| Table 1: | Electric Cooling Fan Functional Check |
| Table 2: | Electric Cooling Fan Table #1 |
| Table 3: | Electric Cooling Fan Table #2 |
| Table 4: | Electric Cooling Fan Table #3 |
Circuit Description:
The cooling fans are controlled by the PCM based on various inputs. Ignition voltage is supplied to all three cooling fan relay coils. The PCM controls cooling fan relay # 1 by providing the ground path. The PCM controls cooling fan relays # 2 and # 3 together by providing a ground path. The left and right cooling fans are connected in series. This will enable both fans on low speed when the fan #1 relay is energized. When all three fan relays are energized, both fans will operate at high speed. The high speed is possible because the fan relays are wired in a parallel circuit. When the PCM detects that certain DTCs are set, the PCM will enable the cooling fans.
The PCM will enable the engine cooling fans when certain Diagnostic Trouble Codes are set. The PCM will also enable the cooling fans after the ignition is turned off. When engine coolant temperature exceeds 140°C (284°F) and the ignition is turned off, the cooling fans will be enabled on low speed.
Diagnostic Aids
Cooling Fan #1 Relay Underhood Electrical Center Terminal Identification | |||
|---|---|---|---|
Front of Vehicle | |||
Driver Side of Vehicle | Control | B+ | Passenger Side of Vehicle |
Load | B+ | ||
Cooling Fan #2 Relay Underhood Electrical Center Terminal Identification | |||
|---|---|---|---|
Front of Vehicle | |||
Driver Side of Vehicle | Control | B+ | Passenger Side of Vehicle |
Load | Ignition | ||
If the owner complained of an overheating problem, determine if the complaint was due to an actual boil over, or the warning indicator light illuminated, or the engine coolant temperature gauge indicated overheating. The gauge accuracy can also be checked by comparing the Engine Coolant Temperature (ECT) sensor reading using a scan tool and comparing its reading with the gauge reading. If the engine is actually overheating and the gauge indicated overheating, but the cooling fan is not coming ON, the Engine Coolant Temperature (ECT) sensor has probably shifted out of calibration and should be replaced.
If the engine is overheating and the cooling fans are ON, the cooling system should be checked, refer to Engine Cooling.
The PCM will command low speed fans ON at 108°C (226°F) and OFF at 103°C (217°F) and, high speed fans ON at 113°C (235°F) and OFF at 108°C (219°F).
Test Description
The numbers below refer to numbers on the diagnostic table.
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The PCM will enable the engine cooling fans when certain Diagnostic Trouble Codes are set. Go to applicable DTC Table first before proceeding with this table.
-
Allow engine coolant temperature to cool below 100°C (212°F) before proceeding with diagnosis diagnoses.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to Powertrain OBD System Check | |
Are any DTCs set? | -- | Go to applicable DTC Table | ||
Are the cooling fans OFF? | 100°C (212°F) | Go to Cooling Fan table #1 | ||
4 | Command cooling fan relay #1 ON using a scan tool. Are both cooling fans ON? | -- | Go to Cooling Fan table #2 | |
5 | Command cooling fan relays #1, #2, and #3 ON using a scan tool. Do both cooling fans switch to high speed? | -- | Go to Cooling Fan table #3 | |
6 |
Are the cooling fans ON? | -- | ||
7 | Turn the A/C ON. Are the cooling fans ON? | -- | System OK | |
8 | Does the scan tool display A/C request as YES? | -- | Refer to Air Conditioning (A/C) Request Circuit Check for further diagnosis of the A/C system. | |
9 | Does the scan tool display A/C request as YES? | -- | Refer to DTC P0530 Air Conditioning (A/C) Refrigerant Pressure Sensor Circuit for further diagnosis of the A/C Refrigerant Pressure Sensor | Refer to Air Conditioning (A/C) Request Circuit Check for further diagnosis of the A/C system. |
10 |
Important: Program the replacement PCM. Refer to Powertrain Control Module/Throttle Actuator Control Module Replacement . Replace the PCM. Is the action complete? | -- | System OK | -- |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Cooling Fan Functional Check? | -- | Go to Cooling Fan Functional Check | |
2 | Disconnect fan relay #1 Are both fans OFF? | -- | ||
3 | Disconnect fan relay #3 Are both fans OFF? | -- | ||
4 | Probe cooling fan relay #3 harness connector terminal 86 using a test lamp J 35616-200 connected to B+. Does the test lamp illuminate? | -- | ||
5 |
Is the test lamp still illuminated? | -- | ||
6 | Probe cooling fan relay #1 harness connector terminal 86 using the test lamp J 35616-200 connected to B+. Does the test lamp illuminate? | -- | ||
7 |
Is the test lamp still illuminated? | -- | ||
8 | Repair circuit 409 and/or circuit 504 for a short to B+. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
9 | Replace the cooling fan relay. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
10 | Repair circuit 473 or 335 for a short to ground. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
11 |
Important:: Program the replacement PCM. Refer to Powertrain Control Module/Throttle Actuator Control Module Replacement . Replace the PCM. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Cooling Fan Functional Check? | -- | Go to Cooling Fan Functional Check | |
2 | Did either fan turn ON when cooling fan relay #1 was commanded ON? | -- | ||
3 | Command cooling fan relay #1 ON using a scan tool. Did the other fan turn OFF? | -- | ||
4 | Disconnect fan relay #2. Did the fan turn OFF? | -- | ||
5 |
Refer to Diagnostic Aids for terminal identification. Does the test lamp illuminate? | -- | ||
6 | Probe both Battery feed circuits at the underhood electrical center with a test lamp J 35616-200 connected to ground. Refer to Diagnostic Aids for terminal identification. Does test lamp illuminate for both circuits? | -- | ||
7 |
Important: Leave the jumper in place for remainder of this table. Connect a fused jumper wire between one battery feed circuit and the load circuit at the underhood electrical center. Do both fans turn ON? | -- | ||
8 |
Does the test lamp illuminate? | -- | ||
9 | Connect a second fused jumper wire between fan harness connector terminals. Is the right fan ON? | -- | ||
10 |
Is the test lamp ON? | -- | ||
11 | Using the second jumper wire, jumper fan relay #3 harness connector terminals 30 and 87A together. Does the fan comes ON? | -- | ||
12 |
Is the left fan ON? | -- | ||
13 |
Is the test lamp ON? | -- | ||
14 | Inspect the PCM connections. Repair faulty connections as necessary. Did you find a problem and correct it? | -- | Go to Cooling Fan Functional Check | |
15 | Repair circuit 335 for an open or shorted to B+. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
16 | Inspect the fan motor connections and repair as necessary. Was a problem and corrected? | -- | Go to Cooling Fan Functional Check | |
17 | Replace the fan motor. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
18 | Repair the open in circuit 250. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
19 | Replace the fan which was not operating. Is the action complete? | -- | Go to Cooling Fan Functional Check | --
|
20 | Replace fan relay #2. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
21 | Repair circuit 532 for a short to ground. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
22 | Repair the open or the grounded circuit for the circuit that did not light. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
23 | Replace fan relay #1. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
24 | Repair the open in circuit 409. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
25 | Repair the open in circuit 532. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
26 | Replace fan relay #3. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
27 |
Important: Program the replacement PCM. Refer to Powertrain Control Module/Throttle Actuator Control Module Replacement . Replace the PCM. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Cooling Fan Functional Check? | -- | Go to Cooling Fan Functional Check | |
2 |
Did both fans operate with no change? | -- | ||
3 | Did the left fan stop operating? | -- | ||
4 |
Did the test lamp illuminate? | -- | ||
5 | Probe the Ignition feed circuit for fan relay #2 at the underhood electrical center with a test lamp J 35616-200 connected to ground. Refer to Diagnostic Aids for terminal identification. Does the test lamp illuminate? | -- | ||
6 | Probe the Battery feed circuit for fan relay #2 at the underhood electrical center with a test lamp J 35616-200 connected to ground. Refer to Diagnostic Aids for terminal identification. Does the test lamp illuminate? | -- | ||
7 | Jumper the Battery feed circuit to the Load circuit for fan relay #2 at the underhood electrical center. Refer to Diagnostic Aids for terminal identification. Is the right fan ON? | -- | ||
8 |
Refer to Diagnostic Aids for terminal identification. Do the fans switch from low to high speed? | -- | ||
9 |
Did the test lamp illuminate? | -- | ||
10 | Probe fan relay #3 harness connector terminals 87 with a test lamp J 35616-200 connected to B+. Does the test lamp illuminate? | -- | ||
11 | Probe fan relay #3 harness connector terminals 85 with a test lamp J 35616-200 connected to ground. Does the test lamp illuminate? | -- | ||
12 | Repair circuit 473 for an open between fan relay #2 and the splice. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
13 | Repair the open ignition feed circuit to terminal 85 of the fan relay #2. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
14 | Repair the open battery feed circuit to terminal 30 of the fan relay. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
15 | Replace the fan relay #2. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
16 | Repair the open in circuit 504 between fan relay #2 and the splice. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
17 | Repair circuit 473 for an open or for a short to B+. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
18 | Repair the open in circuit 473 between fan relay #3 and the splice. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
19 | Repair the open in circuit 250. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
20 | Replace the fan relay #3. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
21 | Repair the open in ignition feed circuit to terminal 85 of the fan relay #3. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
22 |
Did you find a problem and correct it? | -- | Go to Cooling Fan Functional Check | |
23 |
Important:: Program the replacement PCM. Refer to Powertrain Control Module/Throttle Actuator Control Module Replacement . Replace the PCM. Is the action complete? | -- | Go to Cooling Fan Functional Check | -- |
