Contents Wiring diagrams Section: Cooling System (Mechanical) All sections

Engine Cooling System: Overview Chevrolet Aveo I facelift

Test Description

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

  1. 6: A test lamp that remains illuminated indicates a short to ground on the control circuit. A test lamp that does not illuminate indicates an open or short to voltage on the control circuit.
  2. 8: This step tests the control circuit for high resistance.
StepActionValuesYesNo
Schematic Reference: Engine Cooling Schematics (Notchback) or Engine Cooling Schematics (Hatchback) Connector End View Reference: Cooling System Connector End Views (Notchback) or Cooling System Connector End Views (Hatchback)
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2Turn ON the ignition, with the engine OFF. With a scan tool, command the Fan Low Speed ON and OFF. Does the relay turn ON and OFF with each command?Go to Step 3Go to Step 4
3With a scan tool, command the Fan High Speed ON and OFF. Do the relay turn ON and OFF with each command?Go to Diagnostic AidsGo to Step 4
4Turn OFF the ignition. Disconnect the affected relay. Turn ON the ignition, with the engine OFF. Probe the ignition 1 voltage circuit of the affected relay coil with a test lamp connected to a good ground. Does the test lamp illuminate?Go to Step 5Go to Step 13
5Turn ON the ignition, with the engine OFF. Probe the control circuit of the affected relay with a test lamp connected to battery positive. With a scan tool, command the affected relay ON and OFF. Does the test lamp turn ON and OFF?Go to Step 7Go to Step 6
6Does the test lamp remain illuminated?Go to Step 9Go to Step 10
7Turn OFF the ignition. Disconnect the MAIN relay in the underhood fuse block. Measure the resistance of the ignition 1 voltage circuit of the affected relay coil from the MAIN relay terminal to the affected relay terminal. Is the resistance less than the specified value?3 ohmsGo to Step 8Go to Step 13
8Turn ON the ignition, with the engine OFF. IMPORTANT: Use a test lamp that measures between 25-30 ohms for this test. Probe the control circuit of the affected relay with a test lamp connected to battery positive voltage. With a scan tool, command the affected relay ON. Measure the voltage from the probe of the test lamp to a good ground with a DMM. Is the voltage less than the specified value?2.5 VGo to Step 11Go to Step 10
9Test the control circuit of the affected relay for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 16Go to Step 12
10Test the control circuit of the affected relay for one of the following conditions: An open A short to voltage High resistance Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 16Go to Step 12
11Test for shorted terminals and poor connections at the affected relay. Refer to Testing for Intermittent Conditions and Poor Connections . Did you find and correct the condition?Go to Step 16Go to Step 14
12Test for shorted terminals and poor connections at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections . Did you find and correct the condition?Go to Step 16Go to Step 15
13Repair the open, short to ground, or high resistance on the ignition 1 voltage circuit. Refer to Wiring Repairs . Did you complete the repair?Go to Step 16
14Replace the affected relay. Refer to Relay Replacement (Within an Electrical Center) . Did you complete the replacement?Go to Step 16
15Replace the ECM. Did you complete the replacement?Go to Step 16
16Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. Did the DTC fail this ignition?Go to Step 2Go to Step 17
17Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - VehicleSystem OK
IMPORTANT
Use a test lamp that measures between 25-30 ohms for this test.

Symptoms - Engine Cooling

IMPORTANTThe following steps must be completed before using the symptom tables.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-300843-S03018657462008101600000) before using the Symptom Tables in order to verify that all of the following are true: There are no DTCs set. The control module(s) can communicate via the serial data link.
  2. Review the system operation in order to familiarize yourself with the system functions. Refer to «Cooling System Description and Operation»(ref-300853-S25033250582008101600000) .

