DTC P0481:00 [MZR 1.5, MZR 1.6]

id0102f0704700

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 MIL does not illuminate.
•  FREEZE FRAME DATA (Mode 2)/Snapshot data is not available.
•  The DTC is stored in the PCM memory.
POSSIBLE CAUSE
•  Open circuit or short to ground in cooling fan relay No.2 and No.3 power supply circuit
―  Short to ground in wiring harness between the following terminals:
•  Ignition switch*1/Relay block*2—Cooling fan relay No.2 terminal E
•  Ignition switch*1/Relay block*2—Cooling fan relay No.3 terminal E
―  ENG 20 A fuse malfunction
―  Open circuit in wiring harness between the following terminals:
•  Ignition switch*1/Relay block*2—Cooling fan relay No.2 terminal E
•  Ignition switch*1/Relay block*2—Cooling fan relay No.3 terminal E
•  Open circuit or short to ground in cooling fan relay No.3 power supply circuit
―  Short to ground in wiring harness between battery positive terminal and cooling fan relay No.3 terminal C
―  FAN1 40 A fuse and/or FAN3 30 A fuse malfunction
―  Open circuit in wiring harness between battery positive terminal and cooling fan relay No.3 terminal C
•  Cooling fan relay No.2 and/or No.3 malfunction
•  Short to ground in wiring harness between the following terminals:
―  Cooling fan relay No.2 terminal A—PCM terminal 1AZ
―  Cooling fan relay No.3 terminal A—PCM terminal 1AZ
•  PCM connector or terminals malfunction
•  Short to power supply in wiring harness between the following terminals:
―  Cooling fan relay No.2 terminal A—PCM terminal 1AZ
―  Cooling fan relay No.3 terminal A—PCM terminal 1AZ
•  Open circuit in wiring harness between the following terminals:
―  Cooling fan relay No.2 terminal A—PCM terminal 1AZ
―  Cooling fan relay No.3 terminal A—PCM terminal 1AZ
•  PCM malfunction

*1  :Vehicles without advanced keyless entry and push button start system
*2  :Vehicles with advanced keyless entry and push button start system

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 POWER SUPPLY CIRCUIT FOR OPEN CIRCUIT OR SHORT TO GROUND
•  Switch the ignition to off.
•  Remove the cooling fan relay No.2 and No.3.
•  Switch the ignition to ON (engine off).
•  Measure the voltage 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 the voltage B+?
Yes
Go to the next step.
No
Inspect the ENG 20 A fuse.
•  If the fuse is melt:
―  Repair or replace the wiring harness for a possible short to ground.
―  Replace the fuse.
•  If the fuse is deterioration:
―  Replace the fuse.
•  If the fuse is normal:
―  Repair or replace the wiring harness for a possible open circuit.
Go to Step 9.
3
INSPECT COOLING FAN RELAY NO.3 POWER SUPPLY CIRCUIT FOR OPEN CIRCUIT OR SHORT TO GROUND
•  Cooling fan relay No.2 and No.3 are removed.
•  Measure the voltage between cooling fan relay No.3 terminal C (wiring harness-side) and body ground.
•  Is the voltage B+?
Yes
Go to the next step.
No
Inspect the FAN1 40 A fuse and FAN3 30 A fuse.
•  If the fuse is melt:
―  Repair or replace the wiring harness for a possible short to ground.
―  Replace the malfunctioning fuse.
•  If the fuse is deterioration:
―  Replace the malfunctioning fuse.
•  If the fuse is normal:
―  Repair or replace the wiring harness for a possible open circuit.
Go to Step 9.
4
INSPECT COOLING FAN RELAY NO.2 AND NO.3
•  Switch the ignition to off.
•  Inspect the cooling fan relay No.2 and No.3.
•  Is there any malfunction?
Yes
Replace the malfunctioning part according to the inspection results, then go to Step 9.
No
Go to the next step.
5
INSPECT COOLING FAN RELAY NO.2 AND NO.3 CONTROL CIRCUIT FOR SHORT TO GROUND
•  Cooling fan relay No.2 and No.3 are removed.
•  Inspect for continuity between the following terminals (wiring harness-side) and body ground:
―  Cooling fan relay No.2 terminal A
―  Cooling fan relay No.3 terminal A
•  Is there continuity?
Yes
If the short to ground circuit could be detected:
•  Repair or replace the wiring harness for a possible short to ground.
If the short to ground circuit could not be detected:
•  Replace the PCM (short to ground in PCM internal circuit).
Go to Step 9.
No
Go to the next step.
6
INSPECT PCM CONNECTOR AND TERMINALS
•  Disconnect the PCM connector.
•  Inspect for poor connection (such as damaged, pulled-out pins, and corrosion).
•  Is there any malfunction?
Yes
Repair or replace the connector or terminals, then go to Step 9.
No
Go to the next step.
7
INSPECT COOLING FAN RELAY NO.2 AND NO.3 CONTROL CIRCUIT FOR SHORT TO POWER SUPPLY
•  Cooling fan relay No.2 and No.3 are removed.
•  PCM connector is disconnected.
•  Switch the ignition to ON (engine off).
•  Measure the voltage between the following terminals (wiring harness-side) and body ground:
―  Cooling fan relay No.2 terminal A
―  Cooling fan relay No.3 terminal A
•  Is there any voltage?
Yes
Repair or replace the wiring harness for a possible short to power supply, then go to Step 9.
No
Go to the next step.
8
INSPECT COOLING FAN RELAY NO.2 AND NO.3 CONTROL CIRCUIT FOR OPEN CIRCUIT
•  Cooling fan relay No.2 and No.3 are removed.
•  PCM connector is disconnected.
•  Switch the ignition to off.
•  Inspect for continuity between the following terminals (wiring harness-side):
―  Cooling fan relay No.2 terminal A—PCM terminal 1AZ
―  Cooling fan relay No.3 terminal A—PCM terminal 1AZ
•  Is there continuity?
Yes
Go to the next step.
No
Repair or replace the wiring harness for a possible open circuit, then go to the next step.
9
VERIFY DTC TROUBLESHOOTING COMPLETED
•  Make sure to 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.
10
VERIFY AFTER REPAIR PROCEDURE
•  Perform the “AFTER REPAIR PROCEDURE”.
•  Are any DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [MZR 1.5, MZR 1.6].)
No
DTC troubleshooting completed.