Pinpoint Test BN: DTC B272B
Seats
Pinpoint Test BN: DTC B272B
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 B272B (Passenger Back Over-Temp Detected)- For heat mode, if the passenger seat backrest TED (Thermo-Electric Device) temperature exceeds 110°C (230°F) continuously for more than 4 seconds in any heat mode, the DCSM (Dual Climate Controlled Seat Module) turns off the TED (Thermo-Electric Device) and enters a fan only state to recover from the over-temperature condition (recovery mode). If the TED (Thermo-Electric Device) temperature does not recover after 30 seconds, the DTC will set and the seat is disabled. If the TED (Thermo-Electric Device) does recover, the TED (Thermo-Electric Device) 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 B272B (Passenger Back Over-Temp Detected)- For cool mode, if the passenger seat backrest TED (Thermo-Electric Device) temperature exceeds 65°C (149°F) continuously for more than 4 seconds in any cool mode, the DCSM (Dual Climate Controlled Seat Module) turns off the TED (Thermo-Electric Device) and enters a fan only state to recover from the over-temperature condition (recovery mode). If the TED (Thermo-Electric Device) temperature does not recover after 5 minutes, the DTC will set and the seat is disabled. If the TED (Thermo-Electric Device) does recover, the TED (Thermo-Electric Device) 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 backrest TED (Thermo-Electric Device) filter
- Crushed or restricted backrest foam pad
- Backrest TED (Thermo-Electric Device) assembly
- PCSM-2 (Passenger Climate Controlled Seat Module - 2)
PINPOINT TEST BN : DTC B272B
NOTICE: When taking measurements at PCSM-2 (Passenger Climate Controlled Seat Module - 2) 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.
BN1 CHECK THE PCSM-2 (Passenger Climate Controlled Seat Module - 2) FOR ON-DEMAND DTCs
- Start the vehicle and set the passenger side rear seat to HIGH heat.
- Enter the following diagnostic mode on the scan tool: Self Test- PCSM-2 (Passenger Climate Controlled Seat Module - 2).
Was DTC B272B retrieved on-demand during the self-test?
Yes
GO to BN2.
No
GO to BN5.
BN2 CHECK THE PASSENGER SIDE REAR SEAT BACKREST TED (Thermo-Electric Device) THERMISTOR CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: PCSM-2 (Passenger Climate Controlled Seat Module - 2) C3365B.
- Disconnect: Passenger Side Rear Seat Backrest TED (Thermo-Electric Device) C3361.
- Measure the resistance between:
- PCSM-2 (Passenger Climate Controlled Seat Module - 2) C3365B-4, circuit VHS64 (BN/VT), harness side and ground.
- PCSM-2 (Passenger Climate Controlled Seat Module - 2) C3365B-5, circuit RHS62 (GY), harness side and ground.
Are the resistances greater than 10,000 ohms?
Yes
GO to BN3.
No
REPAIR the circuit(s). CLEAR the DTCs. REPEAT the self-test.
BN3 CHECK THE PASSENGER SIDE REAR SEAT BACKREST TED (Thermo-Electric Device) THERMISTOR AND WIRING
- Connect: Passenger Side Rear Seat Backrest TED (Thermo-Electric Device) C3361.
- Measure the resistance between PCSM-2 (Passenger Climate Controlled Seat Module - 2) C3365B-4, circuit VHS64 (BN/VT), harness side and PCSM-2 (Passenger Climate Controlled Seat Module - 2) C3365B-5, circuit RHS62 (GY), 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 BN18.
No
GO to BN4.
BN4 CHECK THE PASSENGER SIDE REAR SEAT BACKREST TED (Thermo-Electric Device) THERMISTOR
- Disconnect: Passenger Side Rear Seat Backrest TED (Thermo-Electric Device) C3361.
- Measure the resistance between passenger side rear seat backrest TED (Thermo-Electric Device) C3361 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 VHS64 (BN/VT) or RHS62 (GY) for an open or high resistance. CLEAR the DTCs. REPEAT the self-test.
No
INSTALL a new passenger side rear seat backrest TED (Thermo-Electric Device). REFER to Seat Backrest Thermo-Electric Device - Second Row . CLEAR the DTCs. REPEAT the self-test.