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.
StepActionYesNo
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2Inspect the I/P engine block fuse EF3. Replace the fuse as needed. Is the fuse OK?Go to Step 3Go to Diagnostic Aids
3Inspect the I/P fuse block fuse F18. Replace the fuse as needed. Is the fuse OK?Go to Step 4Go to Diagnostic Aids
4Turn the ignition OFF. Turn the A/C switch OFF. Connect a scan tool to the data link connector (DLC). 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 5Go to Step 10
5Turn the ignition OFF. Turn the A/C switch OFF. Connect a scan tool to the DLC. Start the engine. 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 6Go to Step 33
6Turn the ignition OFF. Start the engine. Turn the A/C switch ON. Does the A/C compressor clutch engage?Go to Step 8Go to Step 7
7Diagnose the A/C compressor clutch circuit. Repair the A/C compressor clutch circuit as needed. Start the engine. Turn the A/C switch ON. Does the A/C compressor clutch engage?Go to Step 8
8Do the cooling fans run at low speed?Go to Step 9Go to Step 31
9Turn the ignition OFF. Connect the A/C pressure gages. Start the engine. Turn the A/C switch ON. 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 10Go to DTC P0532 or P0533
10Turn the ignition OFF. Connect a scan tool to the DLC. The coolant temperature should be above 97°C (207°C). Disconnect the main cooling fan connector. Turn the ignition ON. Connect a test light between the main cooling fan connector terminal 2 and ground. Is the test light ON?Go to Step 11Go to Step 12
11Turn the ignition OFF. Connect a scan tool to the DLC. The coolant temperature should be above 97°C (207°C). Disconnect the main cooling fan connector. Connect a test light between the main cooling fan connector terminal 1 and B+. Is the test light ON?Go to Step 28Go to Step 17
12Turn the ignition OFF. Disconnect the cooling fan relay LOW. Connect a test light between the cooling fan relay LOW connector terminal 86 and ground. Turn the ignition ON. Is the test light ON?Go to Step 13Go to Step 24
13Turn the ignition OFF. Connect the cooling fan relay LOW. Disconnect engine control module (ECM) white connector. Connect a fused jumper between the ECM low cooling fan relay control circuit and ground. Turn the ignition ON. Do the cooling fans run at low speed?Go to Step 30Go to Step 14
14Inspect 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 25Go to Step 15
15Turn the ignition OFF. Disconnect the cooling fan relay LOW. Connect a test light between the cooling fan relay LOW connector terminal 30 and ground. Is the test light ON?Go to Step 16Go to Step 23
16Connect 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 26Go to Step 17
17Disconnect the series/parallel fan series/parallel relay. Connect a fused jumper between the cooling fan relay LOW connector terminals 30 and 87. 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 27Go to Step 18
18Inspect 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 22Go to Step 19
19Inspect 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 22Go to Step 20
20Inspect 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 22Go to Step 21
21Inspect for an open wire between the auxiliary cooling fan connector terminal 1 and ground. Is the problem found?Go to Step 22Go to Step 29
22Repair the open wire as needed. Is the repair complete?System OK
23Repair the open between the cooling fan relay LOW connector terminal 30 and the fuse EF3. Is the repair complete?System OK
24Repair the open between the cooling fan relay LOW connector terminal 85 and the ignition switch. Is the repair complete?System OK
25Repair 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
26Replace the cooling fan relay LOW. Is the repair complete?System OK
27Replace the cooling fan series/parallel relay. Is the repair complete?System OK
28Replace the main cooling fan. Is the repair complete?System OK
