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NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [MZR-CD (RF Turbo)]

BME010300103288

17 | COOLING SYSTEM CONCERNS-OVERHEATING
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DESCRIPTION | • Engine runs at higher than normal temperature/overheats.
POSSIBLE CAUSE | • Improper coolant level • Blown fuses • Coolant leakage • Excessive A/C system pressure • Improper water/anti-freeze mixture
• Fans reverse rotation
• Poor radiator condition
• Thermostat malfunction
• Radiator hoses damage
• Condenser fan is inoperative.
• Improper or damaged radiator cap
• Cooling fan is inoperative.
• Coolant overflow system malfunction
• Improper tension of drive belt
• Drive belt damage
• Fan control module malfunction

Diagnostic Procedure

STEP | INSPECTION | RESULTS | ACTION
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1 | Inspect the following: • Engine coolant level • Coolant leakage (around heater unit in passenger compartment, coolant hoses and/or radiator, and around coolant heater unit.) • Water and anti-freeze mixture • Radiator condition
• Collapsed or restricted radiator hoses
• Radiator pressure cap
• Drive belt tension
• Drive belt
• Fan rotational direction
Are all items normal?
Yes
Go to the next step.
No | Service if necessary. Repeat Step 1.
2 | Perform self-test function using the WDS or equivalent. Turn the engine switch to the ON position. Retrieve any DTC. Is DTC displayed? | Yes | DTC is displayed: Go to the applicable DTC inspection. (See DTC TABLE [MZR-CD (RF Turbo)].) Communication error message is displayed: Inspect for the following:
• Open circuit between PCM control relay and PCM terminal 53 or 79
• Open circuit PCM control relay and PCM terminal 69
• PCM control relay stuck open
• Open or poor GND circuit (PCM terminal 65, 85, 103 or 104)
• Poor connection vehicle body GND
No | No DTC is displayed: Go to the next step.
3 |

  Note

  • The following test should be performed on the vehicles with the A/C system. Go to the next step for the vehicles without the A/C system
Start the engine and run it at idle speed.
Turn the A/C switch off.
Does the A/C compressor disengaged?

Yes
Go to the next step.
No | Go to symptom troubleshooting "NO.24 A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY". (See NO.24 A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZR-CD (RF Turbo)].)
4 | Start the engine and run it at idle speed. Turn the A/C switch on if equipped. Do the compressor fan and/or the cooling fan operate? | Yes | Go to the next step.
No | Cooling fan motor does not operate: • Inspect for the following:

  - Cooling fan motor malfunction
  - Cooling fan motor GND open
  - Open circuit between cooling fan motor and fan control module

Condenser fan motor does not operate:
• Inspect for the following:

  - Condenser fan motor malfunction
  - Condenser fan motor GND open
  - Open circuit between condenser fan motor and fan control module

Both cooling fan and condenser fan do not operate:
• Inspect for the following:

  - Fan control module malfunction
  - Fan control module GND open
  - Open circuit between fan control module and cooling fan relay

5 | Is the drive belt normal? | Yes | Go to the next step.
No | Replace the drive belt.
6 | Perform the EGR system inspection. Is the EGR system normal? | Yes | Go to the next step.
No | Repair or replace the malfunctioning part according to the EGR system operation results.
7 | Inspect the EGR water cooler for the following: • Coolant passage clogging/restriction • Exhaust gas clogging/restriction Is the EGR water cooler normal? | Yes | Go to the next step.
No | Service if necessary.
8 | Perform the coolant heater system inspection. (See THERMOSTAT INSPECTION.) Is the coolant heater system normal? | Yes | Go to the next step.
No | Repair or replace the malfunctioning part according to the coolant heater system operation results.
9 | Cool down the engine. Remove the thermostat and inspect operation. Is the thermostat normal? | Yes | The thermostat is normal. Inspect the cylinder block for leakage or blockage.
No | Replace the thermostat.
10 | Verify test results. • If normal, return to diagnostic index to service any additional symptoms. • If malfunction remains, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZR-CD (RF Turbo)].)