Diagnostic Routine AE
Diagnostic Routine AE
Diagnostic Overview
B272B
Refer to Wiring Diagram Set 119 for schematic and connector information Electrical Diagrams.
Normal Operation and Fault Conditions
DTC Fault Trigger Conditions
Pinpoint Test
NOTICE: When taking measurements at DCSM (Dual Climate Controlled Seat Module) 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 DTCs (Diagnostic Trouble Codes) and system failure. Touching the tip of these connector pins is recommended instead.
1. CHECK THE DCSM (Dual Climate Controlled Seat Module) FOR ON-DEMAND DTCs (Diagnostic Trouble Codes)
1. Start the vehicle and set the passenger seat to HIGH heat.
2. Using a scan tool, perform DCSM (Dual Climate Controlled Seat Module) self-test.
Was DTC (Diagnostic Trouble Code) B272B retrieved on-demand during the self-test?
2. CHECK THE PASSENGER SEAT BACKREST TED (Thermo-Electric Device) THERMISTOR CIRCUITS FOR A SHORT TO GROUND
1. Ignition OFF.
2. Depower the SRS (Supplemental Restraint System). REFER to Supplemental Restraint System (SRS) Depowering and Repowering - with Intelligent Access (IA) or REFER to Supplemental Restraint System (SRS) Depowering and Repowering - without Intelligent Access (IA) .
3. Disconnect: Passenger Seat Side Air Bag C339.
4. Disconnect: DCSM (Dual Climate Controlled Seat Module) C3265B.
5. Disconnect: Passenger Seat Backrest TED (Thermo-Electric Device) C3039.
6. 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 Disconnect .
7. Measure:
Are the resistances greater than 10,000 ohms?
3. CHECK THE PASSENGER SEAT BACKREST TED (Thermo-Electric Device) THERMISTOR AND WIRING
1. Connect: Passenger Seat Backrest TED (Thermo-Electric Device) C3039.
2. Measure:
Is the resistance within the limits indicated?
4. CHECK THE PASSENGER SEAT BACKREST TED (Thermo-Electric Device) THERMISTOR
1. Disconnect: Passenger Seat Backrest TED (Thermo-Electric Device) C3039.
2. Measure:
Is the resistance within the limits indicated?
5. CONFIRM THE FAULT WHILE MONITORING THE DCSM (Dual Climate Controlled Seat Module) SEAT BACK THERMAL ELECTRIC DEVICE TEMPERATURE (PBKTEMP) AND SEAT CUSHION THERMAL ELECTRIC DEVICE TEMPERATURE (PCSHTEMP) PIDs (Parameter Identifications)
1. Set the passenger seat to OFF.
2. Using a scan tool, clear DCSM (Dual Climate Controlled Seat Module) DTCs (Diagnostic Trouble Codes).
3. Using a scan tool, view DCSM (Dual Climate Controlled Seat Module) PIDs (Parameter Identifications).
- Seat Cushion TED (Thermo-Electric Device) Temperature (PCSHTEMP)
- Seat Back TED (Thermo-Electric Device) Temperature (PBKTEMP)
4. 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 seat to HIGH heat for at least 15 minutes while occupying the seat.
Do the PIDs (Parameter Identifications) increase incrementally (gradually) and stay within 15°C (27°F) of each other?
6. COMPARE OPERATION OF THE DRIVER AND PASSENGER SEATS
1. With the engine running, set both front seats to HIGH cool.
2. Note the airflow exhausting from the passenger seat backrest TED (Thermo-Electric Device) and compare it to the airflow exhausting from the driver seat backrest TED (Thermo-Electric Device).
3. Carry out a wiggle test of the wire harnesses between the DCSM (Dual Climate Controlled Seat Module) and the passenger 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 seat backrest TED (Thermo-Electric Device) comparable to the airflow exhausting from the driver seat backrest TED (Thermo-Electric Device) with no change in operation when carrying out the wiggle test?
7. COMPARE OPERATION OF THE DRIVER AND PASSENGER SEATS WHILE OCCUPIED
1. 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 seat backrest TED (Thermo-Electric Device) comparable to the airflow exhausting from the driver seat backrest TED (Thermo-Electric Device)?
8. CHECK THE PASSENGER SEAT BACKREST BLOWER FOR AN OBSTRUCTION OR RESTRICTED FILTER
1. Ignition OFF.
2. Inspect the blower of the passenger seat backrest TED (Thermo-Electric Device) assembly for an obstruction or for a restricted filter.
Is the blower obstructed or the filter restricted?
9. CHECK THE PASSENGER SEAT BACKREST BLOWER SPEED CONTROL CIRCUIT FOR AN OPEN
1. Depower the SRS (Supplemental Restraint System). REFER to Supplemental Restraint System (SRS) Depowering and Repowering - with Intelligent Access (IA) or REFER to Supplemental Restraint System (SRS) Depowering and Repowering - without Intelligent Access (IA) .
2. Disconnect: Passenger Seat Side Air Bag C339.
3. Disconnect: DCSM (Dual Climate Controlled Seat Module) C3265C.
4. Disconnect: Passenger Seat Backrest TED (Thermo-Electric Device) C3039.
5. 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 Disconnect .
6. Measure:
Is the resistance less than 3 ohms?
10. CHECK THE PASSENGER SEAT BACKREST BLOWER CIRCUIT FOR A SHORT TO VOLTAGE
1. Ignition ON.
2. Measure:
Is any voltage present?
11. CHECK THE PASSENGER SEAT BACKREST BLOWER CIRCUIT FOR A SHORT TO GROUND
1. Ignition OFF.
2. Measure:
Is the resistance greater than 10,000 ohms?
