GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2004 🢒 Envoy - 2WD 🢒 DTC 🢒 DTC B3745

Circuit Description

The endgate control module supplies voltage for the endgate latch relay coil control circuit to the endgate latch relay. This output is used to energize the endgate latch relay when an endgate swing latch or drop latch request has been made. If the endgate module detects an open or short to ground on the endgate latch relay coil control circuit when a swing latch or drop latch request is made, a DTC is set.

Conditions for Setting the DTC
    • The endgate module detects an open or short to ground on the endgate latch relay coil control circuit.
    • Condition must be present when a swing latch request or drop latch request is made.

Action Taken When the DTC Sets
    • Stores a current DTC B3745 in endgate module memory.
    • Stores a history DTC B3745 in endgate module memory.
    • The endgate module will ignore the swing latch or drop latch request.

Conditions for Clearing the DTC
    • The endgate module no longer detects a current DTC B3745 in endgate module memory.
    • The DTC is cleared using a scan tool.

Diagnostic Aids
    • The following conditions may cause an intermittent malfunction:
       - There is an intermittent open in a endgate latch relay coil control circuit.
       - The endgate latch relay coil is open internally.
    • If the DTC does not reset after the code is cleared, then the problem may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

The number below refers to the step number on the diagnostic table.

  1. Tests the endgate latch relay coil control circuit.

Step

Action

Yes

No

Schematic Reference: Body Rear End Schematics

Connector End View Reference: Body Rear End Connector End Views

1

Did you perform the Body Rear End Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Body Rear End

2

  1. Remove the endgate latch relay.
  2. Connect a test lamp between the endgate latch relay coil control circuit of the endgate latch relay connector and a good ground.
  3. Install a scan tool.
  4. Turn ON the ignition, with the engine OFF.
  5. With a scan tool, command the endgate module to swing endgate.

Does the test lamp illuminate?

Go to Step 4

Go to Step 3

3

Test the endgate latch relay coil control circuit for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 8

Go to Step 5

4

Inspect for poor connections at the harness connector of the endgate latch relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 8

Go to Step 5

5

Inspect for poor connections at the harness connector of the endgate module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 8

Go to Step 7

6

Replace the endgate latch relay. Refer to Endgate Wiring Harness Replacement .

Did you complete the replacement?

Go to Step 8

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7
  1. Perform the endgate window learn procedure. Refer to Endgate Window Learn Cycle
  2. Replace the endgate module. Refer to Rear Body Control Module Replacement - Endgate .

Did you complete the replacement?

Go to Step 8

--

8
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK