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Test Description

WARNING: This page is about a different car, the 2004 Pontiac Grand Prix. However, it is still accessible from the selected car via links, so may be relevant.

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

  1. 2:  Listen for an audible click when the fan 1 relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
  2. 3:  Listen for an audible click when the fan 2 and fan 3 relays operate. Command both the ON and OFF states. Repeat the commands as necessary.
  3. 4:  Tests for voltage at the coil side of the fan 1 relay. The FAN 1 fuse supplies battery positive voltage to the coil side of the fan 1 relay.
DTC P0480 or P0481

Step Action Yes No
Schematic Reference: Engine Cooling Schematics 
Connector End View Reference:  Cooling System Connector End Views  
1 Did you perform the Engine Cooling Diagnostic System Check? Go to Step 2  Go to Diagnostic System Check - Engine Cooling 
2 
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, command the Fans Low Speed ON and OFF.
Does the fan 1 relay turn ON and OFF with each command?		 Go to Step 3  Go to Step 4 
3  With a scan tool, command the Fans High Speed ON and OFF.
Do the fan 2 and the fan 3 relays turn ON and OFF with each command?		 Go to Diagnostic Aids Go to Step 6 
4 
  1. Turn OFF the ignition.
  2. Disconnect the fan 1 relay.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the battery positive voltage circuit of the fan 1 relay with a test lamp that is connected to a good ground.
Does the test lamp illuminate?		 Go to Step 5  Go to Step 16 
5
  1. Connect a test lamp between the control circuit of the fan 1 relay and the battery positive voltage circuit of the fan 1 relay.
  2. With a scan tool, command the Fans Low Speed ON and OFF.
Does the test lamp turn ON and OFF with each command?		 Go to Step 12  Go to Step 9 
6
  1. Turn OFF the ignition.
  2. Disconnect the fan 3 relay.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the battery positive voltage circuit of the fan 3 relay with a test lamp that is connected to a good ground.
Does the test lamp illuminate?		 Go to Step 7  Go to Step 16 
7
  1. Connect a test lamp between the control circuit of the fan 3 relay and the battery positive voltage circuit of the fan 3 relay.
  2. With a scan tool, command the Fans High Speed ON and OFF.
Does the test lamp turn ON and OFF with each command?		 Go to Step 14  Go to Step 8 
8
  1. Turn Off the ignition.
  2. Disconnect the fan 2 relay.
  3. Turn ON the ignition with the engine OFF.
  4. Connect a test lamp between the control circuit of the fan 2 relay and the battery positive voltage circuit of the fan 2 relay.
  5. With a scan tool, command the Fans High Speed ON and OFF.
Does the test lamp turn ON and OFF with each command?		 Go to Step 13  Go to Step 9 
9 Does the test lamp remain illuminated with each command? Go to Step 11  Go to Step 10 
10 Test the control circuit of the appropriate relay for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 21  Go to Step 15 
11 Test the control circuit of the appropriate relay for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 21  Go to Step 15 
12 Inspect for poor connections at the fan 1 relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 21  Go to Step 17 
13 Inspect for poor connections at the fan 2 relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 21  Go to Step 18 
14 Inspect for poor connections at the fan 3 relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 21  Go to Step 19 
15 Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 21  Go to Step 20 
16 Repair the battery positive voltage circuit. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 Go to Step 21  -
17 Replace the fan 1 relay.
Did you complete the replacement?		 Go to Step 21  -
18 Replace the fan 2 relay.
Did you complete the replacement?		 Go to Step 21  -
19 Replace the fan 3 relay.
Did you complete the replacement?		 Go to Step 21  -
20
IMPORTANT: Perform the programming procedure for the PCM.
Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement in Engine Controls - 3.8L.Did you complete the replacement?		 Go to Step 21  -
21
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC reset?		 Go to Step 2  System OK
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