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HOMESERVICE MANUALSGMC1999FORWARD CONTROL 5.7 R, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 830 (ENGINE COOLING)DIAGNOSTIC INFORMATION AND PROCEDURESDTC B0936TEST DESCRIPTION
1999 GMC Forward Control 5.7 R, Automatic

Test Description

1999 GMC Forward Control 5.7 R, AutomaticSECTION Test Description
WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

The number(s) below refer to the step number(s) on the diagnostic table.

  1. 2:  Verifies the normal status of the signal circuit to the body control module.
  2. 3:  Tests for voltage at the coolant level switch. The BACKUP fuse supplies power to the voltage side of the coolant level switch.
  3. 4:  Verifies that the body control module is providing ground to the coolant.
DTC B0936

Step Action Yes No
Connector End View Reference:  Cooling System Connector End Views  
1 Did you perform the Engine Cooling Diagnostic System Check? Go to Step 2  Go to Diagnostic System Check - Engine Cooling 
2 
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the low coolant level switch input.
Does the scan tool display normal state?		 Go to Diagnostic Aids Go to Step 3 
3 
  1. Turn OFF the ignition.
  2. Disconnect the coolant level switch.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the ignition voltage circuit of the coolant level switch with a test lamp that is connected to a good ground.
Does the test lamp illuminate?		 Go to Step 4  Go to Step 9 
4 
  1. Connect a test lamp between the coolant level switch signal of the coolant level switch and the ignition voltage circuit of the coolant level switch.
  2. With a scan tool, observe the low coolant switch input status.
Does the scan tool display normal state?		 Go to Step 7  Go to Step 5 
5 Test the switch signal of the coolant level switch for a short to voltage or an open. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 12  Go to Step 8 
6 Test the switch signal of the coolant level switch for a short to ground. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 12  Go to Step 8 
7 Inspect for poor connections at the coolant level switch. 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 12  Go to Step 10 
8 Inspect for poor connections at the harness connector of the body control 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 12  Go to Step 11 
9 Repair the ignition voltage circuit of the coolant level switch. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 Go to Step 12  -
10 Replace the coolant level switch. Refer to Surge Tank Replacement .
Did you complete the replacement?		 Go to Step 12  -
11
IMPORTANT: Perform the set up procedure for the body control module.
Replace the body control module. Refer to Body Control Module Replacement in Body Control System.Did you complete the replacement?		 Go to Step 12  -
12
  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
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.