Pinpoint Test AM: DTC B2729

Seats

Pinpoint Test AM: DTC B2729

Normal Operation

The Dual Climate Controlled Seat Module (DCSM) monitors seat cushion temperature while it supplies voltage and ground to both blower motors. The DCSM (Dual Climate Controlled Seat Module) also supplies a variable voltage signal to control the blower speed. Cabin air enters the blower through a filter attached to the Thermo-Electric Device (TED) housing. Heated or cooled air exits the TED (Thermo-Electric Device) and flows through a manifold attached to the foam pad.

- DTC B2729 (Cushion Over-Temp Detected)- If the driver seat cushion TED (Thermo-Electric Device) temperature exceeds 85°C (185°F) in heat mode or 70°C (158°F) in cool mode for more than 34 seconds the DCSM (Dual Climate Controlled Seat Module) shuts down the driver seat system and sets this DTC.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- Restricted cushion TED (Thermo-Electric Device) filter

- Crushed or restricted climate controlled seat manifold

- Cushion TED (Thermo-Electric Device) assembly

PINPOINT TEST AM : DTC B2729

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.

AM1 CHECK THE DCSM (Dual Climate Controlled Seat Module) FOR ON-DEMAND DTCs

- Start the vehicle and set the driver seat to HIGH heat.

- Enter the following diagnostic mode on the scan tool: Self Test- DCSM (Dual Climate Controlled Seat Module).

Was DTC B2729 retrieved on-demand during the self-test?

Yes
GO to AM2.
No
GO to AM5.

AM2 CHECK THE DRIVER SEAT CUSHION TED (Thermo-Electric Device) THERMISTOR CIRCUITS FOR A SHORT TO GROUND

- Ignition OFF.

- Depower the SRS (Supplemental Restraint System). Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of Restraints and Safety Systems &/or Air Bag Systems.

- Disconnect: Driver Seat Side Air Bag C3051 and Passenger Seat Side Air Bag C339.

- Disconnect: DCSM (Dual Climate Controlled Seat Module) C3265B.

- Disconnect: Driver Seat Cushion TED (Thermo-Electric Device) C3035.

- 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.

- Measure the resistance between:
- DCSM (Dual Climate Controlled Seat Module) C3265B-7, circuit VHS26 (VT), harness side and ground.

- DCSM (Dual Climate Controlled Seat Module) C3265B-8, circuit RHS05 (YE/VT), harness side and ground.

Are the resistances greater than 10,000 ohms?

Yes
GO to AM3.
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 (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AM3 CHECK THE DRIVER SEAT CUSHION TED (Thermo-Electric Device) THERMISTOR AND WIRING

- Connect: Driver Seat Cushion TED (Thermo-Electric Device) C3035.

- Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3265B-7, circuit VHS26 (VT), harness side and DCSM (Dual Climate Controlled Seat Module) C3265B-8, circuit RHS05 (YE/VT), harness side. Note the ambient temperature and refer to the following table.

Temperature Resistance 0-10°C (32-50°F) 2,782-1,663 ohms 10-20°C (50-68°F) 1,837-1,140 ohms 20-30°C (68-86°F) 1,260-806 ohms 30-40°C (86-104°F) 893-570 ohms 40-50°C (104-122°F) 630-428 ohms

Is the resistance within the limits indicated?

Yes
GO to AM18.
No
GO to AM4.

AM4 CHECK THE DRIVER SEAT CUSHION TED (Thermo-Electric Device) THERMISTOR

- Disconnect: Driver Seat Cushion TED (Thermo-Electric Device) C3035.

- Measure the resistance between driver seat cushion TED (Thermo-Electric Device) C3035 pin 5 and pin 8, component side. Note the ambient temperature and refer to the following table.

Temperature Resistance 0-10°C (32-50°F) 2,782-1,663 ohms 10-20°C (50-68°F) 1,837-1,140 ohms 20-30°C (68-86°F) 1,260-806 ohms 30-40°C (86-104°F) 893-570 ohms 40-50°C (104-122°F) 630-428 ohms

Is the resistance within the limits indicated?

Yes
REPAIR circuit VHS26 (VT) or RHS05 (YE/VT) for an open or 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 (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
No
INSTALL a new driver seat cushion TED (Thermo-Electric Device). REFER to 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 (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AM5 CONFIRM THE FAULT WHILE MONITORING THE DCSM (Dual Climate Controlled Seat Module) SEAT BACK THERMAL ELECTRIC DEVICE TEMPERATURE (BK_TEMP) AND SEAT CUSHION THERMAL ELECTRIC DEVICE TEMPERATURE (CSHTEMP) PIDs

- Set the driver seat to OFF.

- Enter the following diagnostic mode on the scan tool: Clear DTCs - DCSM (Dual Climate Controlled Seat Module).

- Enter the following diagnostic mode on the scan tool: DataLogger - DCSM (Dual Climate Controlled Seat Module).

- Monitor the DCSM (Dual Climate Controlled Seat Module) PIDs BK_TEMP and CSHTEMP.

- NOTE: A crushed seat cushion foam pad or a crushed climate controlled seat manifold may be the cause of the fault making it necessary to occupy the seat to recreate and identify the fault.
Attempt to recreate the fault. Start the vehicle and set the driver seat to HIGH heat for at least 15 minutes while occupying the seat.

Do the PIDs increase incrementally (gradually) and stay within 15°C (27°F) of each other?

Yes
The fault is not present at this time. The fault may have been set due to a past failure, incorrect use of the climate controlled seat system by repeated switching between heat and cool modes or due to excessive passenger compartment temperature. CLEAR the DTCs. REPEAT the self-test.
No
If the CSHTEMP PID increases incrementally and is greater than 15°C (27°F) of the BK_TEMP PID, GO to AM6.

If the CSHTEMP PID increases quickly (temperature "jumps" and does not increase incrementally) and is greater than 15°C (27°F) of the BK_TEMP PID, GO to AM16.

AM6 COMPARE OPERATION OF THE DRIVER AND PASSENGER SEATS

- With the engine running, set both front seats to HIGH cool.

- Note the airflow exhausting from the driver seat cushion TED (Thermo-Electric Device) and compare it to the airflow exhausting from the passenger seat cushion TED (Thermo-Electric Device).

- Carry out a wiggle test of the wire harnesses between the DCSM (Dual Climate Controlled Seat Module) and the driver seat cushion TED (Thermo-Electric Device) while monitoring blower operation of the TED (Thermo-Electric Device). The blower should operate consistently and not change speeds.

Is the airflow exhausting from the driver seat cushion TED (Thermo-Electric Device) comparable to the airflow exhausting from the passenger seat cushion TED (Thermo-Electric Device) with no change in operation when carrying out the wiggle test?

Yes
GO to AM7.
No
If the airflow exhausting from the driver seat cushion TED (Thermo-Electric Device) is not comparable to the airflow exhausting from the passenger seat cushion TED (Thermo-Electric Device), GO to AM8.

If the driver seat cushion TED (Thermo-Electric Device) blower operation changed while carrying out the wiggle test, IDENTIFY and REPAIR the wiring fault. CLEAR the DTCs. REPEAT the self-test.

AM7 COMPARE OPERATION OF THE DRIVER AND PASSENGER SEATS WHILE OCCUPIED

- Note the airflow exhausting from the driver seat cushion TED (Thermo-Electric Device) with the driver seat occupied and compare it to the airflow exhausting from the passenger seat cushion TED (Thermo-Electric Device) with the passenger seat occupied.

Is the airflow exhausting from the driver seat cushion TED (Thermo-Electric Device) comparable to the airflow exhausting from the passenger seat cushion TED (Thermo-Electric Device) ?

Yes
GO to AM16.
No
INSTALL a new driver seat cushion foam pad and/or climate controlled seat manifold. CLEAR the DTCs. REPEAT the self-test.

AM8 CHECK THE DRIVER SEAT CUSHION BLOWER FOR AN OBSTRUCTION OR RESTRICTED FILTER

- Ignition OFF.

- Inspect the blower of the driver seat cushion TED (Thermo-Electric Device) assembly for an obstruction or for a restricted filter.

Is the blower obstructed or the filter restricted?

Yes
REMOVE the obstruction or INSTALL a new filter. CLEAR the DTCs. REPEAT the self-test.
No
GO to AM9.

AM9 CHECK THE DRIVER SEAT CUSHION BLOWER SPEED CONTROL CIRCUIT FOR AN OPEN

- Depower the SRS (Supplemental Restraint System). Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of Restraints and Safety Systems &/or Air Bag Systems.

- Disconnect: Driver Seat Side Air Bag C3051 and Passenger Seat Side Air Bag C339.

- Disconnect: DCSM (Dual Climate Controlled Seat Module) C3265C.

- Disconnect: Driver Seat Cushion TED (Thermo-Electric Device) C3035.

- 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.

- Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3265C-11, circuit VHS18 (BN/GN), harness side and driver seat cushion TED (Thermo-Electric Device) C3035-7, circuit VHS18 (BN/GN), harness side.

Is the resistance less than 5 ohms?

Yes
GO to AM10.
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 (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AM10 CHECK THE DRIVER SEAT CUSHION BLOWER CIRCUIT FOR A SHORT TO VOLTAGE

- Ignition ON.

- Measure the voltage between DCSM (Dual Climate Controlled Seat Module) C3265C-15, circuit RHS03 (GY/OG), 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 (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
No
GO to AM11.

AM11 CHECK THE DRIVER SEAT CUSHION BLOWER CIRCUIT FOR A SHORT TO GROUND

- Ignition OFF.

- Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3265C-16, circuit CHS03 (GN/BN), harness side and ground.

Is the resistance greater than 10,000 ohms?

Yes
GO to AM12.
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 (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AM12 CHECK THE DRIVER SEAT CUSHION BLOWER CIRCUITS FOR AN OPEN

- Measure the resistance between:
- DCSM (Dual Climate Controlled Seat Module) C3265C-16, circuit CHS03 (GN/BN), harness side and driver seat cushion TED (Thermo-Electric Device) C3035-2, circuit CHS03 (GN/BN), harness side.

- DCSM (Dual Climate Controlled Seat Module) C3265C-15, circuit RHS03 (GY/OG), harness side and driver seat cushion TED (Thermo-Electric Device) C3035-4, circuit RHS03 (GY/OG), harness side.

Are the resistances less than 5 ohms?

Yes
GO to AM13.
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 (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AM13 CHECK THE DRIVER SEAT CUSHION BLOWER RESISTANCE

- 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 results in false readings and leads to incorrect identification of components that are not damaged.
Measure the resistance between driver seat cushion TED (Thermo-Electric Device) C3035 pin 2 and pin 4, component side.

Is the resistance between 4,000 ohms and 10,000 ohms?

Yes
GO to AM14.
No
INSTALL a new driver seat cushion TED (Thermo-Electric Device). REFER to 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 (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AM14 CHECK THE DRIVER SEAT CUSHION BLOWER SPEED CONTROL RESISTANCE

- 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 results in false readings and leads to incorrect identification of components that are not damaged.
Measure the resistance between driver seat cushion TED (Thermo-Electric Device) C3035 pin 7 and pin 4, component side.

Is the resistance between 240K ohms and 400K ohms?

Yes
GO to AM15.
No
INSTALL a new driver seat cushion TED (Thermo-Electric Device). REFER to 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 (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AM15 CHECK THE DRIVER SEAT CUSHION TED (Thermo-Electric Device) INSTALLATION AND FOR CRUSHED SEAT CUSHION

- Ignition OFF.

- Remove the driver seat. Refer to Seat- Front .

- Remove the driver seat cushion cover. Refer to Seat Cushion Cover- Front .

- Inspect the driver seat cushion for the following:
- Is the driver seat cushion TED (Thermo-Electric Device) correctly installed?

- Is the driver seat cushion seat cushion foam pad crushed or restricted?

- Is the driver seat cushion climate controlled seat manifold crushed or restricted?

