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Chevrolet Silverado / GMC Sierra. Manual - part 2751
If greater than the specified range, test the signal circuit for a short to voltage. If the
circuit tests normal, replace the MSM.
If less than the specified range, test the signal circuit for a short to voltage. If the
circuit tests normal, replace the MSM.
6. If all circuits test normal, replace the MSM.
B2170
1. Ignition OFF, disconnect the X2, X5 harness connectors at the MSM.
2. Test for 850-300k ohms between the signal circuit terminal 2 X5 and the low reference
circuit terminal 6 X2.
If greater than the specified range, test the signal circuit and low reference circuit for a
short to voltage or an open/high resistance. If the circuit tests normal, replace the seat
cushion heater element.
If less than the specified range, test for a short between the signal and low reference
circuits. If the circuit tests normal, replace the seat cushion heater element.
3. Connect the X2, X5 harness connectors at the MSM.
4. Disconnect the harness connector at the seat cushion heater element.
5. Ignition ON, test for 4.8-5.2 volts between the temperature sensor signal circuit terminal C
and ground.
If greater than the specified range, test the signal circuit for a short to voltage. If the
circuit tests normal, replace the MSM.
If less than the specified range, test the signal circuit for a short to voltage. If the
circuit tests normal, replace the MSM.
6. If all circuits test normal, replace the MSM.
Repair Procedures
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Driver Seat and Passenger Seat Cushion Heater Replacement
Control Module References for the MSM replacement, setup, and programming
DTC B1935 OR B2180
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Seat Heating and Cooling - Cab & Chassis Sierra, Cab & Chassis Silverado,
Sierra & Silverado
Review Strategy Based Diagnosis for an overview of the diagnostic approach.
Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptors
DTC B1935 04
Left Seat Back Heater Circuit Open
DTC B1935 0A
Left Seat Back Heater Circuit Rate of Change Below Threshold
DTC B1935 0B
Left Seat Back Heater Circuit Current Above Threshold
DTC B1935 0C
Left Seat Back Heater Circuit Current Below Threshold
DTC B1935 0D
Left Seat Back Heater Circuit Resistance Above Threshold
DTC B1935 0E
Left Seat Back Heater Circuit Resistance Below Threshold
DTC B1935 1F
Left Seat Back Heater Circuit Intermittent
DTC B2180 04
Right Seat Back Heater Circuit Open
DTC B2180 0A
Right Seat Back Heater Circuit Rate of Change Below Threshold
DTC B2180 0B
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Seat Heating and Cooling - Cab & Chassis Sierra, Cab & Chassis Silverado,
Sierra & Silverado
Right Seat Back Heater Circuit Current Above Threshold
DTC B2180 0C
Right Seat Back Heater Circuit Current Below Threshold
DTC B2180 0D
Right Seat Back Heater Circuit Resistance Above Threshold
DTC B2180 0E
Right Seat Back Heater Circuit Resistance Below Threshold
DTC B2180 1F
Right Seat Back Heater Circuit Intermittent
Diagnostic Fault Information
Circuit
Short to
Ground
Open/High
Resistance
Short to
Voltage
Signal
Performance
Left Heated Seat Cushion
Element Supply Voltage
B2508 02
B2425 0C
B2425 0D
B2508 01
-
Left Heated Seat Cushion
Element Control
B2508 02
B2425 0C
B2425 0D
B2508 01
-
Left Heated Seat Cushion
Temperature Sensor Signal
B1925 02
B1925 05
B2425 04
B2425 1F
B1925 05
B2425 04
B2425 1F
-
Left Heated Seat Cushion
Temperature Low Reference
-
B1925 05
B2425 04
B2425 1F
-
-
Right Heated Seat Cushion
Element Supply Voltage
B2508 02
B2430 0C
B2430 0D
B2508 01
-
Right Heated Seat Cushion
Element Control
B2508 02
B2430 0C
B2430 0D
B2508 01
-
Right Heated Seat Cushion
Temperature Sensor Signal
B2170 02
B2170 05
B2430 04
B2430 1F
B2170 05
B2430 04
B2430 1F
-
B2170 05
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Seat Heating and Cooling - Cab & Chassis Sierra, Cab & Chassis Silverado,
Sierra & Silverado
Circuit/System Description
When the heated seat function is active, the Memory Seat Module (MSM) supplies battery
voltage through the element supply voltage circuit to the seat heater elements. The module
controls the seat temperature by providing a PWM ground through the heated seat element
control circuit to the seat heater elements. The module then monitors the current flow through the
heating element and the temperature sensor rate of change to verify correct operation.
Conditions for Running the DTC
The MSM must be powered and the heated seat must be enabled.
Conditions for Setting the DTC
B1935 04, B2180 04
The module does not detect a temperature change within 210 seconds.
B1935 0A, B2180 0A
The module detects that the set point temperature has not been reached within 8.5 minutes.
B1935 0B, B1935 0E, B2180 0B, B2180 0E
By measuring output current, the module calculates that the heating element resistance is below
the minimum resistance.
B1935 0C, B1935 0D, B2180 0C, B2180 0D
By measuring output current, the module calculates that the heating element resistance is above
the maximum resistance.
B1935 1F, B2180 1F
The temperature sensor voltage is erratic or changes suddenly.
Action Taken When the DTC Sets
The heated seat back function for the affected seat will be disabled.
Conditions for Clearing the DTC
Right Heated Seat Cushion
Temperature Low Reference
-
B2430 04
B2430 1F
-
-
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Seat Heating and Cooling - Cab & Chassis Sierra, Cab & Chassis Silverado,
Sierra & Silverado
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