BN5 CONFIRM THE FAULT WHILE MONITORING THE PCSM-2 (Passenger Climate Controlled Seat Module - 2) SEAT BACK THERMAL ELECTRIC DEVICE TEMPERATURE (PBKTEMP) AND SEAT CUSHION THERMAL ELECTRIC DEVICE TEMPERATURE (PCSHTEMP) PIDs
- Set the passenger side rear seat to OFF.
- Enter the following diagnostic mode on the scan tool: Clear DTCs - PCSM-2 (Passenger Climate Controlled Seat Module - 2).
- Enter the following diagnostic mode on the scan tool: DataLogger - PCSM-2 (Passenger Climate Controlled Seat Module - 2).
- Monitor the PCSM-2 (Passenger Climate Controlled Seat Module - 2) PIDs PBKTEMP and PCSHTEMP.
- NOTE: A crushed seat backrest 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 passenger side rear 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
Fault not present at this time. 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 PBKTEMP PID increases incrementally and is greater than 15°C (27°F) of the PCSHTEMP PID, GO to BN6.
If the PBKTEMP PID increases quickly (temperature "jumps" and does not increase incrementally) and is greater than 15°C (27°F) of the PCSHTEMP PID, GO to BN16.
BN6 COMPARE OPERATION OF THE DRIVER AND PASSENGER SIDE REAR SEATS
- With the engine running, set both rear seats to HIGH cool.
- Note the airflow exhausting from the passenger side rear seat backrest TED (Thermo-Electric Device) and compare it to the airflow exhausting from the driver side rear seat backrest TED (Thermo-Electric Device).
- Carry out a wiggle test of the wire harnesses between the PCSM-2 (Passenger Climate Controlled Seat Module - 2) and the passenger side rear seat backrest 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 passenger side rear seat backrest TED (Thermo-Electric Device) comparable to the airflow exhausting from the driver side rear seat backrest
TED (Thermo-Electric Device) with no change in operation when carrying out the wiggle test?
Yes
GO to BN7.
No
If the airflow exhausting from the passenger side rear seat backrest TED (Thermo-Electric Device) is not comparable to the airflow exhausting from the driver side rear seat backrest TED (Thermo-Electric Device), GO to BN8.
If the passenger side rear seat backrest 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.
BN7 COMPARE OPERATION OF THE DRIVER AND PASSENGER SEATS WHILE OCCUPIED
- Note the airflow exhausting from the passenger seat backrest TED (Thermo-Electric Device) with the passenger seat occupied and compare it to the airflow exhausting from the driver seat backrest TED (Thermo-Electric Device) with the driver seat occupied.
Is the airflow exhausting from the passenger side rear seat backrest TED (Thermo-Electric Device) comparable to the airflow exhausting from the driver side rear seat backrest TED (Thermo-Electric Device)?
Yes
GO to BN16.
No
INSTALL a new passenger side rear seat backrest foam pad and/or climate controlled seat manifold. CLEAR the DTCs. REPEAT the self-test.
BN8 CHECK THE PASSENGER SIDE REAR SEAT BACKREST BLOWER FOR AN OBSTRUCTION OR RESTRICTED FILTER
- Ignition OFF.
- Inspect the blower of the passenger side rear seat backrest 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 BN9.
BN9 CHECK THE PASSENGER SIDE REAR SEAT BACKREST BLOWER SPEED CONTROL CIRCUIT FOR AN OPEN
- Disconnect: PCSM-2 (Passenger Climate Controlled Seat Module - 2) C3365C.
- Disconnect: Passenger Side Rear Seat Backrest TED (Thermo-Electric Device) C3361.
- Measure the resistance between PCSM-2 (Passenger Climate Controlled Seat Module - 2) C3365C-4, circuit VHS64 (BN/VT), harness side and passenger seat backrest TED (Thermo-Electric Device) C3361-7, circuit VHS64 (BN/VT), harness side.
Is the resistance less than 5 ohms?
Yes
GO to BN10.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
BN10 CHECK THE PASSENGER SIDE REAR SEAT BACKREST BLOWER CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition ON.
- Measure the voltage between PCSM-2 (Passenger Climate Controlled Seat Module - 2) C3365C-7, circuit RHS63 (WH/GN), harness side and ground.
