruction?
Yes
GO to AP2.
No
REMOVE the obstruction or INSTALL a new filter. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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AP2 CHECK THE OPERATION OF THE SEAT AND MONITOR SEAT TEMPERATURE USING THE SCAN TOOL
- Enter the following diagnostic mode on the scan tool: DataLogger - DCSM - PIDs:.
- Seat cushion thermal electric device temperature (CSHTEMP)
- Seat back thermal electric device temperature (BK_TEMP)
- Start the engine.
- Operate the seat in high heat or high cool and monitor the seat operation. If a circuit fault is present, the DCSM will disable the seat.
- Monitor the cushion and backrest temperature PIDs while the seat is operating. The temperatures should be similar during operation.
- Does the seat operate and temperature PIDs indicate correct operation?
Yes
The system is operating correctly at this time. The fault may have occurred from incorrectly switching between heat and cool modes. CLEAR the DTCs. REPEAT the self-test.
No
If the seat is operational, but the cushion temperature increases greater than the backrest, GO to AP3.
If the seat does not operate, GO to AP4.
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AP3 CHECK THE TED FOR CORRECT INSTALLATION AND FOR A CRUSHED FOAM PAD
- Remove the seat cushion cover. Refer to Seat Cushion Cover - Front Seat Cushion Cover - Front.
- Check the TED and climate controlled seat manifold (part of foam pad) for damage, restriction and for correct installation.
- Is the TED correctly installed and foam pad OK?
Yes
INSTALL a new cushion TED. REFER to Seat Cushion Thermo-Electric Device - Front Row Seat Cushion Thermo-Electric Device - Front Row. CLEAR the DTCs.
REPEAT the self-test. TEST the system for normal operation.
No
CORRECTLY install the cushion TED or INSTALL a new foam pad. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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AP4 CHECK THE TED THERMISTOR CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of Restraint Systems.
- Disconnect: Driver Seat Side Air Bag Module C3378.
- Disconnect: Driver Seat Safety Belt Buckle Pretensioner C3065.
- Disconnect: Passenger Seat Side Air Bag Module C3377.
- Disconnect: Passenger Seat Safety Belt Buckle Pretensioner C3066.
- Disconnect: DCSM C3265B.
- Disconnect: Cushion TED C3035.
- 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 AP5.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable.
CONNECT passenger seat safety belt buckle pretensioner C3066.
CONNECT passenger seat side air bag module C3377.
CONNECT driver seat safety belt buckle pretensioner C3065.
CONNECT driver seat side air bag module C3378.
REPOWER the SRS. REFER to Restraint Systems.
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AP5 CHECK THE TED THERMISTOR CIRCUITS FOR A SHORT TOGETHER
- Measure the resistance between DCSM C3265B-7, circuit VHS26 (VT), harness side and DCSM C3265B-8, circuit RHS05 (YE/VT), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
GO to AP6.
No
REPAIR the circuit(s). CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable.
CONNECT passenger seat safety belt buckle pretensioner C3066.
CONNECT passenger seat side air bag module C3377.
CONNECT driver seat safety belt buckle pretensioner C3065.
CONNECT driver seat side air bag module C3378.
REPOWER the SRS. REFER to Restraint Systems.
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AP6 CHECK THE BLOWER CIRCUITS FOR AN OPEN
- Measure the resistance between:
- DCSM C3265C-16, circuit CHS03 (GN/BN), harness side and cushion TED C3035-2, circuit CHS03 (GN/BN), harness side.
- DCSM C3265C-15, circuit RHS03 (GY/OG), harness side and cushion TED C3035-4, circuit RHS03 (GY/OG), harness side.
- DCSM C3265C-11, circuit VHS18 (BN/GN), harness side and cushion TED C3035-7, circuit VHS18 (BN/GN), harness side.
- Are the resistances less than 5 ohms?
Yes
INSTALL a new cushion TED. REFER to Seat Cushion Thermo-Electric Device - Front Row Seat Cushion Thermo-Electric Device - Front Row. CLEAR the DTCs.
REPEAT the self-test.
DISCONNECT the battery ground cable.
CONNECT passenger seat safety belt buckle pretensioner C3066.
CONNECT passenger seat side air bag module C3377.
CONNECT driver seat safety belt buckle pretensioner C3065.
CONNECT driver seat side air bag module C3378.
REPOWER the SRS. REFER to Restraint Systems.
No
REPAIR the circuit(s). TEST the system for normal operation. CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable.
CONNECT passenger seat safety belt buckle pretensioner C3066.
CONNECT passenger seat side air bag module C3377.
CONNECT driver seat safety belt buckle pretensioner C3065.
CONNECT driver seat side air bag module C3378.
REPOWER the SRS. REFER to Restraint Systems.
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