Pinpoint Tests BL: DTC B2729
Seats
Pinpoint Test BL: DTC B2729
Refer to Wiring Diagram Set 119, Climate Controlled Seats for schematic and connector information. Diagrams By Number
Normal Operation
The Passenger Climate Controlled Seat Module - 2 (PCSM-2) 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 BL: DTC B2729
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BL1 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 BL2.
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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BL2 CHECK THE OPERATION OF THE SEAT AND MONITOR SEAT TEMPERATURE USING THE SCAN TOOL
- Enter the following diagnostic mode on the scan tool: DataLogger - PCSM-2 - 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 PCSM-2 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 BL3.
If the seat does not operate, GO to BL4.
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BL3 CHECK THE TED FOR CORRECT INSTALLATION AND FOR A CRUSHED FOAM PAD
- Remove the seat cushion cover. Refer to Seat Cushion Cover - Second Row, Bucket Seat Cushion Cover - Second Row, Bucket.
- 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?
Yes
INSTALL a new cushion TED. REFER to Seat Cushion Thermo-Electric Device - Second Row Seat Cushion Thermo-Electric Device - Second 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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BL4 CHECK THE TED THERMISTOR CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: PCSM-2 C3365B.
- Disconnect: Cushion TED C3358.
- Measure the resistance between PCSM-2 C3365B-7, circuit VHS42 (GN), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to BL5.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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BL5 CHECK THE TED THERMISTOR CIRCUITS FOR A SHORT TOGETHER
- Measure the resistance between PCSM-2 C3365B-7, circuit VHS42 (GN), harness side and PCSM-2 C3365B-8, circuit RHS42 (BN/WH), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
GO to BL6.
No
REPAIR the circuit(s). CLEAR the DTCs. REPEAT the self-test.
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BL6 CHECK THE BLOWER CIRCUITS FOR AN OPEN
- Measure the resistance between:
- PCSM-2 C3365C-16, circuit CHS67 (VT/BN), harness side and cushion TED C3358-2, circuit CHS67 (VT/BN), harness side.
- PCSM-2 C3365C-15, circuit RHS67 (WH/BU), harness side and cushion TED C3358-4, circuit RHS67 (WH/BU), harness side.
- Are the resistances less than 5 ohms?
Yes
INSTALL a new cushion TED. REFER to Seat Cushion Thermo-Electric Device - Second Row Seat Cushion Thermo-Electric Device - Second Row. CLEAR the DTCs. REPEAT the self-test.
No
REPAIR the circuit(s). TEST the system for normal operation. CLEAR the DTCs. REPEAT the self-test.
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