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STEP
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INSPECTION
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ACTION
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1
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VERIFY FREEZE FRAME DATA HAS BEEN RECORDED
• Has FREEZE FRAME DATA been recorded?
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Yes
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Go to the next step.
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No
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Record the FREEZE FRAME DATA on the repair order, then go to next step.
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2
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VERIFY REPAIR INFORMATION AVAILABILITY
• Verify related service repair information availability.
• Is any related repair information available?
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Yes
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Perform repair or diagnosis according to the available repair information.
• If the vehicle is not repaired, go to next step.
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No
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Go to the next step.
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3
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INDETIFY TRIGGER DTC FOR FEEZE FRAME DATA
• Is DTC P0481 on FREEZE FRAME DATA?
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Yes
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Go to the next step.
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No
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Go to FREEZE FRAME DATA DTC inspection.
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4
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INSPECT HIGH SPEED FAN CONTROL (HFC) CIRCUIT FOR INTERMITTENT FAILURE
• Rerun KOEO, KOER self test and Continuous Memory DTCs.
• Is DTC P0481 present in Continuous Memory self test only?
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Yes
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Go to Step 10.
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No
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Go to the next step.
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5
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CHECK VPWR VOLTAGE TO MFC RELAY
• Disconnect high speed fan control relay No.1 and No.2.
• Turn the ignition switch to ON.
• Start the engine.
• Measure VPWR circuit voltages at high speed fan relay No.1 and No.2 harness connector terminal 85.
• Is voltage greater than 10.5 V?
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Yes
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Go to the next step.
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No
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Repair open circuit, then go to Step 12.
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6
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CHECK FOR HFC CIRCUIT CYCLING
• Turn the ignition switch to ON.
• Connect a non-powered test lamp between VPWR circuit and the HFC circuit at each high speed fan relay harness connector terminal 85 to 86.
• Access Output Test Mode HFC PID on the WDS or equivalent.
• While observing test lamp, command the HFC PID on and off.
• Does the test lamp turned on and off when the cooling fan output is commanded on and off?
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Yes
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Replace malfunctioning high speed cooling fan relay, then go to Step 12.
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No
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Go to the next step.
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7
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CHECK HFC CIRCUIT FOR SHORT TO POWER IN HARNESS
• Disconnect PCM.
• Turn the ignition switch to ON.
• Measure voltage between high speed cooling fan control relay No.1, No.2 terminal 86 at harness side connector and ground.
• Is voltage less than 1.0 V?
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Yes
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Go to the next step.
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No
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Repair short circuit, then go to Step 12.
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8
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CHECK HFC CIRCUIT FOR SHORT TO GROUND HARNESS
• Disconnect WDS or equivalent to DLC.
• Measure resistance between each high speed cooling fan control relay terminal 86 at harness side connector and ground.
• Is resistance greater than 10.0 ohms?
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Yes
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Go to the next step.
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No
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Repair short to ground circuit, then go to Step 12.
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9
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CHECK FOR OPEN HFC CIRCUIT
• Measure the resistance of the HFC circuit between the PCM terminal 46 and each high speed cooling fan control relay connector terminal 85 at harness side connector.
• Is resistance less than 5.0 ohms?
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Yes
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Replace PCM, then go to Step 12.
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No
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Repair open circuit, then go to Step 12.
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10
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CHECK HFC CORCUIT FOR OPEN OR SHORT TO POWER
• A/C and defroster off.
• Disconnect cooling fan connector (both applications with two fans).
• Connect a non-powered test lamp between (HIGH) FAN PWR circuit and ground circuit at the cooling fan harness connector (either one for applications with two fans).
• Turn the ignition switch to ON.
• Access Output Test Mode HFC PID on the WDS or equivalent.
• Command HFC PID to on.
• Observe test lamp for an indication of a fault while completing the following (the lamp will turn off when a fault is detected, indicating an open or short to power):
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- Shake wiggle and bend the HFC circuit between PCM and each high speed cooling fan control relay.
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- Shake wiggle and bend the VPWR circuit to the each high speed cooling fan control relay
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- Lightly tap on the each high speed cooling fan control relay to simulate road shock
• Is fault indicated?
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Yes
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Isolate fault and repair, repair or replace malfunctioning part.
Then go to Step 12.
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No
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Go to the next step.
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11
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CHECK HFC CIRCUIT FOR SHORT TO GND
• Turn the ignition switch to ON.
• Command HFC PID to off using Output Test Mode on the WDS or equivalent.
• Observe the test lamp for an indication of a fault while completing the following (the lamp will turn on when a fault is detected, indicating HFC circuit short to ground):
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- Shake wiggle and bend the HFC circuit between PCM and HFC relays.
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- Lightly tap on the HFC relays to simulate road shock
• Is fault indicated?
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Yes
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Isolate fault and repair, repair or replace malfunctioning part.
Then go to the next step.
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No
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Intermittent concern exists, go to Intermittent Troubleshooting Procedure.
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12
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VERIFY TROUBLESHOOTING OF DTC P0481 COMPLETED
• Make sure to reconnect all disconnected connectors.
• Clear the DTC from the PCM memory using the WDS or equivalent.
• Perform KOEO/KOER self test.
• Is the PENDING CODE same DTC present?
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Yes
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Replace PCM, then go to next step.
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No
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Go to the next step.
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13
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VERIFY AFTER SERVICE PROCEDURE
• Perform "AFTER SERVICE PROCEDURE".
• Is there any DTC present?
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Yes
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Go to applicable DTC inspection.
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No
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Troubleshooting completed.
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