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Engine Cooling: Diagnosis Ford Focus I рестайлинг

Cooling System (Mechanical) 17 illustrations ~2364 words

Inspection and Verification

  1. Verify the customer concern by operating the system.
  2. Visually inspect for obvious signs of mechanical or electrical damage. VISUAL INSPECTION REFERENCE Mechanical Electrical Leaks Coolant expansion tank Electric fan(s) Radiator Coolant pump Accessory drive belt Fuse Wiring harness Loose or corroded connector(s) Cylinder head temperature (CHT) sensor
  3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
  4. If the concern is not visually evident, verify the symptom and GO to «SYMPTOM CHART»(ref-207748-S21770092502005120100000) .

Symptom Chart

ConditionPossible SourcesAction
Loss of coolantHoses. Hose connections. Radiator. Coolant pump. Coolant expansion tank. Heater core. Gaskets. Engine casting cracks. Engine block core plugs.Go To PINPOINT TEST A .
The engine overheatsEngine coolant loss. Towing weight exceeded. System restriction. Blocked radiator grille. Thermostat. Fuse. Circuit. Fan motor. Coolant pump. Accessory drive belt. Cylinder head temperature (CHT) sensor. Powertrain control module (PCM).Go To PINPOINT TEST B .
The engine does not reach normal operating temperatureThermostat.Go To PINPOINT TEST C .
The cooling fan(s) is inoperativeFuse(s). Circuitry. Cooling fan motor.Go To PINPOINT TEST D .
The cooling fans are on at all timesFuse(s). Circuitry. Low speed fan relay. High speed fan relay.Go To PINPOINT TEST E .
The cooling fans operate in one speed onlyFuse(s). Circuitry. Low speed fan relay. High speed fan relay. Cooling fan resistor.Go To PINPOINT TEST F .
The run on fan (ROF) is inoperativeFuse(s). Circuitry. High speed fan relay. ROF thermo-switch.Go To PINPOINT TEST G .
The LH fan operates only in high speed and the RH fan operates only in low speedCircuitry.REPAIR splice S1002 for an open.

DIAGNOSTIC REFERENCE

PINPOINT TEST A: LOSS OF COOLANT

A1 CHECK FOR COOLANT LEAKS

  1. Visually inspect for loss of coolant.
  2. Is the engine cooling system leaking?

Yes

REPAIR the components in question. REFER to the appropriate procedure.

No

CARRY OUT the Pressure Test. REFER to COMPONENT TESTS .

PINPOINT TEST B: THE ENGINE OVERHEATS

B1 CHECK THE COOLANT

WARNINGNever remove the expansion tank cap under any circumstances while the engine is operating. Failure to follow these instructions can result in damage to the cooling system of the engine and may cause personal injury. To avoid having scalding hot water or steam blow out of the cooling system, use extreme care when removing the expansion tank cap from a hot cooling system. Wait until the engine has returned to outside air temperature, then wrap a thick cloth around the expansion tank cap and turn it slowly until the pressure begins to release. Step back while the pressure is released from the cooling system. When certain all the pressure has been released (still with a cloth) turn and remove the expansion tank cap. Failure to follow these instructions can result in personal injury.
  1. Inspect the coolant level and condition.
  2. Is the coolant OK?

Yes

GO to B2.

No

If coolant is weak or contaminated, FLUSH and REFILL with new coolant as necessary. If the coolant is low, REFILL the system and CARRY OUT the Component Test. REFER to COMPONENT TESTS .

B2 CHECK THE THERMOSTAT

  1. Carry out the «COMPONENT TEST»(ref-207748-S06372774502005120100000) .
  2. Is the thermostat OK?

Yes

Go To PINPOINT TEST D for inoperative cooling fan(s).

No

INSTALL a new thermostat. REFER to THERMOSTAT - SVT , THERMOSTAT - 2.0L ZETEC , THERMOSTAT - 2.0L SPI or THERMOSTAT HOUSING - 2.3L .