Is any voltage present?
Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
No
GO to BN11.
BN11 CHECK THE PASSENGER SIDE REAR SEAT BACKREST BLOWER CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between PCSM-2 (Passenger Climate Controlled Seat Module - 2) C3365C-8, circuit CHS63 (VT), harness side and ground.
Is the resistance greater than 10,000 ohms?
Yes
GO to BN12.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
BN12 CHECK THE PASSENGER SIDE REAR SEAT BACKREST BLOWER CIRCUITS FOR AN OPEN
- Measure the resistance between:
- PCSM-2 (Passenger Climate Controlled Seat Module - 2) C3365C-8, circuit CHS63 (VT), harness side and passenger seat backrest TED (Thermo-Electric Device) C3361-2, circuit CHS63 (VT), harness side.
- PCSM-2 (Passenger Climate Controlled Seat Module - 2) C3365C-7, circuit RHS63 (WH/GN), harness side and passenger seat backrest TED (Thermo-Electric Device) C3361-4, circuit RHS63 (WH/GN), harness side.
Are the resistances less than 5 ohms?
Yes
GO to BN13.
No
REPAIR the circuit(s). CLEAR the DTCs. REPEAT the self-test.
BN13 CHECK THE PASSENGER SIDE REAR SEAT BACKREST 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 passenger side rear seat backrest TED (Thermo-Electric Device) C3361 pin 2 and pin 4, component side.
Is the resistance between 4,000 ohms and 10,000 ohms?
Yes
GO to BN14.
No
INSTALL a new passenger side rear seat backrest TED (Thermo-Electric Device). REFER to Seat Backrest Thermo-Electric Device - Second Row . CLEAR the DTCs. REPEAT the self-test.
BN14 CHECK THE PASSENGER SIDE REAR SEAT BACKREST 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 passenger side rear seat backrest TED (Thermo-Electric Device) C3361 pin 7 and pin 4, component side.
Is the resistance between 240K ohms and 400K ohms?
Yes
GO to BN15.
No
INSTALL a new passenger side rear seat backrest TED (Thermo-Electric Device). REFER to Seat Backrest Thermo-Electric Device - Second Row . CLEAR the DTCs. REPEAT the self-test.
BN15 CHECK THE PASSENGER SIDE REAR SEAT BACKREST TED (Thermo-Electric Device) INSTALLATION AND FOR CRUSHED SEAT BACKREST
- Ignition OFF.
- Remove the passenger side rear seat backrest cover. Refer to Seat Backrest Cover- Second Row, 40 Percent or Seat Backrest Cover- Second Row, 60 Percent Seat Backrest Cover- Front .
- Inspect the seat backrest for the following:
- Is the seat backrest TED (Thermo-Electric Device) correctly installed?
- Is the seat backrest foam pad crushed or restricted?
- Is the seat backrest climate controlled seat manifold crushed or restricted?
Is the passenger side rear seat backrest TED (Thermo-Electric Device) correctly installed and are there no signs of damage to the foam pad and manifold?
Yes
INSTALL the passenger side rear seat backrest cover and seat and GO to BN18.
No
CORRECTLY install the passenger side rear seat backrest TED (Thermo-Electric Device) or INSTALL a new passenger side rear seat backrest foam pad and/or climate controlled seat manifold.
BN16 CHECK THE PASSENGER SIDE REAR SEAT BACKREST TED (Thermo-Electric Device) THERMISTOR AND WIRING
- Ignition OFF.
- Disconnect: PCSM-2 (Passenger Climate Controlled Seat Module - 2) C3365B.
- Measure the resistance between PCSM-2 (Passenger Climate Controlled Seat Module - 2) C3365B-4, circuit VHS62 (GN/WH), harness side and C3365B-5 circuit RHS62 (GY), 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 BN18.
No
GO to BN17.
BN17 CHECK THE PASSENGER SIDE REAR SEAT BACKREST TED (Thermo-Electric Device) THERMISTOR
- Measure the resistance between passenger side rear seat backrest TED (Thermo-Electric Device) C3361 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 VHS62 (GN/WH) or RHS62 (GY) for an open or high resistance. CLEAR the DTCs. REPEAT the self-test.
