DTC P0481:00 [MZR 1.6]

id0102h3704700

DTC P0481:00

Cooling fan relay No.2 and No.3 control circuit problem
DETECTION CONDITION
•  The PCM monitors the cooling fan relay No.2 and No.3 control signal voltage and current. If the following conditions are met, the PCM determines that there is the cooling fan relay No.2 and No.3 control circuit problem.
―  The PCM turns the cooling fan relay No.2 and No.3 off, but the voltage of the cooling fan relay No.2 and No.3 control signal remains low.
―  The PCM turns the cooling fan relay No.2 and No.3 on, but the current of the cooling fan relay No.2 and No.3 control signal remains high.
Diagnostic support note
•  This is continuous monitor (other).
•  The check engine light does not illuminate.
•  FREEZE FRAME DATA (Mode 2)/Snapshot data is not available.
•  DTC is stored in the PCM memory.
POSSIBLE CAUSE
•  Cooling fan relay No.2 and/or No.3 malfunction
•  Short to ground or open circuit in cooling fan relay No.2 and/or No.3 power supply circuit
―  Short to ground in wiring harness between the following terminals:
•  Main relay terminal D—Cooling fan relay No.2 terminal A
•  Main relay terminal D—Cooling fan relay No.3 terminal A
―  ENGINE3 15 A fuse malfunction
―  Open circuit in wiring harness between the following terminals:
•  Main relay terminal D—Cooling fan relay No.2 terminal A
•  Main relay terminal D—Cooling fan relay No.3 terminal A
•  PCM connector or terminals malfunction
•  Short to ground in wiring harness between the following terminals:
―  Cooling fan relay No.2 terminal E—PCM terminal 1Z
―  Cooling fan relay No.3 terminal E—PCM terminal 1Z
•  Short to power supply in wiring harness between the following terminals:
―  Cooling fan relay No.2 terminal E—PCM terminal 1Z
―  Cooling fan relay No.3 terminal E—PCM terminal 1Z
•  Open circuit in wiring harness between the following terminals:
―  Cooling fan relay No.2 terminal E—PCM terminal 1Z
―  Cooling fan relay No.3 terminal E—PCM terminal 1Z
•  PCM malfunction

