DTC B2425 or B2430. GMC Truck Envoy

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 2008 🢒 Envoy - 2WD 🢒 Seats 🢒 Seat Heating and Cooling 🢒 DTC B2425 or B2430

Diagnostic Instructions

•	Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

•	Review Strategy Based Diagnosis for an overview of the diagnostic approach.

•	Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B2425: Driver Seat Heater Circuit

DTC B2430: Passenger Seat Heater Circuit

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Driver Seat Back Element Voltage Control	B2425	1	B2425	--
Driver Seat Cushion Element Voltage Control	B2425	1	B2425	--
Driver Seat Back and Cushion Element Low Reference Control	B2425	1	B2425	--
Passenger Seat Back Element Voltage Control	B2430	2	B2430	--
Passenger Seat Cushion Element Voltage Control	B2430	2	B2430	--
Passenger Seat Back and Cushion Element Low Reference Control	B2430	2	B2430	--
1. Driver heated seat inoperative. 2. Passenger heated seat inoperative.

The left and right heated seats are controlled by the memory seat module (MSM). When active, ground is applied to the seat cushion and back heater elements through a common low side drive low reference control circuit. Battery voltage is applied to each individual heater element by the MSM through separate high side drive control circuits. The heater element control circuits are pulse width modulated to B+ by the module in order to control the seat temperature by regulating the current flow through the heater elements. The module then monitors the current flow through the heating elements and the of rate change of the temperature sensors to verify correct heated seat operation.

Conditions for Running the DTC

•	The battery voltage must be between 9-16 volts.

•	Heated seat operation is enabled.

Conditions for Setting the DTC

•	One of the low side drive control circuits is shorted to voltage or ground.

•	One of the heater element voltage supply circuits is shorted to voltage or ground.

Action Taken When the DTC Sets

The seat module will disable heated seat operation.

Conditions for Clearing the DTC

•	This DTC will clear on current status after the condition for setting the fault is corrected.

•	The history DTC will clear after 100 consecutive fault-free ignition cycles have occurred.

Reference Information

Electrical Information Reference

•	Circuit Testing

•	Connector Repairs

•	Testing for Intermittent Conditions and Poor Connections

•	Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

B2425

Ignition OFF, disconnect the X3 harness connector at the MSM.
Test for infinite resistance between the control circuit terminal B12 and ground.

⇒	If less than the specified range, test the control circuits listed below for a short to ground:

•	Driver seat cushion and seat back terminal B12

•	Driver seat cushion circuit terminal B11

•	Driver seat back circuit terminal B10

Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal B12 and ground.

⇒	If the test lamp illuminates, test the control circuits listed below for a short to voltage:

•	Driver seat cushion and seat back terminal B12

•	Driver seat cushion circuit terminal B11

•	Driver seat back circuit terminal B10

If all circuits test normal, replace the MSM.

B2430

Ignition OFF, disconnect the X3 harness connector at the MSM.
Test for infinite resistance between the control circuit terminal B9 and ground.

⇒	If less than the specified range, test the control circuits listed below for a short to ground:

•	Passenger seat cushion and seat back terminal B9

•	Passenger seat cushion circuit terminal B8

•	Passenger seat back circuit terminal B7

Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal B9 and ground.

⇒	If the test lamp illuminates, test the control circuits listed below for a short to voltage:

•	Passenger seat cushion and seat back terminal B9

•	Passenger seat cushion circuit terminal B8

•	Passenger seat back circuit terminal B7

If all circuits test normal, replace the MSM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•	Driver or Passenger Seat Back Cushion Heater Replacement

•	Driver or Passenger Seat Cushion Heater Replacement

•	Control Module References for MSM replacement, programming, and setup