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Home >> Mercury >> 2010 >> Milan Base, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 971 (Climate Control System - General Information And Diagnostics - (Hybrid)) >> Diagnostic Tests >> Climate Control System >> Pinpoint Tests >> Pinpoint Test D: Insufficient, Erratic or No Heat >> Pinpoint Test D: Insufficient, Erratic Or No Heat

Pinpoint Test D: Insufficient, Erratic Or No Heat

WARNING: This page is about a different car, the 2007 Mercury Mariner and 2007 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
  1. D1 USE THE RECORDED DTCs FROM THE PCM SELF-TEST 
    • Using the recorded results from the PCM self-test:
    • Is DTC P2600 retrieved? 
    1. YES  : REFER to INTRODUCTION -- HYBRID ENGINES article to continue diagnosis of the electric coolant pump.
    2. NO  : Go to  D2.
  2. D2 CHECK FOR CORRECT ENGINE COOLANT LEVEL 
    • Key in OFF position.
    • Check the engine coolant level at hot and cold temperatures.
    • Is the engine coolant at the correct level (hot/cold) in the radiator coolant recovery reservoir? 
    1. YES  : Go to  D4.
    2. NO  : Go to  D3.
  3. D3 CHECK THE COOLANT SYSTEM INCLUDING THE RADIATOR CAP FOR LEAKS 
    • Fill the engine cooling system to the specified level.
    • Pressure check the engine cooling system. Refer to ENGINE COOLING - HYBRID article. It is not necessary to check components separately at this time.
    • Does the engine cooling system, including the radiator cap, hold pressure? 
    1. YES  : The system is operating normally at this time. The concern may have been caused by a low coolant level.
    2. NO  : REPAIR the engine cooling system. REFER to ENGINE COOLING - HYBRID article. TEST the system for normal operation.
  4. D4 CHECK FOR HOT WATER TO THE HEATER CORE INLET HOSE 
    WARNING: The heater core hoses become too hot to handle and may cause serious burns if the system is working correctly.
    • Set the climate control to the warmest setting and the fan speed to the highest setting.
    • Start the engine and allow the engine to reach normal operating temperature.
      • Fig 1: Heater Core Inlet Hose
      GF0025640Courtesy of FORD MOTOR CO.
    • Feel the heater core inlet hose.
    • Is the heater core inlet hose too hot to handle? 
    1. YES  : Go to  D5.
    2. NO  : Go to  D6.
  5. D5 CHECK THE HEATER CORE OUTLET HOSE FOR HOT WATER 
      Fig 2: Heater Core Outlet Hose
      GF0025641Courtesy of FORD MOTOR CO.
    • Feel the heater core outlet hose.
    • Is the heater core outlet hose warm/hot? 
    1. YES  : REFER to CLIMATE CONTROL SYSTEM - GENERAL INFORMATION AND DIAGNOSTICS article and diagnose for inoperative temperature control.
    2. NO  : INSTALL a new heater core. REFER to CLIMATE CONTROL article. TEST the system for normal operation.
  6. D6 CHECK CIRCUIT 776 (OG/BK) FOR VOLTAGE 
    • Key in OFF position.
    • Disconnect: Heater Pump Motor C1465
    • Key in ON position.
      • Fig 3: Checking Circuit For Voltage
      GF0025697Courtesy of FORD MOTOR CO.
    • Measure the voltage between ground and heater pump motor C1465-2, circuit 776 (OG/BK).
    • Is the voltage greater than 10 volts? 
    1. YES  : Go to  D7.
    2. NO  : CARRY OUT the heater pump motor relay component test. Refer to COMPONENT TESTING article. If the relay test OK, go to  D8.
  7. D7 CHECK CIRCUIT 57 (BK) FOR GROUND 
      Fig 4: Checking Circuit For Open
      GF0025243Courtesy of FORD MOTOR CO.
    • Measure the resistance between ground and heater pump motor C1465-2, circuit 57 (BK).
    • Is the resistance less than 5 ohms? 
    1. YES  : INSTALL a new heater pump motor. TEST the system for normal operation.
    2. NO  : REPAIR circuit 57 (BK) for an open. TEST the system for normal operation.
  8. D8 CHECK FOR VOLTAGE TO THE HEATER PUMP MOTOR RELAY 
    • Key in OFF position.
    • Disconnect: Heater Pump Motor Relay
    • Key in ON position.
      • Fig 5: Checking Circuit For Voltage
      GF0025698Courtesy of FORD MOTOR CO.
    • Measure the voltage between ground and the heater pump motor relay socket:
      • pin 30, circuit 583 (YE).
      • pin 86, circuit 361 (RD).
    • Are the voltages greater than 10 volts? 
    1. YES  : Go to  D9.
    2. NO  : VERIFY battery junction box (BJB) fuse 2 (10A) and 6 (15A) are OK. If OK, REPAIR circuit 361 (RD) or 583 (YE) for an open. TEST the system for normal operation.
  9. D9 CHECK THE HEATER PUMP MOTOR RELAY PCM OUTPUT 
      Fig 6: Checking Circuit For Voltage
      GF0025699Courtesy of FORD MOTOR CO.
    • Measure the voltage between heater pump motor relay socket pin 86, circuit 361 (RD) and pin 85, circuit 1421 (DG/OG).
    • Is the voltage greater than 10 volts? 
    1. YES  : REPAIR circuit 776 (OG/BK) for an open. TEST the system for normal operation.
    2. NO  : Go to  D10.
  10. D10 CHECK CIRCUIT 1421 (DG/OG) FOR AN OPEN 
    • Key in OFF position.
    • Disconnect: PCM C175t
      • Fig 7: Checking Circuit For Open
      GF0025700Courtesy of FORD MOTOR CO.
    • Measure the resistance between PCM C175t-23, circuit 1421 (DG/OG) and heater pump motor relay pin 85, circuit 1421 (DG/OG).
    • Is the resistance less than 5 ohms? 
    1. YES  : Go to  D11.
    2. NO  : REPAIR circuit 1421 (DG/OG) for an open. TEST the system for normal operation.
  11. D11 CHECK THE PCM CONNECTION 
    • Check the DTCs.
    • Disconnect all the PCM connectors.
    • Check for:
      • corrosion.
      • pushed-out pins.
      • incorrectly seated connector.
    • Connect and correctly seat all the PCM connectors.
    • Operate the system.
    • Does the concern return? 
    1. YES  : INSTALL a new PCM. TEST the system for normal operation.
    2. NO  : The system is operating correctly at this time. The concern may have been cause by a loose or corroded connector.
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