Pinpoint Test N: The Heated Seat Is Inoperative/Does Not Operate Correctly - Driver
Seats
Pinpoint Test N: The Heated Seat is Inoperative/Does Not Operate Correctly - Driver
Refer to Wiring Diagram Set 119, Climate Controlled Seats for schematic and connector information Electrical Diagrams.
Normal Operation
The engine must be running for the heated seat system to operate. The driver and passenger heated seat buttons are integral to the Front Controls Interface Module (FCIM) or are selected from the touchscreen interface. When the heated seat button is pressed on the touchscreen interface, the Accessory Protocol Interface Module (APIM) sends the request message to the FCIM (Front Controls Interface Module) over the Infotainment Controller Area Network (I-CAN). When a heated seat button is pressed on the FCIM (Front Controls Interface Module) or a heated seat request message has been received from the APIM (Accessory Protocol Interface Module), the FCIM (Front Controls Interface Module) sends the request message to the Instrument Panel Cluster (IPC) over the I-CAN (Infotainment Controller Area Network). The IPC (Instrument Panel Cluster) sends the message to the Body Control Module (BCM) over the High Speed Controller Area Network (HS-CAN). The message is then sent to the HVAC module over the Medium Speed Controller Area Network (MS-CAN). Upon receiving the request, the HVAC module supplies voltage to the appropriate driver and/or passenger seat cushion and backrest heater mats, which are connected in series. The driver and passenger heater mats share a common ground circuit. Temperature is maintained by the HVAC module using a sensor contained within the cushion heater mat. The HVAC module supplies a reference voltage to the temperature sensor and monitors the return signal from the temperature sensor for controlling current flow to the heater mats. The HVAC module remains on, heating the seat and maintaining temperature until commanded off from the FCIM (Front Controls Interface Module) or touchscreen interface (or until the ignition is turned OFF).
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Heater mat
- FCIM (Front Controls Interface Module)
- HVAC module
PINPOINT TEST N : THE HEATED SEAT IS INOPERATIVE/DOES NOT OPERATE CORRECTLY - DRIVER
WARNING: Never install heated seat parts not intended for use on this vehicle. Parts released for other model years or vehicle lines are not compatible even if they appear visually and physically similar. Installing incorrect parts will result in heated seat system performance outside design specification. Failure to follow this instruction may result in serious personal injury.
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.
N1 CHECK FOR HVAC DTCs
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self Test- HVAC module.
Were any DTCs retrieved during the self-tests?
Yes
For DTCs B1034:11, B1034:13, B1038:11 or B1038:12, GO to N3.
For all other DTCs, REFER to the HVAC Module DTC Chart to diagnose the HVAC module fault Seats.
No
If equipped with a touchscreen interface, GO to N3. If not equipped with a touchscreen interface, GO to N2.
N2 CHECK THE FCIM (Front Controls Interface Module) HEATED SEAT CONTROL SWITCH (CC_SW_D_HSEATS) PID
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: DataLogger- FCIM (Front Controls Interface Module) PID: CC_SW_D_HSEATS.
- Operate the driver heated seat control switch button while monitoring the CC_SW_D_HSEATS states.
Do the PID states agree?
Yes
GO to N3.
No
INSTALL a new FCIM (Front Controls Interface Module).
N3 CHECK THE HEATER ELEMENT POWER CIRCUIT FOR AN OPEN OR 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 C328.
- Disconnect: HVAC Module C228B.
- Disconnect: Driver Cushion Heater Mat C3283.
- 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:
- driver seat cushion heater mat C3283-1, circuit CHS02 (YE/BU), harness side and ground.
- driver seat cushion heater mat C3283-1, circuit CHS02 (YE/BU), harness side and HVAC module C228B-16, circuit CHS02 (YE/BU), harness side.
Is the resistance greater than 10,000 ohms between the driver seat cushion heater mat and ground; and less than 5 ohms between the driver seat cushion heater mat and the HVAC module?
Yes
GO to N4.
No
REPAIR the circuit. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT driver seat side air bag module C328.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
N4 CHECK THE HEATED SEAT TEMPERATURE SENSOR CIRCUIT FOR AN OPEN OR SHORT TO GROUND
- Measure the resistance between:
- driver seat cushion heater mat C3283-2, circuit VHS26 (VT), harness side and ground.
- driver seat cushion heater mat C3283-2, circuit VHS26 (VT), harness side and HVAC module C228B-30, circuit VHS26 (VT), harness side.
