Cooling Fan Circuit Diagnosis 2.0L DOHC European Emissions
Circuit Description
Caution: Refer to Electric Coolant Fan Caution in the Preface section.
The engine cooling fan circuit operates the main cooling fan and the auxiliary cooling fan. The cooling fans are controlled by the engine control module (ECM) based on inputs 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 connector terminal K28. This energizes the low speed cooling fan relay and operates the main cooling fan at low speed. The ECM controls the high speed cooling fan operation by internally grounding the ECM connector terminal K12. 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 condition, 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 fuses EF3 or EF10 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 fans are 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 96°C (205°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 94°C (201°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 1 859 kPa (269 psi) then return to low speed when the high side A/C pressure is 1 449 kPa (210 psi). |
| • | The cooling fan circuit can be inspected quickly by disconnecting the ECM connector and grounding the connector terminal K28. This should create low speed cooling fan operation with the ignition ON. By grounding the ECM connector terminals K12 and turn the ignition ON, high speed cooling fan operation should be achieved. |
Step | Action | Values | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
1 | Perform the Diagnostic System Check-Engine Controls. Was the check performed? | -- | Go to Step 2 | Go to Diagnostic System Check - Engine Controls in Engine Controls - 1.6L or Diagnostic System Check - Engine Controls in Engine Controls - 2.0L | ||||
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 |
Do the cooling fans run at low speed? | -- | Go to Step 7 | Go to Step 6 | ||||
6 |
Did you complete the repair? | -- | System OK | -- | ||||
7 |
Do the cooling fans run at high speed? | -- | System OK | -- | ||||
8 |
Did the test light illuminate? | -- | Go to Step 9 | Go to Step 12 | ||||
9 | Connect a test light between terminal 1 of the main cooling fan connector and battery positive. Did the test light illuminate? | -- | Go to Step 11 | Go to Step 10 | ||||
10 | Repair the open circuit between terminal 1 of the main cooling fan connector and ground. Did you complete the repair? | -- | System OK | -- | ||||
11 | Inspect for damaged terminals in the main cooling fan connector and repair it or replace the main cooling fan. Did you complete the repair? | -- | System OK | -- | ||||
12 |
Is the test light ON for both cases? | -- | Go to Step 14 | Go to Step 13 | ||||
13 | Repair the power supply circuit.
Did you complete the repair? | -- | 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. Refer to Engine Control Module Replacement . Did you complete the replacement? | -- | System OK | -- | ||||
16 |
Does the resistance meausure the specified value? | 0 ohms | Go to Step 18 | Go to Step 17 | ||||
17 | Repair the open circuit. Did you complete the repair? | -- | System OK | -- | ||||
18 | Replace the low speed cooling fan relay. Did you complete the repair? | -- | System OK | -- | ||||
19 |
Did the test light illuminate? | -- | Go to Step 20 | Go to Step 24 | ||||
20 | Connect a test light between terminal 1 of the auxiliary cooling fan connector and battery positive. Did the test light illuminate? | -- | Go to Step 21 | Go to Step 23 | ||||
21 | Replace the auxiliary cooling fan. Did you complete the replacement? | -- | System OK | Go to Step 22 | ||||
22 | Repair an open circuit between the following terminals:
Did you complete the repair? | -- | System OK | Go to Step 11 | ||||
23 | Repair an open circuit between terminal 1 of the auxiliary cooling fan connector and ground. Did you complete the repair? | -- | System OK | -- | ||||
24 |
Is the test light ON for both cases? | -- | Go to Step 26 | Go to Step 25 | ||||
25 | Repair the open power supply circuit:
Did you complete the repair? | -- | System OK | Go to Step 26 | ||||
26 |
Do the cooling fans run at high speed? | -- | Go to Step 15 | Go to Step 27 | ||||
27 |
Does the resistance measure the specified value? | 0 ohms | Go to Step 29 | Go to Step 28 | ||||
28 | Repair the open circuit between the specific circuit wiring. Did you complete the repair? | -- | System OK | -- | ||||
29 | Replace the high speed cooling fan relay. Did you complete the replacement? | -- | System OK | Go to Step 15 |
Cooling Fan Circuit Diagnosis 2.0L DOHC Non-Europe or NA Emissions
Circuit Description
Caution: Refer to Electric Coolant Fan Caution in the Preface section.
