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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1078 (HVAC Systems - Automatic) >> Diagnostic Information and Procedures >> DTC B3933: Air Conditioning (A/C) Evaporator Temperature Sensor Circuit >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

  1. 3:  Tests for the proper operation of the circuit in the high voltage range.
  2. 4:  Tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to voltage.
DTC B3933

Step Action Value(s) Yes No
Schematic Reference:  HVAC Schematics  
Connector End View Reference:  HVAC Connector End Views  
1 Did you perform the HVAC Diagnostic System Check? - Go to Step 2  Go to Diagnostic System Check - HVAC Systems - Automatic 
2
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the Evaporator Temp parameter in the Heating, Ventilation and Air Conditioning data list.
Does the scan tool indicate that the Evaporator Temp parameter is within the specified range?		 -50°C (-58°F)-143°C (290°F) Go to Diagnostic Aids Go to Step 3 
3 
  1. Turn OFF the ignition.
  2. Disconnect the evaporator temperature sensor
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the Evaporator Temp parameter.
Does the scan tool indicate that the Evaporator Temp sensor parameter is equal to the specified value?		 -43°C (-45°F) Go to Step 5  Go to Step 4 
4 
  1. Turn OFF the ignition.
  2. Connect a 3-amp fused jumper wire between the signal circuit of the evaporator temperature sensor and the low reference circuit of the evaporator temperature sensor.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the Evaporator Temp parameter.
Does the scan tool indicate that the Evaporator Temp parameter is equal to the specified value?		 144°C (291°F) Go to Step 8  Go to Step 6 
5 Test the signal circuit of the evaporator temperature sensor for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 12  Go to Step 9 
6 Test the signal circuit of the evaporator temperature sensor for a short to voltage, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 12  Go to Step 7 
7 Test the low reference circuit of the evaporator temperature sensor for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 12  Go to Step 9 
8 Inspect for poor connections at the harness connector of the evaporator temperature sensor. 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 
9 Inspect for poor connections at the harness connector of the HVAC 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 
10 Replace the evaporator temperature sensor. Refer to Evaporator Temperature Sensor Replacement in Heating, Ventilation and Air Conditioning.
Did you complete the replacement?		 - Go to Step 12  -
11 Replace the HVAC control module. Refer to HVAC Control Module Replacement .
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
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