No
INSTALL a new TED (Thermo-Electric Device). REFER to Seat Backrest Thermo-Electric Device - Second Row . CLEAR the DTCs. REPEAT the self-test.
BN18 CHECK THE PASSENGER SIDE REAR SEAT BACKREST TED (Thermo-Electric Device) HEATING/COOLING CIRCUITRY CURRENT DRAW
- Connect: All PCSM-2 (Passenger Climate Controlled Seat Module - 2), TED (Thermo-Electric Device) and Body Harness-to-Seat Harness Connectors.
- NOTICE: It may be necessary to open the seat wire harness conduit to allow placing the inductive current probe around the circuit as described in the following step. Care must be taken when opening up the wire harness so as not to damage any wiring or connectors. Do not damage any wiring or induce stress on any wiring or connectors. Close up the wire harness once repairs to the seat are complete.
NOTE: Use a commercially available inductive current probe (such as Electronic Specialties Current Probe/Multimeter 685 or a Fluke I410 [used with a digital multimeter]) or the low current probe from the Vehicle Measurement Module available for use with Integrated Diagnostic System (IDS). If these are unavailable, the inductive current probe feature from a battery tester may be substituted.
Place an inductive current probe around circuit CHS44 (GN/VT) near PCSM-2 (Passenger Climate Controlled Seat Module - 2) C3305A-C and monitor the current draw.
- Start the vehicle and set the passenger seat to HIGH heat.
Is the current draw less than 11 amps?
Yes
GO to BN19.
No
INSTALL a new passenger side rear seat backrest TED (Thermo-Electric Device). REFER to Seat Backrest Thermo-Electric Device - Second Row . CLEAR the DTCs. REPEAT the self-test.
BN19 CHECK RESISTANCE OF THE PASSENGER SIDE REAR SEAT BACKREST TED (Thermo-Electric Device) AND WIRING
- Ignition OFF.
- Disconnect: PCSM-2 (Passenger Climate Controlled Seat Module - 2) C3365A.
- Measure the resistance between PCSM-2 (Passenger Climate Controlled Seat Module - 2) C3365A-C circuit CHS44 (GN/VT), harness side and C3365A-D, circuit RHS44 (BU/WH), harness side.
Is the resistance between 0.9 and 10 ohms?
Yes
GO to BN21.
No
GO to BN20.
BN20 CHECK THE RESISTANCE OF THE PASSENGER SIDE REAR SEAT BACKREST TED (Thermo-Electric Device)
- Disconnect: Passenger Side Rear Seat Backrest TED (Thermo-Electric Device) C3361.
- Measure the resistance between passenger side rear seat backrest TED (Thermo-Electric Device) C3361 pin 1 and pin 3, component side.
Is the resistance between 0.9 and 10 ohms?
Yes
REPAIR circuit CHS44 (GN/VT) or RHS44 (BU/WH) for an open or high resistance. CLEAR the DTCs. REPEAT the self-test.
No
INSTALL a new passenger seat backrest TED (Thermo-Electric Device). REFER to Seat Backrest Thermo-Electric Device - Second Row .
CLEAR the DTCs. REPEAT the self-test.
BN21 CHECK FOR CORRECT PCSM-2 (Passenger Climate Controlled Seat Module - 2) OPERATION
- Inspect the PCSM-2 (Passenger Climate Controlled Seat Module - 2) and passenger side rear seat backrest 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 PCSM-2 (Passenger Climate Controlled Seat Module - 2), TED (Thermo-Electric Device) and Body Harness-to-Seat Harness Connectors.
- Make sure the connectors are seated correctly.
- Start the engine.
- Set the passenger side rear seat to OFF.
- Enter the following diagnostic mode on the scan tool: Clear DTCs - PCSM-2 (Passenger Climate Controlled Seat Module - 2).
- Attempt to recreate the fault. With the engine still running set the passenger side rear seat to HIGH heat for at least 15 minutes.
Is the concern still present?
Yes
INSTALL a new PCSM-2 (Passenger Climate Controlled Seat Module - 2). REFER to Passenger Climate - Controlled Seat Module (PCSM-2) .
REPEAT the self-test. TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.