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Home >> Chevrolet >> 2005 >> Aveo Base, 4D Hatchback >> Repair and Diagnosis >> Engine Mechanical >> Cooling System (Mechanical) >> Engine Cooling System >> Diagnostic Information and Procedures >> Cooling Fan Circuit Diagnosis (Single Fan) >> Test Description

Test Description

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

  1. 4:  This step, along with step 5, checks for the ability of the ECM to operate the cooling fans.
  2. 22:  By directly grounding the ECM low cooling fan relay and high cooling fan relay control circuits, the cooling fan should run at high speed.
Cooling Fan Circuit Diagnosis (Single Fan)

Step Action Yes No
1 Did you perform the Diagnostic Starting Point - Engine Cooling? Go to Step 2  Go to Diagnostic Starting Point - Engine Cooling 
2
  1. Inspect the I/P fuse block fuse F18 for the 1.4L/1.5L application.
  2. Replace the fuse as needed.
Is the fuse OK?		 Go to Step 3  Go to Diagnostic Aids
3
  1. Inspect the engine fuse block fuse EF3.
  2. Replace the fuse as needed.
Is the fuse OK?		 Go to Step 4  Go to Diagnostic Aids
4 
  1. Turn the ignition OFF.
  2. Connect the scan tool to the data link connector (DLC).
  3. Start the engine.
  4. The cooling fan should run at low speed when the coolant temperature reaches 93°C (199°F).
Does the cooling fan run at low speed?		 Go to Step 5  Go to Step 6 
5
  1. Turn the ignition OFF.
  2. Connect a scan tool to the DLC.
  3. Start the engine.
  4. The cooling fan should run at high speed when the coolant temperature reaches 97°C (207°F).
Does the cooling fan run at high speed?		 System OK Go to Step 22 
6
  1. Turn the ignition OFF.
  2. Disconnect the engine control module (ECM) connector.
  3. Connect a fused jumper between the ECM low cooling fan relay control circuit and ground.
  4. Turn the ignition ON.
Does the cooling fan run at low speed?		 Go to Step 21  Go to Step 7 
7
  1. Turn the ignition OFF.
  2. Connect a fused jumper between the ECM low cooling fan relay control circuit and ground.
  3. Disconnect the cooling fan connector.
  4. Connect a test light between the cooling fan connector terminal 2 and ground.
  5. Turn the ignition ON.
Is the test light ON?		 Go to Step 8  Go to Step 9 
8
  1. Turn the ignition OFF.
  2. Connect a test light between the cooling fan connector terminal 1 and battery positive.
Is the test light ON?		 Go to Step 18  Go to Step 17 
9
  1. Turn the ignition OFF.
  2. Remove the jumper from the ECM low cooling fan control circuit.
  3. Using a test light, connect to ground, probe the low speed relay connector terminal 86.
  4. Turn the ignition ON.
Is the test light ON?		 Go to Step 10  Go to Step 13 
10
  1. Turn the ignition OFF.
  2. Connect a test light between the cooling fan relay LOW connector terminal 30 and ground.
Is the test light ON?		 Go to Step 11  Go to Step 14 
11 Connect a test light between the cooling fan relay LOW connector terminal 87 and battery positive.
Is the test light ON?		 Go to Step 12  Go to Step 16 
12
  1. Connect a fused jumper between the ECM low cooling fan relay control circuit and ground.
  2. Connect a test light between the cooling fan relay LOW connector terminal 85 and battery positive.
Is the test light ON?		 Go to Step 19  Go to Step 15 
13 Repair the open wire between the cooling fan relay LOW connector terminal 85 and the ignition voltage supply.
Is the repair complete?		 System OK -
14 Repair the open wire between the cooling fan relay LOW connector terminal 30 and the fuse EF3.
Is the repair complete?		 System OK -
15 Repair the open wire between the cooling fan relay LOW connector terminal 86 and the ECM low cooling fan relay control circuit.
Is the repair complete?		 System OK -
16 Inspect for an open wire between the cooling fan relay LOW connector terminal 87 and the cooling fan connector terminal 2.
Is the problem found?		 Go to Step 20  Go to Step 17 
17 Inspect for an open wire between the cooling fan connector terminal 1 and ground.
Is the problem found?		 Go to Step 20  Go to Step 18 
18 Replace the cooling fan. Refer to Cooling Fan Replacement - Electric 
Is the repair complete?		 System OK -
19 Replace the cooling fan relay LOW.
Is the repair complete?		 System OK -
20 Repair the wire as needed.
Is the repair complete?		 System OK -
21 Replace the ECM.
Is the repair complete		 System OK -
22 
  1. Turn the ignition OFF.
  2. Disconnect the ECM connector.
  3. Connect a fused jumper between the ECM low cooling fan relay control circuit and ground.
  4. Connect a fused jumper between the ECM high cooling fan relay control circuit and ground.
  5. Turn the ignition ON.
Does the cooling fan run at high speed?		 Go to Step 21  Go to Step 23 
23
  1. Turn the ignition OFF.
  2. Disconnect the cooling fan relay HI.
  3. Connect a test light between the cooling fan relay high connector terminal 85 and ground.
  4. Turn the ignition ON.
Is the test light ON?		 Go to Step 24  Go to Step 28 
24
  1. Turn the ignition OFF.
  2. Connect a test light between the cooling fan relay HI connector terminal 30 and ground.
Is the test light ON?		 Go to Step 25  Go to Step 29 
25 Connect a test light between the cooling fan relay HI connector terminal 87 and ground.
Is the test light ON?		 Go to Step 26  Go to Step 30 
26
  1. Connect a fused jumper between the ECM high cooling fan control circuit and ground.
  2. Connect a test light between the cooling fan relay HI connector terminal 86 and battery positive.
Is the test light ON?		 Go to Step 27  Go to Step 31 
27 Replace the cooling fan relay HI.
Is the repair complete?		 System OK -
28 Repair the open wire between the cooling fan relay HI connector terminal 85 and the ignition switch voltage supply.
Is the repair complete?		 System OK -
29 Repair the open wire between the cooling fan relay HI connector terminal 30 and the fuse EF3.
Is the repair complete?		 System OK -
30 Repair the open wire between the cooling fan relay HI connector terminal 87 and the cooling fan connector terminal 2.
Is the repair complete?		 System OK -
31 Repair the open wire between the cooling fan relay HI connector terminal 86 and the ECM relay control circuit.
Is the repair complete?		 System OK -
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