29Replace the auxiliary cooling fan. Is the repair complete?System OK
30Replace the ECM. Is the repair complete?System OK
31Turn the ignition OFF. Disconnect the main cooling fan connector. Connect a test light between the main cooling fan connector terminal 2 and ground. Turn the A/C switch ON. Start the engine. Is the test light ON?Go to Step 32Go to Step 12
32Turn the ignition OFF. Connect a test light between the main cooling fan connector terminal 1 and battery positive. Turn the A/C switch ON. Start the engine. Is the test light ON?Go to Step 28Go to Step 17
33Turn the ignition OFF. Disconnect the cooling fan relay HI. Connect a test light between the cooling fan relay HI connector terminal 85 and ground. Turn the ignition ON. Is the test light ON?Go to Step 34Go to Step 44
34Turn the ignition OFF. Connect a test light between the cooling fan relay HI connector terminal 30 and ground. Is the test light ON?Go to Step 35Go to Step 45
35Disconnect the cooling fan series/parallel relay. Connect a test light between the cooling fan series/parallel relay connector terminal 85 and ground. Turn the ignition ON. Is the test light ON?Go to Step 36Go to Step 46
36Turn the ignition OFF. 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 37Go to Step 47
37Connect the main cooling fan connector. Connect the cooling fan relay HI. Connect the cooling fan series/parallel relay. Disconnect the ECM connector. Connect a fused jumper between the ECM low cooling fan relay control circuit and ground. Connect a fused jumper between the ECM high cooling fan relay control circuit and ground. Turn the ignition ON. Do the cooling fans run at high speed?Go to Step 30Go to Step 38
38Turn the ignition OFF. 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 22Go to Step 39
39Disconnect the cooling fan relay HI. Connect a test light between the cooling fan relay HI connector terminal 87 and battery positive. Is the test light ON?Go to Step 40Go to Step 48
40Disconnect the ECM connector. Connect a fused jumper between the ECM high cooling fan relay control circuit and ground. Disconnect the cooling fan relay HI. Connect a test light between the cooling fan control relay connector terminal 86 and battery positive. Is the test light ON?Go to Step 41Go to Step 49
41Connect the cooling fan control relay. Connect a fused jumper between the ECM high cooling fan relay control circuit and ground. Disconnect the cooling fan relay HI. Connect a fused jumper between the cooling fan relay HI connector terminals 30 and 87. Disconnect the low speed cooling fan relay. Connect a fused jumper between the low speed cooling fan relay connector terminals 30 and 87. Turn the ignition ON. Do the cooling fans run at high speed?Go to Step 43Go to Step 42
42Turn the ignition OFF. Connect a fused jumper between the ECM high cooling fan relay control circuit and ground. Disconnect the cooling fan series/parallel relay. Connect a fused jumper between the cooling fan series/parallel relay connector terminals 30 and 87. Connect a fused jumper between the low speed cooling fan relay connector terminals 30 and 87. Turn the ignition ON. Do the cooling fans run at high speed?Go to Step 27
43Replace the cooling fan relay HI. Is the repair complete?System OK
44Repair the open wire between the cooling fan relay HI connector terminal 85 and the ignition switch. Is the repair complete?System OK
45Repair the open wire between the cooling fan relay HI connector terminal 30 and the battery. Is the repair complete?System OK
46Repair the open wire between the cooling fan series/parallel relay connector terminal 85 and the ignition switch. Is the repair complete?System OK
47Repair the open wire between the cooling fan series/parallel relay connector terminal 87 and ground. Is the repair complete?System OK
48Repair 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
49Repair 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