Diagnostic Procedure

STEP

INSPECTION

ACTION
1
VERIFY RELATED SERVICE INFORMATION AVAILABILITY
•  Verify related Service Information availability.
•  Is any related Service Information available?
Yes
Perform repair or diagnosis according to the available Service Information.
•  If the vehicle is not repaired, go to the next step.
No
Go to the next step.
2
INSPECT COOLING FAN RELAY NO.2 AND NO.3
•  Switch the ignition off.
•  Remove the cooling fan relay No.2 and No.3.
•  Inspect the cooling fan relay No.2 and No.3.
•  Is there any malfunction?
Yes
Replace the cooling fan relay No.2 and/or No.3, then go to Step 8.
No
Go to the next step.
3
INSPECT COOLING FAN RELAY NO.2 AND NO.3 POWER SUPPLY CIRCUIT FOR SHORT TO GROUND OR OPEN CIRCUIT
•  Cooling fan relay No.2 and No.3 are removed.
•  Switch the ignition ON (engine off).
•  Measure the voltage at the following terminals (wiring harness-side):
―  Cooling fan relay No.2 terminal A
―  Cooling fan relay No.3 terminal A
•  Is the voltage B+?
Yes
Go to the next step.
No
Inspect the ENGINE3 15 A fuse.
•  If the fuse is blown:
―  Refer to the wiring diagram and verify whether or not there is a common connector between the following terminals:
•  Main relay terminal D—Cooling fan relay No.2 terminal A
•  Main relay terminal D—Cooling fan relay No.3 terminal A
If there is a common connector:
•  Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground.
•  Repair or replace the malfunctioning part.
If there is no common connector:
•  Repair or replace the wiring harness which has a short to ground.
•  Replace the fuse.
•  If the fuse is damaged:
―  Replace the fuse.
•  If the fuse is normal:
―  Refer to the wiring diagram and verify whether or not there is a common connector between the following terminals:
•  Main relay terminal D—Cooling fan relay No.2 terminal A
•  Main relay terminal D—Cooling fan relay No.3 terminal A
If there is a common connector:
•  Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit.
•  Repair or replace the malfunctioning part.
If there is no common connector:
•  Repair or replace the wiring harness which has an open circuit.
Go to Step 8.
4
INSPECT PCM CONNECTOR CONDITION
•  Switch the ignition off.
•  Disconnect the PCM connector.
•  Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
•  Is there any malfunction?
Yes
Repair or replace the connector and/or terminals, then go to Step 8.
No
Go to the next step.
5
INSPECT COOLING FAN RELAY NO.2 AND NO.3 SIGNAL CIRCUIT FOR SHORT TO GROUND
•  Cooling fan relay No.2 and No.3 are removed.
•  Verify that the PCM connector is disconnected.
•  Inspect for continuity between the following terminals (wiring harness-side) and body ground:
―  Cooling fan relay No.2 terminal E
―  Cooling fan relay No.3 terminal E
•  Is there continuity?
Yes
Refer to the wiring diagram and verify whether or not there is a common connector between the following terminals:
•  Cooling fan relay No.2 terminal E—PCM terminal 1Z
•  Cooling fan relay No.3 terminal E—PCM terminal 1Z
If there is a common connector:
•  Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground.
•  Repair or replace the malfunctioning part.
If there is no common connector:
•  Repair or replace the wiring harness which has a short to ground.
Go to Step 8.
No
Go to the next step.
6
INSPECT COOLING FAN RELAY NO.2 AND NO.3 SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY
•  Cooling fan relay No.2 and No.3 are removed.
•  Verify that the PCM connector is disconnected.
•  Switch the ignition ON (engine off).
Note
•  Another DTC may be stored by the PCM detecting an open circuit.
•  Measure the voltage at the following terminals (wiring harness-side):
―  Cooling fan relay No.2 terminal E
―  Cooling fan relay No.3 terminal E
•  Is the voltage 0 V?
Yes
Go to the next step.
No
If there is no common connector:
Refer to the wiring diagram and verify whether or not there is a common connector between the following terminals:
•  Cooling fan relay No.2 terminal E—PCM terminal 1Z
•  Cooling fan relay No.3 terminal E—PCM terminal 1Z
If there is a common connector:
•  Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to power supply.
•  Repair or replace the malfunctioning part.
•  Repair or replace the wiring harness which has a short to power supply.
Go to Step 8.
7
INSPECT COOLING FAN RELAY NO.2 AND NO.3 SIGNAL CIRCUIT FOR OPEN CIRCUIT
•  Cooling fan relay No.2 and No.3 are removed.
•  Verify that the PCM connector is disconnected.
•  Switch the ignition off.
•  Inspect for continuity between the following terminals (wiring harness-side):
―  Cooling fan relay No.2 terminal E—PCM terminal 1Z
―  Cooling fan relay No.3 terminal E—PCM terminal 1Z
•  Is there continuity?
Yes
Go to the next step.
No
Refer to the wiring diagram and verify whether or not there is a common connector between the following terminals:
•  Cooling fan relay No.2 terminal E—PCM terminal 1Z
•  Cooling fan relay No.3 terminal E—PCM terminal 1Z
If there is a common connector:
•  Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit.
•  Repair or replace the malfunctioning part.
If there is no common connector:
•  Repair or replace the wiring harness which has an open circuit.
Go to the next step.
8
VERIFY DTC TROUBLESHOOTING COMPLETED
•  Always reconnect all disconnected connectors.
•  Clear the DTC from the PCM memory using the M-MDS.
•  Perform the KOEO or KOER self test.
•  Is the same DTC present?
Yes
Repeat the inspection from Step 1.
•  If the malfunction recurs, replace the PCM.
Go to the next step.
No
Go to the next step.
9
VERIFY AFTER REPAIR PROCEDURE
•  Perform the “AFTER REPAIR PROCEDURE”.
•  Are any DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [MZR 1.6].)
No
DTC troubleshooting completed.