The engine cooling fan circuit operates the main cooling fan and the auxiliary cooling fan. The cooling fans are controlled by the engine control module (ECM) based on inputs 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 connector terminal A10. This energizes the low speed cooling fan relay and operates the main cooling fan at low speed. The ECM controls the high speed cooling fan operation by internally grounding the ECM connector terminal A14. 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 condition, 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 fuses EF3 or EF10 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 fans are 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 96°C (205°F). The ECM will turn the cooling fans OFF when the coolant temperature is 93°C (199°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). |
| • | 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 1 938 kPa (281 psi) then return to low speed when the high side A/C pressure is 1 510 kPa (219 psi). |
| • | The cooling fan circuit can be inspected quickly by disconnecting the ECM connector and grounding the connector terminal A10. This should create low speed cooling fan operation with the ignition ON. By grounding the ECM connector terminals A14 and turn the ignition ON, high speed cooling fan operation should be achieved. |
Step | Action | Values | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Diagnostic System Check-Engine Controls performed? | -- | Go to Step 2 | Go to Diagnostic System Check - Engine Controls in Engine Controls - 2.0L | ||||||
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 |
Do the cooling fans run at low speed? | -- | Go to Step 7 | Go to Step 6 | ||||||
6 |
Did you complete the repair? | -- | System OK | -- | ||||||
7 |
Do the cooling fans run at high speed? | -- | System OK | -- | ||||||
8 |
Did the test light illuminate? | -- | Go to Step 9 | Go to Step 12 | ||||||
9 | Connect a test light between terminal 1 of the main cooling fan connector and battery positive. Did the test light illuminate? | -- | Go to Step 11 | Go to Step 10 | ||||||
10 | Repair the open circuit between terminal 1 of the main cooling fan connector and ground. Did you complete the repair? | -- | System OK | -- | ||||||
11 | Inspect for damaged terminals in the main cooling fan connector and repair it or replace the main cooling fan. Did you complete the repair? | -- | System OK | -- | ||||||
12 |
Does the test light illuminate for both cases? | -- | Go to Step 14 | Go to Step 13 | ||||||
13 | Repair the power supply circuit.
Did you complete the repair? | -- | 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. Refer to Engine Control Module Replacement in Engine Controls-2.0L. Did you complete the replacement? | -- | System OK | -- | ||||||
16 |
Does the resistance meausure the specified value? | 0 ohms | Go to Step 18 | Go to Step 17 | ||||||
17 | Repair the open circuit. Did you complete the repair? | -- | System OK | -- | ||||||
18 | Replace the low speed cooling fan relay. Refer to Relay Replacement in Wiring Systems. Did you complete the repair? | -- | System OK | -- | ||||||
19 |
Did the test light illuminate? | -- | Go to Step 20 | Go to Step 24 | ||||||
20 | Connect a test light between terminal 1 of the auxiliary cooling fan connector and battery positive. Did the test light illuminate? | -- | Go to Step 21 | Go to Step 23 | ||||||
21 | Replace the auxiliary cooling fan. Refer to Engine Cooling Fan Replacement . Did you complete the replacement? | -- | System OK | Go to Step 22 | ||||||
22 | Repair an open circuit between the following terminals:
Did you complete the repair? | -- | System OK | Go to Step 11 | ||||||
23 | Repair an open circuit between terminal 1 of the auxiliary cooling fan connector and ground. Did you complete the repair? | -- | System OK | -- | ||||||
24 |
Does the test light illuminate for both cases? | -- | Go to Step 26 | Go to Step 25 | ||||||
25 | Repair the open power supply circuit:
Did you complete the repair? | -- | System OK | Go to Step 26 | ||||||
26 |
Do the cooling fans run at high speed? | -- | Go to Step 15 | Go to Step 27 | ||||||
27 |
Does the resistance measure the specified value? | 0 ohms | Go to Step 29 | Go to Step 28 | ||||||
28 | Repair the open circuit between the specific circuit wiring. Did you complete the repair? | -- | System OK | -- | ||||||
29 | Replace the high speed cooling fan relay. Did you complete the replacement? | -- | System OK | Go to Step 15 |
Cooling Fan Circuit Diagnosis 1.6L
Circuit Description
The engine cooling fan circuit operates the main cooling fan and the auxiliary cooling fan. The cooling fans are controlled by the engine control module (ECM) based on inputs 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 connector terminal 10. This energizes the low speed cooling fan relay and operates the main cooling fan and the auxiliary cooling fan at low speed as the cooling fans are connected in a series circuit. The ECM controls the high speed cooling fan operation by internally grounding the ECM connector terminal 10 and the ECM connector terminal 9 at the same time. This energizes the low speed cooling fan relay, the high speed cooling fan relay, and the series/parallel 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 condition, 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 fuses Ef6 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 fans are 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 101°C (214°F). The ECM will change the cooling fans from high speed to low speed when the coolant temperature is 98°C (208°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 1 882 kPa (273 psi) then return to low speed when the high side A/C pressure is 1 448 kPa (210 psi). When the A/C system is ON, the ECM will change the cooling fans from low to high speed when the coolant temperature reaches 117°C (244°F) then return to low speed when the coolant temperature reaches 114°C (237°F). |
| • | The cooling fan circuit can be inspected quickly by disconnecting the ECM connector 2 and grounding the connector terminal 10. This should create low speed cooling fan operation with the ignition ON. By grounding the ECM connector terminals 10 and 9 and turning the ignition ON, high speed cooling fan operation should be achieved. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step, along with step 5, inspects the ability of the ECM to operate the cooling fans.