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.
StepActionYesNo
1Did you perform the Diagnostic System Check-Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2Inspect the I/P fuse block fuse F18 for the 1.4L/1.5L application, or underhood fuse EF2 for the 1.2L. Replace the fuse as needed. Is the fuse OK?Go to Step 3Go to Diagnostic Aids
3Inspect the engine fuse block fuse EF3. Replace the fuse as needed. Is the fuse OK?Go to Step 4Go to Diagnostic Aids
4Turn the ignition OFF. Connect the scan tool to the data link connector (DLC). Start the engine. 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 5Go to Step 6
5Turn the ignition OFF. Connect a scan tool to the DLC. Start the engine. 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 OKGo to Step 22
6Turn the ignition OFF. Disconnect the engine control module (ECM) connector. Connect a fused jumper between the ECM low cooling fan relay control circuit and ground. Turn the ignition ON. Does the cooling fan run at low speed?Go to Step 21Go to Step 7
7Turn the ignition OFF. Connect a fused jumper between the ECM low cooling fan relay control circuit and ground. Disconnect the cooling fan connector. Connect a test light between the cooling fan connector terminal 2 and ground. Turn the ignition ON. Is the test light ON?Go to Step 8Go to Step 9
8Turn the ignition OFF. Connect a test light between the cooling fan connector terminal 1 and battery positive. Is the test light ON?Go to Step 18Go to Step 17
9Turn the ignition OFF. Remove the jumper from the ECM low cooling fan control circuit. Using a test light, connect to ground, probe the low speed relay connector terminal 86. Turn the ignition ON. Is the test light ON?Go to Step 10Go to Step 13
10Turn the ignition OFF. Connect a test light between the cooling fan relay LOW connector terminal 30 and ground. Is the test light ON?Go to Step 11Go to Step 14
11Connect a test light between the cooling fan relay LOW connector terminal 87 and battery positive. Is the test light ON?Go to Step 12Go to Step 16
12Connect a fused jumper between the ECM low cooling fan relay control circuit and ground. Connect a test light between the cooling fan relay LOW connector terminal 85 and battery positive. Is the test light ON?Go to Step 19Go to Step 15
13Repair the open wire between the cooling fan relay LOW connector terminal 85 and the ignition voltage supply. Is the repair complete?System OK
14Repair the open wire between the cooling fan relay LOW connector terminal 30 and the fuse EF3. Is the repair complete?System OK
15Repair 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
16Inspect 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 20Go to Step 17
17Inspect for an open wire between the cooling fan connector terminal 1 and ground. Is the problem found?Go to Step 20Go to Step 18
18Replace the cooling fan. Refer to Engine Cooling Fan Replacement . Is the repair complete?System OK
19Replace the cooling fan relay LOW. Is the repair complete?System OK
20Repair the wire as needed. Is the repair complete?System OK
21Replace the ECM. Is the repair completeSystem OK
22Turn the ignition OFF. Disconnect the ECM connector. Connect a fused jumper between the ECM low cooling fan relay control circuit and ground. Connect a fused jumper between the ECM high cooling fan relay control circuit and ground. Turn the ignition ON. Does the cooling fan run at high speed?Go to Step 21Go to Step 23
23Turn the ignition OFF. Disconnect the cooling fan relay HI. Connect a test light between the cooling fan relay high connector terminal 85 and ground. Turn the ignition ON. Is the test light ON?Go to Step 24Go to Step 28
24Turn the ignition OFF. Connect a test light between the cooling fan relay HI connector terminal 30 and ground. Is the test light ON?Go to Step 25Go to Step 29
25Connect a test light between the cooling fan relay HI connector terminal 87 and ground. Is the test light ON?Go to Step 26Go to Step 30
26Connect a fused jumper between the ECM high cooling fan control circuit and ground. Connect a test light between the cooling fan relay HI connector terminal 86 and battery positive. Is the test light ON?Go to Step 27Go to Step 31
27Replace the cooling fan relay HI. Is the repair complete?System OK
28Repair the open wire between the cooling fan relay HI connector terminal 85 and the ignition switch voltage supply. Is the repair complete?System OK
29Repair the open wire between the cooling fan relay HI connector terminal 30 and the fuse EF3. Is the repair complete?System OK
30Repair 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
31Repair the open wire between the cooling fan relay HI connector terminal 86 and the ECM relay control circuit. Is the repair complete?System OK

Cooling System Description and Operation

The cooling system maintains the engine temperature at an efficient level during all engine operating conditions. When the engine is cold, the cooling system cools the engine slowly or not at all. This slow cooling of the engine allows the engine to warm up quickly.

The cooling system includes a radiator and recovery subsystem, cooling fans, a thermostat and housing, a coolant pump, and a coolant pump drive belt. The timing belt drives the coolant pump.

All components must function properly in order for the cooling system to operate. The coolant pump draws the coolant from the radiator. The coolant then circulates through water jackets in the engine block, the intake manifold, and the cylinder head. When the coolant reaches the operating temperature of the thermostat, the thermostat opens. The coolant then goes back to the radiator where it cools.

This system directs some coolant through the hoses to the heater core. This provides for heating and defrosting. The surge tank is connected to the radiator to recover the coolant displaced by expansion from the high temperatures. The surge tank maintains the correct coolant level.

The cooling system for this vehicle has no radiator cap or filler neck. The coolant is added to the cooling system through the surge tank.