12. CHECK THE PASSENGER SEAT BACKREST BLOWER CIRCUITS FOR AN OPEN
1. Measure:
Are the resistances less than 3 ohms?
13. CHECK THE PASSENGER SEAT BACKREST BLOWER RESISTANCE
1. NOTICE: Connect the ohmmeter with the positive lead to pin 2 and the negative lead to pin 4 when measuring. Ohmmeter leads incorrectly connected can result in false readings and lead to incorrect identification of components that are not damaged.
Measure:
Is the resistance between 4,000 ohms and 10,000 ohms?
14. CHECK THE PASSENGER SEAT BACKREST BLOWER SPEED CONTROL RESISTANCE
1. NOTICE: Connect the ohmmeter with the positive lead to pin 7 and the negative lead to pin 4 when measuring. Ohmmeter leads incorrectly connected can result in false readings and lead to incorrect identification of components that are not damaged.
Measure:
Is the resistance between 240K ohms and 420K ohms?
15. CHECK THE PASSENGER SEAT BACKREST TED (Thermo-Electric Device) INSTALLATION AND FOR CRUSHED SEAT BACKREST
1. Ignition OFF.
2. Remove the seat. REFER to Seat .
3. Remove the seat cushion cover. REFER to Seat Backrest Cover .
4. Inspect the passenger seat backrest.
- Is the passenger seat backrest TED (Thermo-Electric Device) correctly installed?
- Is the passenger seat backrest seat backrest foam pad crushed or restricted?
- Is the passenger seat backrest climate controlled seat manifold crushed or restricted?
Is the TED (Thermo-Electric Device) correctly installed and are the foam pad and manifold free of damage?
16. CHECK THE PASSENGER SEAT BACKREST TED (Thermo-Electric Device) THERMISTOR AND WIRING
1. Ignition OFF.
2. Depower the SRS (Supplemental Restraint System). REFER to Supplemental Restraint System (SRS) Depowering and Repowering - with Intelligent Access (IA) or REFER to Supplemental Restraint System (SRS) Depowering and Repowering - without Intelligent Access (IA) .
3. Disconnect: Passenger Seat Side Air Bag C339.
4. Disconnect: DCSM (Dual Climate Controlled Seat Module) C3265B.
5. 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 Disconnect .
6. Measure:
Is the resistance within the limits indicated?
17. CHECK THE PASSENGER SEAT BACKREST TED (Thermo-Electric Device) THERMISTOR
1. Measure:
Is the resistance within the limits indicated?
18. CHECK THE PASSENGER SEAT BACKREST TED (Thermo-Electric Device) HEATING/COOLING CIRCUITRY CURRENT DRAW
1. Connect: All DCSM (Dual Climate Controlled Seat Module), TED (Thermo-Electric Device) and body harness-to-seat harness connectors.
2. 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.
3. 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 IDS (Integrated Diagnostic System). If these are unavailable, the inductive current probe feature from a battery tester may be substituted.
4. Place an inductive current probe around circuit CHS06 (BU/BN) near DCSM (Dual Climate Controlled Seat Module) C3265A-C and monitor the current draw.
5. Start the vehicle and set the passenger seat to HIGH heat.
Is the current draw less than 11 amps?
19. CHECK RESISTANCE OF THE PASSENGER SEAT BACKREST TED (Thermo-Electric Device) AND WIRING
1. Ignition OFF.
2. Disconnect: DCSM (Dual Climate Controlled Seat Module) C3265A.
3. Measure:
Is the resistance between 0.9 and 10 ohms?
20. CHECK THE RESISTANCE OF THE PASSENGER SEAT BACKREST TED (Thermo-Electric Device)
1. Disconnect: Passenger Seat Backrest TED (Thermo-Electric Device) C3039.
2. Measure:
Is the resistance between 0.9 and 10 ohms?
21. CHECK FOR CORRECT DCSM (Dual Climate Controlled Seat Module) OPERATION
1. Inspect the DCSM (Dual Climate Controlled Seat Module) and passenger seat backrest TED (Thermo-Electric Device) harness and component side connectors and the body harness-to-seat harness connectors for:
2. corrosion
3. damaged pins
4. pushed-out pins
5. Connect: All DCSM (Dual Climate Controlled Seat Module), TED (Thermo-Electric Device) and Body Harness-to-Seat Harness Connectors.
6. Make sure the connectors are seated correctly.
7. Start the engine.
8. Set the passenger seat to OFF.
9. Enter the following diagnostic mode on the scan tool: Clear DTCs (Diagnostic Trouble Codes) - DCSM (Dual Climate Controlled Seat Module).
10. Attempt to recreate the fault. With the engine still running set the passenger seat to HIGH heat for at least 15 minutes.
Is the concern still present?
22. CHECK FOR SRS (Supplemental Restraint System) DTCs (Diagnostic Trouble Codes)
1. WARNING: Turn the ignition OFF and wait one minute to deplete the backup power supply. Failure to follow this instruction may result in serious personal injury or death in the event of an accidental deployment.
Ignition OFF.
2. Connect: Passenger Seat Side Air Bag C339.
3. Connect: DCSM (Dual Climate Controlled Seat Module) C3265A, C3265B or C3265C (if previously disconnected).
4. Connect: Passenger Seat Backrest TED (Thermo-Electric Device) C3039 (if previously disconnected).
5. Ignition ON.
6. Using a scan tool, clear the RCM (Restraints Control Module) DTCs (Diagnostic Trouble Codes).
7. Cycle the ignition OFF then ON.
8. Using a scan tool, perform RCM (Restraints Control Module) self-test.
Are any RCM (Restraints Control Module) DTCs (Diagnostic Trouble Codes) retrieved during self-test?