-
This step, along with step 9, inspects the ability of the ECM to operate the cooling fans in response to A/C pressure readings.
-
After confirming battery voltage and the ECM supplying a ground to the coil side of the cooling fan relay low, by jumpering connector terminals 30 and 87 it will be determined if the relay is at fault or a wiring condition is present.
-
This step inspects 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 condition is in the ground side of the cooling fan circuit.
-
By directly grounding the ECM connector terminals 10 and 9, the main and auxiliary cooling fans should run at high speed.
Step | Action | Yes | No |
|---|---|---|---|
1 | Perform the Diagnostic System Check-Engine Controls. Is the check completed? | Go to Step 2 | Go to Diagnostic System Check - Engine Controls in Engine Controls - 1.6L. |
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 |
Do the cooling fans run at low speed? | Go to Step 5 | Go to Step 10 | |
5 |
Do the cooling fans run at high speed? | Go to Step 6 | Go to Step 33 |
6 |
Does the A/C compressor clutch engage? | Go to Step 8 | Go to Step 7 |
7 |
Does the A/C compressor clutch engage? | Go to Step 8 | -- |
Do the cooling fans run at low speed? | Go to Step 9 | Go to Step 31 | |
9 |
Do the cooling fans run at high speed? | Go to Step 10 | -- |
10 |
Is the test light ON? | Go to Step 11 | Go to Step 12 |
11 |
Is the test light ON? | Go to Step 28 | Go to Step 17 |
12 |
Is the test light ON? | Go to Step 13 | Go to Step 24 |
13 |
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 connector terminal 10. Is the condition found? | Go to Step 25 | Go to Step 15 |
15 |
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 |
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 condition 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 condition found? | Go to Step 22 | Go to Step 20 |
20 | Inspect the wire between the cooling fan control relay connector terminal 87A and the auxiliary cooling fan connector terminal 2 for an open. Is the condition 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 condition 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 Ef6. Is the repair complete? | System OK | -- |
24 | Repair the open between the cooling fan relay low connector terminal 86 and the ignition switch. Is the repair complete? | System OK | -- |
25 | 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 | -- |
26 | Replace the cooling fan relay low. Refer to Relay Replacement in Wiring Systems. Is the replacement complete? | System OK | -- |
27 | Replace the cooling fan control relay. Refer to Relay Replacement in Wiring Systems. Is the replacement complete? | System OK | -- |
28 | Replace the main cooling fan. Refer to Engine Cooling Fan Replacement . Is the replacement complete? | System OK | -- |
29 | Replace the auxiliary cooling fan. Refer to Engine Cooling Fan Replacement . Is the replacement complete? | System OK | -- |
30 | Replace the ECM. Refer to Engine Control Module Replacement in Engine Controls 1.6L. Is the replacement complete? | System OK | -- |
31 |
Is the test light ON? | Go to Step 32 | Go to Step 12 |
32 |
Is the test light ON? | Go to Step 28 | Go to Step 17 |
33 |
Is the test light ON? | Go to Step 34 | Go to Step 44 |
34 |
Is the test light ON? | Go to Step 35 | Go to Step 45 |
35 |
Is the test light ON? | Go to Step 36 | Go to Step 46 |
36 |
Is the test light ON? | Go to Step 37 | Go to Step 47 |
37 |
Do the cooling fans run at high speed? | Go to Step 30 | Go to Step 38 |
38 |
Is the condition found? | Go to Step 22 | Go to Step 39 |
39 |
Is the test light ON? | Go to Step 40 | Go to Step 48 |
40 |
Is the test light ON? | Go to Step 41 | Go to Step 49 |
41 |
Do the cooling fans run at high speed? | Go to Step 43 | Go to Step 42 |
42 |
Do the cooling fans run at high speed? | Go to Step 27 | -- |
43 | Replace the cooling fan relay high. Refer to Relay Replacement in Wiring Systems. Is the replacement complete? | System OK | -- |
44 | Repair the open wire between the cooling fan relay high connector terminal 86 and the ignition switch. Is the repair complete? | System OK | -- |
45 | Repair the open wire between the cooling fan relay high connector terminal 30 and the battery. Is the repair complete? | System OK | -- |
46 | Repair the open wire between the cooling fan control relay connector terminal 85 and the ignition switch. Is the repair complete? | System OK | -- |
47 | Repair the open wire between the cooling fan control relay connector terminal 87 and ground. Is the repair complete? | System OK | -- |
48 | Repair the open wire between the cooling fan relay high 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 control relay connector terminal 85 and the ECM connector terminal 9. Is the repair complete? | System OK | -- |
