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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 (Dual 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. 8:  This step, along with step 9, checks for the ability of the ECM to operate the cooling fans in response to A/C pressure readings.
  3. 16:  After confirming battery voltage and the ECM supplying a ground to the coil side of the cooling fan relay A, by jumpering connector terminals 30 and 87, it will be determined if the relay is at fault or a wiring problem is present.
  4. 31:  This step checks for the presence of battery voltage to the main cooling fan when the A/C is ON. If battery voltage is present and the cooling fans are not operating, the problem is in the ground side of the cooling fan circuit.
  5. 37:  By directly grounding the ECM low relay and high relay control circuits, the main and auxiliary cooling fans should run at high speed.
Cooling Fan Circuit Diagnosis (Dual Fan)

Step Action Yes No
1 Did you perform the Diagnostic Starting Point - Engine Cooling?
Is the procedure completed?		 Go to Step 2  Go to Diagnostic Starting Point - Engine Cooling 
2
  1. Inspect the I/P engine block fuse EF3.
  2. Replace the fuse as needed.
Is the fuse OK?		 Go to Step 3  Go to Diagnostic Aids
3
  1. Inspect the I/P fuse block fuse F18.
  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. Turn the A/C switch OFF.
  3. Connect a scan tool to the data link connector (DLC).
  4. The cooling fans should run at low speed when the coolant temperature reaches 97°C (207°F).
Do the cooling fans run at low speed?		 Go to Step 5  Go to Step 10 
5
  1. Turn the ignition OFF.
  2. Turn the A/C switch OFF.
  3. Connect a scan tool to the DLC.
  4. Start the engine.
  5. The cooling fans should run at high speed when the coolant temperature reaches 101°C (214°F).
Do the cooling fans run at high speed?		 Go to Step 6  Go to Step 33 
6
  1. Turn the ignition OFF.
  2. Start the engine.
  3. Turn the A/C switch ON.
Does the A/C compressor clutch engage?		 Go to Step 8  Go to Step 7 
7
  1. Diagnose the A/C compressor clutch circuit.
  2. Repair the A/C compressor clutch circuit as needed.
  3. Start the engine.
  4. Turn the A/C switch ON.
Does the A/C compressor clutch engage?		 Go to Step 8  -
8  Do the cooling fans run at low speed? Go to Step 9  Go to Step 31 
9
  1. Turn the ignition OFF.
  2. Connect the A/C pressure gages.
  3. Start the engine.
  4. Turn the A/C switch ON.
  5. The cooling fans should run at high speed when the high side A/C pressure reaches 1 882 kPa (273 psi).
Do the cooling fans run at high speed?		 Go to Step 10  Go to DTC P0532 or P0533
10
  1. Turn the ignition OFF.
  2. Connect a scan tool to the DLC.
  3. The coolant temperature should be above 97°C (207°C).
  4. Disconnect the main cooling fan connector.
  5. Turn the ignition ON.
  6. Connect a test light between the main cooling fan connector terminal 2 and ground.
Is the test light ON?		 Go to Step 11  Go to Step 12 
11
  1. Turn the ignition OFF.
  2. Connect a scan tool to the DLC.
  3. The coolant temperature should be above 97°C (207°C).
  4. Disconnect the main cooling fan connector.
  5. Connect a test light between the main cooling fan connector terminal 1 and B+.
Is the test light ON?		 Go to Step 28  Go to Step 17 
12
  1. Turn the ignition OFF.
  2. Disconnect the cooling fan relay LOW.
  3. Connect a test light between the cooling fan relay LOW connector terminal 86 and ground.
  4. Turn the ignition ON.
Is the test light ON?		 Go to Step 13  Go to Step 24 
13
  1. Turn the ignition OFF.
  2. Connect the cooling fan relay LOW.
  3. Disconnect engine control module (ECM) white connector.
  4. Connect a fused jumper between the ECM low cooling fan relay control circuit and ground.
  5. Turn the ignition ON.
Do the cooling fans run at low speed?		 Go to Step 30  Go to Step 14 
14 Inspect for an open wire between the low speed cooling fan relay connector terminal 86 and the ECM low cooling fan relay control circuit.
Is the problem found?		 Go to Step 25  Go to Step 15 
15
  1. Turn the ignition OFF.
  2. Disconnect the cooling fan relay LOW.
  3. Connect a test light between the cooling fan relay LOW connector terminal 30 and ground.
Is the test light ON?		 Go to Step 16  Go to Step 23 
16  Connect a fused jumper between the cooling fan relay LOW connector terminals 30 and 87.
Do the cooling fans run at low speed?		 Go to Step 26  Go to Step 17 
17
  1. Disconnect the series/parallel fan series/parallel relay.
  2. Connect a fused jumper between the cooling fan relay LOW connector terminals 30 and 87.
  3. Connect a fused jumper between the cooling fan series/parallel relay connector terminals 30 and 87.
Do the cooling fans run at low speed?		 Go to Step 27  Go to Step 18 
18 Inspect the wire between the cooling fan relay LOW connector terminal 87 to the main cooling fan connector terminal 2 for an open.
Is the problem found?		 Go to Step 22  Go to Step 19 
19 Inspect the wire between the main cooling fan connector terminal 1 and the cooling fan control relay connector terminal 30 for an open.
Is the problem found?		 Go to Step 22  Go to Step 20 
20 Inspect the wire between the cooling fan series/parallel relay connector terminal 87A and the auxiliary cooling fan connector terminal 2 for an open.