Is the driver seat cushion TED (Thermo-Electric Device) correctly installed and are there no signs of damage to the foam pad and manifold?

Yes
INSTALL the driver seat cushion cover and seat and GO to AM18.
No
CORRECTLY install the driver seat cushion TED (Thermo-Electric Device) or INSTALL a new driver seat cushion foam pad and/or climate controlled seat manifold. CONNECT the battery ground cable. 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 (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AM16 CHECK THE DRIVER SEAT CUSHION TED (Thermo-Electric Device) THERMISTOR AND WIRING

- Ignition OFF.

- Depower the SRS (Supplemental Restraint System). Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of Restraints and Safety Systems &/or Air Bag Systems.

- Disconnect: Driver Seat Side Air Bag C3051 and Passenger Seat Side Air Bag C339.

- Disconnect: DCSM (Dual Climate Controlled Seat Module) 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.

- Measure the resistance between DCSM (Dual Climate Controlled Seat Module) C3265B-7, circuit VHS26 (VT), harness side and C3035B-8 circuit RHS05 (YE/VT), harness side. Note the ambient temperature and refer to the following table.

Temperature Resistance 0-10°C (32-50°F) 2,782-1,663 ohms 10-20°C (50-68°F) 1,837-1,140 ohms 20-30°C (68-86°F) 1,260-806 ohms 30-40°C (86-104°F) 893-570 ohms 40-50°C (104-122°F) 630-428 ohms

Is the resistance within the limits indicated?

Yes
GO to AM18.
No
GO to AM17.

AM17 CHECK THE DRIVER SEAT CUSHION TED (Thermo-Electric Device) THERMISTOR

- Measure the resistance between driver seat cushion TED (Thermo-Electric Device) C3035 pin 5 and pin 8, component side. Note the ambient temperature and refer to the following table.

Temperature Resistance 0-10°C (32-50°F) 2,782-1,663 ohms 10-20°C (50-68°F) 1,837-1,140 ohms 20-30°C (68-86°F) 1,260-806 ohms 30-40°C (86-104°F) 893-570 ohms 40-50°C (104-122°F) 630-428 ohms

Is the resistance between 0.9 and 10 ohms?

Yes
GO to AM21.
No
GO to AM20.

AM20 CHECK THE RESISTANCE OF THE DRIVER SEAT CUSHION TED (Thermo-Electric Device)

- Disconnect: Driver Seat Cushion TED (Thermo-Electric Device) C3035.

- Measure the resistance between driver seat cushion TED (Thermo-Electric Device) C3035 pin 1 and pin 3, component side.

Is the resistance between 0.9 and 10 ohms?

Yes
REPAIR circuit CHS02 (YE/BU) or RHS02 (BU/OG) for an open or 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 (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
No
INSTALL a new driver seat cushion TED (Thermo-Electric Device). REFER to 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 (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.

AM21 CHECK FOR CORRECT DCSM (Dual Climate Controlled Seat Module) OPERATION

- Inspect the DCSM (Dual Climate Controlled Seat Module) and driver seat cushion TED (Thermo-Electric Device) harness and component side connectors and the body harness-to-seat harness connectors for:
- corrosion

- damaged pins

- pushed-out pins

- Connect: All DCSM (Dual Climate Controlled Seat Module), TED (Thermo-Electric Device) and Body Harness-to-Seat Harness Connectors.

- Make sure the connectors are seated correctly.

- Start the engine.

- Set the driver seat to OFF.

- Enter the following diagnostic mode on the scan tool: Clear DTCs - DCSM (Dual Climate Controlled Seat Module).

- Attempt to recreate the fault. With the engine still running set the driver seat to HIGH heat for at least 15 minutes.

Is the concern still present?

Yes
INSTALL a new DCSM (Dual Climate Controlled Seat Module). REFER to Dual Climate Controlled Seat Module (DCSM) . REPEAT the self-test. TEST the system for normal operation.

DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C339.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.

DISCONNECT the battery ground cable. CONNECT driver seat side air bag module C3051 and passenger seat side air bag module C339.

REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.