Cooling Fan Circuit Diagnosis 0.8L
Circuit Description
Caution: Refer to Electric Coolant Fan Caution in the Preface section.
The engine cooling fan circuit operates the cooling fan. The cooling fan is controlled by the engine control module (ECM) based on input from the coolant temperature sensor (CTS) and the A/C ON/OFF. The ECM controls the low speed cooling fan operation by internally grounding the ECM connector terminal 39. This energizes the low speed cooling fan relay and operates the cooling fan at low speed. The low speed cooling fan operation is achieved by the cooling fan resistor causing a drop in the voltage supplied to the cooling fan. The ECM controls the high speed cooling fan operation by internally grounding the ECM connector terminal 5. This energizes the high speed cooling fan relay, bypassing the radiator fan resistor. This results in high speed cooling fan operation.
Diagnostic Aids
| • | If the owner complained of an overheating problem, it must be determined if the complaint was due to an actual boil over, or the engine coolant temperature gage indicated overheating. If the engine is overheating and the cooling fans are ON, the cooling system should be inspected. |
| • | If the engine fuse block fuse EF15 becomes open, blown, immediately after installation, inspect for a short to ground in the wiring of the appropriate circuit. If the fuse becomes open, blown when the cooling fans are to be turned ON by the engine control module (ECM), suspect a faulty cooling fan motor. |
| • | The ECM will turn the cooling fan ON at low speed when the coolant temperature is 93°C (199°F). The ECM will turn the cooling fans OFF when the coolant temperature is 90°C (194°F). |
| • | The ECM will turn the cooling fans ON at high speed when the coolant temperature is 100°C (212°F). The ECM will change the cooling fans from high speed to low speed when the coolant temperature is 97°C (207°F). |
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Diagnostic Starting Point-Engine Cooling? | -- | Go to Step 2 | |
2 |
Are the fuses OK? | -- | Go to Step 3 | Go to Diagnostic Aids |
3 |
Does the cooling fan run at low speed? | -- | Go to Step 4 | Go to Step 8 |
4 | The cooling fans should run at high speed when the coolant temperature reaches 100°C (212°F). Do the cooling fans run at high speed? | -- | Go to Step 5 | Go to Step 19 |
5 |
Does the cooling fan runs at low speed? | -- | Go to Step 7 | Go to Step 6 |
6 |
Is the repair complete? | -- | System OK | -- |
7 |
Do the cooling fans run at high speed? | -- | System OK | -- |
8 |
Is the test light ON? | -- | Go to Step 9 | Go to Step 12 |
9 | Connect a test light between terminal 2 of cooling fan connector and battery positive. Is the test light ON? | -- | Go to Step 11 | Go to Step 10 |
10 | Repair the open circuit between terminal 2 of cooling fan connector and ground. Is the repair complete? | -- | System OK | -- |
11 | Inspect for a damaged terminal in main cooling fan connector and repair it or replace the main cooling fan. Is the repair complete? | -- | System OK | -- |
12 |
Is the test light ON for both case? | -- | Go to Step 14 | Go to Step 13 |
13 | Repair power supply circuit fuse EF15 and terminal 30 of the low speed cooling fan relay. Is the repair complete? | -- | System OK | Go to Step 14 |
14 |
Does the cooling fan run at low speed? | -- | Go to Step 15 | Go to Step 16 |
15 | Replace the ECM. Is the repair complete? | -- | System OK | -- |
16 |
Is the resistance within the value specified? | 0 ohms | Go to Step 18 | Go to Step 17 |
17 | Repair the open circuit. Is the repair complete? | -- | System OK | -- |
18 | Replace the low speed cooling fan relay. Is the repair complete? | -- | System OK | -- |
19 | Replace the high speed cooling fan relay. Is the repair complete? | -- | System OK | -- |
Cooling Fan Circuit Diagnosis 1.0L - European Emissions
Circuit Description
Caution: An electric fan under the hood can start up even when the engine is not running and can injure you. Keep hands, clothing and tools away from any underhood electric fan.
The engine cooling fan circuit operates the cooling fan. The cooling fan is controlled by engine control module (ECM) based on input from the Engine Coolant Temperature (ECT)sensor. The ECM controls the low speed cooling fan operation by internally grounding the ECM connection terminal 10. This energizes the low speed cooling fan relay and operates the cooling fan at low speed. The low speed cooling fan operation is achieved by the cooling fan resistor causing a drop in the voltage supplied to the cooling fan. The ECM controls the high speed cooling fan operation by internally grounding the ECM connector terminal 9. This energizes the high speed cooling fan relay, bypassing the radiator fan resistor. This results in high speed cooling fan operation.
