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

BME010300000W52

17 | COOLING SYSTEM CONCERNS-OVERHEATING
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DESCRIPTION | • Engine runs at higher than normal temperature/overheats.
POSSIBLE CAUSE | • Main fan malfunction • Additional fan malfunction • Low drive belt tension • Drive belt damage • Improper coolant level
• Thermostat malfunction
• Radiator clogging
• Improper water/anti-freeze mixture
• Improper or damaged radiator cap
• Radiator hose damage
• Coolant leakage (engine internal, turbocharger, external)
• A/C system malfunction
• EGR system malfunction
• EGR water cooler malfunction
• Coolant heater system malfunction

Diagnostic Procedure

STEP | INSPECTION | RESULTS | ACTION
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1 | Inspect 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 okay?
Yes
Go to next step.
No | Service as necessary. Repeat Step 1.
2 | Perform self-test function using WDS or equivalent. Turn engine switch to ON. Retrieve any DTC. Is DTC displayed? | Yes | DTC is displayed: Go to appropriate DTC test. Communication error message is displayed: Inspect for 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 next step.
3 |

  Note

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

Yes
Go to next step.
No | Go to symptom troubleshooting "NO.24 A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY".
4 | Start engine and run it at idle speed. Turn A/C switch on if equipped. Do compressor fan and/or cooling fan operate? | Yes | Go to next step.
No | Additional fan does not operate: Inspect for following: • Additional fan relay is stuck open • Additional fan motor malfunction • Additional fan motor GND open
• Open circuit between additional fan motor and relay
• Open circuit between additional fan relay and PCM terminal 102
• Open battery power circuit of condenser fan relay

Main fan motor does not operate:

Inspect for following:
• Main fan relay is stuck open
• Main fan motor malfunction
• Main fan motor GND open
• Open circuit between main fan motor and relay
• Open circuit between main fan relay and PCM terminal 76
• Open battery power circuit of main fan relay
5 | Is drive belt okay? | Yes | Go to next step.
No | Replace drive belt.
6 | Perform EGR system inspection. Is EGR system okay? | Yes | Go to next step.
No | Repair or replace malfunctioning part according to EGR system operation results.
7 | Inspect EGR water cooler for followings: • Coolant passage clogging/restriction • Exhaust gas clogging/restriction Is EGR water cooler okay? | Yes | Go to next step.
No | Service as necessary.
8 | Perform coolant heater system inspection. (See THERMOSTAT INSPECTION.) Is coolant heater system okay? | Yes | Go to next step.
No | Repair or replace malfunctioning part according to coolant heater system operation results.
9 | Cool down engine. Remove thermostat and inspect operation. Is thermostat okay? | Yes | Thermostat is okay. Inspect cylinder block for leakage or blockage.
No | Replace thermostat.
10 | Verify test results. • If okay, return to diagnostic index to service any additional symptoms. • If malfunction remains, replace PCM. (See PCM REMOVAL/INSTALLATION [MZR-CD (RF Turbo)].)