PINPOINT TEST C: THE ENGINE DOES NOT REACH NORMAL OPERATING TEMPERATURE

C1 CHECK THE THERMOSTAT

  1. Carry out the «COMPONENT TEST»(ref-207748-S06372774502005120100000) .
  2. Is the thermostat OK?

Yes

REFER to INTRODUCTION - CNG, FLEX-FUEL & GASOLINE .

No

INSTALL a new thermostat. REFER to THERMOSTAT - SVT , THERMOSTAT - 2.0L ZETEC , THERMOSTAT - 2.0L SPI or THERMOSTAT HOUSING - 2.3L .

PINPOINT TEST D: THE COOLING FAN(S) IS INOPERATIVE

Note. Before carrying out the following test, diagnose any PCM DTCs.

D1 CHECK FOR FAN OPERATION

  1. Key in ON position.
  2. Enter the following diagnostic mode on the diagnostic tool: Low Speed Fan Relay Active Command.
  3. Command the low speed fan relay ON.
  4. Does either fan operate?

Yes

GO to D3.

No

GO to D2.

D2 CHECK CIRCUIT 31-PA6 (BK) FOR GROUND

Scheme 5

Scheme 5
Scheme 5
  1. Key in OFF position.
  2. Disconnect: LH Cooling Fan C1048.
  3. Measure the resistance between the LH cooling fan C1048 pin 1, circuit 31-PA6 (BK) and ground.
  4. Is the resistance less than 5 ohms?

Yes

REPAIR circuit 30-PA1 (RD) for an open. TEST the system for normal operation.

No

REPAIR circuit 31-PA6 (BK) for an open. TEST the system for normal operation.

D3 CHECK CIRCUIT 31-PA6 (BK) OR CIRCUIT 31-PA16 (BK) FOR GROUND

Scheme 6

Scheme 6
Scheme 6
  1. Key in OFF position.
  2. Disconnect: Inoperative Cooling Fan.
  3. Measure the resistance between the inoperative cooling fan (LH) C1048 pin 1, circuit 31-PA6 (BK) or (RH) C1406 pin 1, circuit 31-PA16 (BK) and ground.
  4. Is the resistance less than 5 ohms?

Yes

GO to D4.

No

REPAIR circuit 31-PA6 (BK) or 31-PA16 (BK) for an open. TEST the system for normal operation.

D4 CHECK FOR VOLTAGE TO COOLING FAN MOTOR

Scheme 7

Scheme 7
Scheme 7
  1. Key in ON position.
  2. Enter the following diagnostic mode on the diagnostic tool: Low Speed Fan Relay Active Command.
  3. Command the high speed fan relay ON.
  4. Measure the voltage between the inoperative cooling fan (LH) C1048 pin 2, circuit 15S-PA6 (GN/YE) or (RH) C1406 pin 2, circuit 15S-PA16 (GN/OG) and ground.
  5. Is the voltage greater than 10 volts?

Yes

INSTALL a new cooling fan motor. TEST the system for normal operation.

No

REPAIR circuit 15S-PA6 (GN/YE) or 15S-PA16 (GN/OG) for an open. TEST the system for normal operation.

PINPOINT TEST E: THE COOLING FANS ARE ON AT ALL TIMES

Note. Before carrying out the following test, diagnose any PCM DTCs.

E1 CHECK THE FAN SPEED

  1. Key in ON position.
  2. Do the fans run continuously in LOW speed?

Yes

GO to E2.

No GO to E3.

E2 CHECK CIRCUIT 15S-PA9 (GN/WH)/15S-PA7A (GN/BU) FOR A SHORT TO VOLTAGE

  1. Key in OFF position.
  2. Disconnect: Low Speed Fan Relay.
  3. Key in ON position.
  4. Do the fans run continuously in LOW speed?

Yes

REPAIR circuit 15S-PA9 (GN/WH)/15S-PA7A (GN/BU) for a short to voltage. TEST the system for normal operation.