Is the problem found?		 Go to Step 22  Go to Step 21 
21 Inspect for an open wire between the auxiliary cooling fan connector terminal 1 and ground.
Is the problem found?		 Go to Step 22  Go to Step 29 
22 Repair the open wire as needed.
Is the repair complete?		 System OK -
23 Repair the open between the cooling fan relay LOW connector terminal 30 and the fuse EF3.
Is the repair complete?		 System OK -
24 Repair the open between the cooling fan relay LOW connector terminal 85 and the ignition switch.
Is the repair complete?		 System OK -
25 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 -
26 Replace the cooling fan relay LOW.
Is the repair complete?		 System OK -
27 Replace the cooling fan series/parallel relay.
Is the repair complete?		 System OK -
28 Replace the main cooling fan.
Is the repair complete?		 System OK -
29 Replace the auxiliary cooling fan.
Is the repair complete?		 System OK -
30 Replace the ECM. Refer to Engine Control Module (ECM) Replacement in Engine Controls 1.6L.
Is the repair complete?		 System OK -
31 
  1. Turn the ignition OFF.
  2. Disconnect the main cooling fan connector.
  3. Connect a test light between the main cooling fan connector terminal 2 and ground.
  4. Turn the A/C switch ON.
  5. Start the engine.
Is the test light ON?		 Go to Step 32  Go to Step 12 
32
  1. Turn the ignition OFF.
  2. Connect a test light between the main cooling fan connector terminal 1 and battery positive.
  3. Turn the A/C switch ON.
  4. Start the engine.
Is the test light ON?		 Go to Step 28  Go to Step 17 
33
  1. Turn the ignition OFF.
  2. Disconnect the cooling fan relay HI.
  3. Connect a test light between the cooling fan relay HI connector terminal 85 and ground.
  4. Turn the ignition ON.
Is the test light ON?		 Go to Step 34  Go to Step 44 
34
  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 35  Go to Step 45 
35
  1. Disconnect the cooling fan series/parallel relay.
  2. Connect a test light between the cooling fan series/parallel relay connector terminal 85 and ground.
  3. Turn the ignition ON.
Is the test light ON?		 Go to Step 36  Go to Step 46 
36
  1. Turn the ignition OFF.
  2. Connect a test light between the cooling fan series/parallel relay connector terminal 87 and battery positive.
Is the test light ON?		 Go to Step 37  Go to Step 47 
37 
  1. Connect the main cooling fan connector.
  2. Connect the cooling fan relay HI.
  3. Connect the cooling fan series/parallel relay.
  4. Disconnect the ECM connector.
  5. Connect a fused jumper between the ECM low cooling fan relay control circuit and ground.
  6. Connect a fused jumper between the ECM high cooling fan relay control circuit and ground.
  7. Turn the ignition ON.
Do the cooling fans run at high speed?		 Go to Step 30  Go to Step 38 
38
  1. Turn the ignition OFF.
  2. Inspect for an open wire between the cooling fan relay HI connector terminal 86 and the ECM high cooling fan relay control circuit and ground.
Is the problem found?		 Go to Step 22  Go to Step 39 
39
  1. Disconnect the cooling fan relay HI.
  2. Connect a test light between the cooling fan relay HI connector terminal 87 and battery positive.
Is the test light ON?		 Go to Step 40  Go to Step 48 
40
  1. Disconnect the ECM connector.
  2. Connect a fused jumper between the ECM high cooling fan relay control circuit and ground.
  3. Disconnect the cooling fan relay HI.
  4. Connect a test light between the cooling fan control relay connector terminal 86 and battery positive.
Is the test light ON?		 Go to Step 41  Go to Step 49 
41
  1. Connect the cooling fan control relay.
  2. Connect a fused jumper between the ECM high cooling fan relay control circuit and ground.
  3. Disconnect the cooling fan relay HI.
  4. Connect a fused jumper between the cooling fan relay HI connector terminals 30 and 87.
  5. Disconnect the low speed cooling fan relay.
  6. Connect a fused jumper between the low speed cooling fan relay connector terminals 30 and 87.
  7. Turn the ignition ON.
Do the cooling fans run at high speed?		 Go to Step 43  Go to Step 42 
42
  1. Turn the ignition OFF.
  2. Connect a fused jumper between the ECM high cooling fan relay control circuit and ground.
  3. Disconnect the cooling fan series/parallel relay.
  4. Connect a fused jumper between the cooling fan series/parallel relay connector terminals 30 and 87.
  5. Connect a fused jumper between the low speed cooling fan relay connector terminals 30 and 87.
  6. Turn the ignition ON.
Do the cooling fans run at high speed?		 Go to Step 27  -
43 Replace the cooling fan relay HI.
Is the repair complete?		 System OK -
44 Repair the open wire between the cooling fan relay HI connector terminal 85 and the ignition switch.
Is the repair complete?		 System OK -
45 Repair the open wire between the cooling fan relay HI connector terminal 30 and the battery.
Is the repair complete?		 System OK -
46 Repair the open wire between the cooling fan series/parallel relay connector terminal 85 and the ignition switch.
Is the repair complete?		 System OK -
47 Repair the open wire between the cooling fan series/parallel relay connector terminal 87 and ground.
Is the repair complete?		 System OK -
48 Repair the open wire between the cooling fan relay HI connector terminal 87 and the auxiliary cooling fan connector terminal 2.
Is the repair complete?		 System OK -
49 Repair the open wire between the cooling fan series/parallel relay connector terminal 85 and the ECM connector terminal K12.
Is the repair complete?		 System OK -
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