Is the resistance greater than 10,000 ohms between the driver seat cushion heater mat and ground and less than 5 ohms between the driver seat cushion heater mat and the HVAC module?
Yes
GO to N5.
No
REPAIR the circuit. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT driver seat side air bag module C328.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
N5 CHECK THE HEATED SEAT TEMPERATURE SENSOR RETURN CIRCUIT FOR AN OPEN OR SHORT TO GROUND
- Disconnect: HVAC Module C228A.
- Measure the resistance between:
- driver seat cushion heater mat C3283-3, circuit RH111 (GY/BU), harness side and ground.
- driver seat cushion heater mat C3283-3, circuit RH111 (GY/BU), harness side and HVAC module C228A-23, circuit RH111 (GY/BU), harness side.
Is the resistance greater than 10,000 ohms between the driver seat cushion heater mat and ground and less than 5 ohms between the driver seat cushion heater mat and the HVAC module?
Yes
GO to N6.
No
REPAIR the circuit. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT driver seat side air bag module C328.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
N6 CHECK THE HEATED SEAT CIRCUITS FOR A SHORT TO VOLTAGE
- Ignition ON.
- Measure the voltage between the following driver seat cushion heater mat C3283 pins, harness side and ground:
Connector - Pin Circuit C3283-1 CHS02 (YE/BU) C3283-2 VHS26 (VT) C3283-3 RH111 (GY/BU)
Is voltage present on any circuits?
Yes
REPAIR the affected circuit. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT driver seat side air bag module C328.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
No
GO to N7.
N7 CHECK THE HEATER ELEMENT GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Measure the resistance between driver seat cushion heater mat C3283-4, circuit GD145 (BK/BU), harness side and ground.
Is the resistance less than 5 ohms?
Yes
GO to N8.
No
REPAIR the circuit. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT driver seat side air bag module C328.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
N8 CHECK CUSHION HEATED SEAT MAT FOR AN OPEN AND A SHORT TO GROUND
- Disconnect: Driver Seat Cushion Heater Mat to Driver Seat Backrest Heater Mat Connector.
- Measure the resistance between:
- driver seat cushion heater mat C3283-1, component side and ground.
- driver seat cushion heater mat C3283-1, component side and driver seat cushion heater mat to driver seat backrest heater mat connector pin 1, cushion side.
Is the resistance greater than 10,000 ohms between the driver seat cushion heater mat and ground; and between 1.2 and 2.2 ohms between the driver seat cushion heater mat to driver seat backrest heater mat?
Yes
GO to N9.
No
INSTALL a new cushion heater mat. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT driver seat side air bag module C328.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
N9 CHECK BACKREST HEATED SEAT MAT FOR AN OPEN AND A SHORT TO GROUND
- Measure the resistance between:
- driver seat backrest heater mat connector pin 2, component side and ground.
- driver seat backrest heater mat connector pin 1 and pin 2, component side.
Is the resistance greater than 10,000 ohms between the driver seat backrest heater mat and ground; and between 1.2 and 2.2 ohms between the driver seat backrest heater mat pins?
Yes
GO to N10.
No
INSTALL a new backrest heater mat. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT driver seat side air bag module C328.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
N10 CHECK CIRCUIT BETWEEN BACKREST AND CUSHION HEATER MAT
- Measure the resistance between driver seat cushion heater mat C3283-4, component side and driver seat cushion heater mat to driver seat backrest heater mat connector pin 2, cushion side.
Is the resistance less than 5 ohms?
Yes
GO to N11.
No
INSTALL a new seat cushion heater mat. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT driver seat side air bag module C328.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
N11 CHECK THE HEATED SEAT TEMPERATURE SENSOR AND CIRCUITS FOR AN OPEN AND A SHORT TO GROUND
- Measure the resistance between:
- driver seat cushion heater mat C3283 pin 2 and pin 3, component side.
- driver seat cushion heater mat C3283 pin 2, component side and ground.
Is the resistance between 725 ohms and 170,000 ohms between driver seat cushion heater mat pins; and greater than 10,000 ohms between driver seat cushion heater mat and ground?
Yes
INSTALL a new HVAC module. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT driver seat side air bag module C328.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.
No
INSTALL a new seat cushion heater mat. TEST the system for normal operation.
DISCONNECT the battery ground cable.
CONNECT driver seat side air bag module C328.
REPOWER the SRS (Supplemental Restraint System). REFER to Restraints and Safety Systems &/or Air Bag Systems.