Diagnostic Aids
| • | If the owner complained of an overheating problem, it must be determined if the complaint was due to an actual boil over, or the engine coolant temperature gage indicated overheating and the cooling fans are on, the cooling system should be checked. |
| • | If the fuse EF19 or the engine fuse block fuse EF3 become open immediately after installation, inspect for a short to ground in the wiring of the appropriate circuit. If the fuses become open when the cooling fan is to be turned on by the ECM, suspect a faulty cooling fan motor. |
| • | The ECM will turn the cooling fans on at low speed when the coolant temperature is 93°C (199°F). The ECM will turn the cooling fans off when the coolant temperature is 90°C (194°F). |
| • | The ECM will turn the cooling fans on at high speed when the coolant temperature is 100°C (212°F). The ECM will change the cooling fans from high speed to low speed when the coolant temperature is 97°C (207°F). |
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the Diagnostic Starting Point-Engine Cooling? | Go to Step 2 | |
2 |
Is the fuse OK? | Go to Step 3 | Go to Diagnostic Aids |
3 |
Is the fuse OK? | Go to Step 4 | Go to Diagnostic Aids |
4 |
Does the cooling fan run at low speed? | Go to Step 5 | Go to Step 6 |
5 |
Does the cooling fan run at high speed? | System OK | Go to Step 22 |
6 |
Does the cooling fan run at low speed? | Go to Step 21 | Go to Step 7 |
7 |
Is the test light on? | Go to Step 8 | Go to Step 9 |
8 |
Is the test light on? | Go to Step 18 | Go to Step 17 |
9 |
Is the test light on? | Go to Step 10 | Go to Step 13 |
10 |
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 |
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 86 and the ignition switch. Is the repair complete? | System OK | -- |
14 | Repair the open wire between the cooling fan relay Low connector terminal 30 and the fuse EF15. Is the repair complete? | System OK | -- |
15 | Repair the open wire between the cooling fan relay Low connector terminal 85 and the ECM connector terminal 10. 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 Low. 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. 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 |
Does the cooling fan run at high speed? | Go to Step 21 | Go to Step 23 |
23 |
Is the test light on? | Go to Step 24 | Go to Step 28 |
24 |
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 battery positive. Is the test light on? | Go to Step 26 | Go to Step 30 |
26 |
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 86 and the ignition switch. Is the repair complete? | System OK | -- |
29 | Repair the open wire between the cooling fan relay Hi connector terminal 30 and the fuse EF15. 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 Hi. Is the repair complete | System OK | -- |
31 | Repair the open wire between the cooling fan relay Hi connector terminal 85 and the ECM connector terminal 9. Is the repair complete? | System OK | -- |
Cooling Fan Circuit Diagnosis 1.0L - Non European Emissions
Circuit Description
Caution: An electric fan under the hood can start up even when the engine is not running and can injure you. Keep hands, clothing and tools away from any underhood electric fan.
The engine cooling fan circuit operates only the main cooling fan. The cooling fan is controlled by engine control module (ECM) based on input from the Engine Coolant Temperature (ECT) sensor and the Air Conditioning Pressure (ACP) sensor. The ECM controls the low speed cooling fan operation by internally grounding the ECM connection terminal 10. This energizes the low speed cooling fan relay and operates the cooling fan at low speed. The low speed cooling fan operation is achieved by the cooling fan resistor causing a drop in the voltage supplied to the cooling fan. The ECM controls the high speed cooling fan operation by internally grounding the ECM connector terminal 9. This energizes the high speed cooling fan relay resulting in high speed fan operation as the cooling fans are now connected in a parallel circuit.
Diagnostic Aids
| • | If the owner complained of an overheating problem, it must be determined if the complaint was due to an actual boil over, or the engine coolant temperature gage indicated overheating, If the engine is overheating and the cooling fans are on, the cooling system should be checked. |
| • | If fuses EF19 or EF15 become open (blown) immediately after installation, inspect for a short to ground in the wiring of the appropriate circuit. If the fuses become open (blown) when the cooling fan is to be turned on by the ECM, suspect a faulty cooling fan motor. |
| • | The ECM will turn the cooling fans on at low speed when the coolant temperature is 97°C (207°F). The ECM will turn the cooling fans off when the coolant temperature is 94°C (201°F). |
| • | The ECM will turn the cooling fans on at high speed when the coolant temperature is 101C (214°F). The ECM will change the cooling fans from high speed to low speed when the coolant temperature is 97°C (207°F). |
| • | The ECM will turn the cooling fans on at low speed when the A/C system is on. The ECM will change the cooling fans from low speed to high speed when the high side A/C pressure is 1,860 kPa (270 psi) then return to low speed when the high side A/C pressure is 1,447 kPa (210 psi). |
| • | The cooling fan circuit can be checked quickly by disconnecting the ECM connector and grounding the connector terminal 9. This should create low speed cooling fan operation with the ignition ON. By grounding the ECM connector terminals 10 and turning the ignition ON, high speed cooling fan operation should be achieved. |
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the Diagnostic Starting Point-Engine Cooling? | Go to Step 2 | |
2 |
Is the fuse OK? | Go to Step 3 | Go to Diagnostic Aids |
3 |
Is the fuse OK? | Go to Step 4 | Go to Diagnostic Aids |
4 |
Does the cooling fan run at low speed? | Go to Step 5 | Go to Step 6 |
5 |
Does the cooling fan run at high speed? | System OK | Go to Step 22 |
6 |
Does the cooling fan run at low speed? | Go to Step 21 | Go to Step 7 |
7 |
Is the test light on? | Go to Step 8 | Go to Step 9 |
8 |
Is the test light on? | Go to Step 18 | Go to Step 17 |
9 |
Is the test light on? | Go to Step 10 | Go to Step 13 |
10 |
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 |
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 86 and the ignition switch. Is the repair complete? | System OK | -- |
14 | Repair the open wire between the cooling fan relay Low connector terminal 30 and the fuse EF15. Is the repair complete? | System OK | -- |
15 | Repair the open wire between the cooling fan relay Low connector terminal 85 and the ECM connector terminal 10. 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 Low. 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. 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 |
Does the cooling fan run at high speed? | Go to Step 21 | Go to Step 23 |
23 |
Is the test light on? | Go to Step 24 | Go to Step 28 |
24 |
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 battery positive. Is the test light on? | Go to Step 26 | Go to Step 30 |
26 |
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 86 and the ignition switch. Is the repair complete? | System OK | -- |
29 | Repair the open wire between the cooling fan relay Hi connector terminal 30 and the fuse EF15. 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 Hi. Is the repair complete | System OK | -- |
31 | Repair the open wire between the cooling fan relay Hi connector terminal 85 and the ECM connector terminal 9. Is the repair complete? | System OK | -- |