No

INSTALL a new low speed fan relay. TEST the system for normal operation.

E3 CHECK CIRCUIT 15S-PA6 (GN/YE)/15S-PA1 (GN/BU) OR 15S-PA16 (GN/OG)/15S-PA2 (GN/BU) FOR A SHORT TO VOLTAGE

  1. Key in OFF position.
  2. Disconnect: High Speed Fan Relay.
  3. Key in ON position.
  4. Do the fans run continuously?

Yes

REPAIR circuit 15S-PA6 (GN/YE)/15S-PA1 (GN/BU) or 15S-PA16 (GN/OG)/15S-PA2 (GN/BU) for a short to voltage. TEST the system for normal operation.

No

INSTALL a new high speed fan relay. TEST the system for normal operation.

PINPOINT TEST F: THE COOLING FANS OPERATE IN ONE SPEED ONLY

Note. Before carrying out the following test, diagnose any PCM DTCs.

F1 CHECK FOR FAN LOW SPEED OPERATION

  1. Key in ON position.
  2. Enter the following diagnostic mode on the diagnostic tool: Low Speed Fan Relay Active Command.
  3. Command the low speed fan relay ON.
  4. Command the high speed fan relay ON.
  5. Do the fans operate in low speed only?

Yes

GO to F2.

No

GO to F5.

F2 CHECK CIRCUIT 91-PA47 (BK/RD) FOR GROUND

Scheme 8

Scheme 8
Scheme 8
  1. Key in OFF position.
  2. Disconnect: High Speed Fan Relay.
  3. Measure the resistance between the high speed fan relay pin 6, circuit 91-PA47 (BK/RD) and ground.
  4. Is the resistance less than 5 ohms?

Yes

GO to F3.

No

REPAIR circuit 91-PA47 (BK/RD) for an open. TEST the system for normal operation.

F3 CHECK CIRCUIT 30-PA18 (RD) FOR VOLTAGE

Scheme 9

Scheme 9
Scheme 9
  1. Key in ON position.
  2. Measure the voltage between the high speed fan relay pin 3, circuit 30-PA18 (RD) and ground.
  3. Is the voltage greater than 10 volts?

Yes

GO to F4.

No

REPAIR circuit 30-PA18 (RD) for an open. TEST the system for normal operation.

F4 CHECK CIRCUIT 15S-PA1 (GN/BU) FOR AN OPEN

Scheme 10

Scheme 10
Scheme 10
  1. Key in OFF position.
  2. Disconnect: Cooling Fans C1048 and C1406.
  3. Measure the resistance between the LH cooling fan C1048 pin 2, circuit 15S-PA6 (GN/YE) and the high speed fan relay pin 5, circuit 15S-PA1 (GN/BU).
  4. Is the resistance less than 5 ohms?

Yes

INSTALL a new high speed fan relay. TEST the system for normal operation.

No

REPAIR circuit 15S-PA6 (GN/YE)/15S-PA1 (GN/BU) for an open. TEST the system for normal operation.

F5 CHECK CIRCUIT 30-PA8 (RD) FOR VOLTAGE

Scheme 11

Scheme 11
Scheme 11
  1. Key in OFF position.
  2. Disconnect: Low Speed Fan Relay.
  3. Key in ON position.
  4. Measure the voltage between the low speed fan relay pin 3, circuit 30-PA8 (RD) and ground.
  5. Is the voltage greater than 10 volts?

Yes

GO to F6.

No

REPAIR circuit 30-PA8 (RD) for an open. TEST the system for normal operation.

F6 CHECK CIRCUIT 15S-PA7A (GN/BU)/15S-PA9 (GN/WH) FOR AN OPEN

Scheme 12

Scheme 12
Scheme 12
  1. Key in OFF position.
  2. Disconnect: Cooling Fan Resistor C1027.
  3. Measure the resistance between the low speed fan relay pin 5, circuit 15S-PA7A (GN/BU) and the cooling fan resistor C1027 pin 1, circuit 15S-PA9 (GN/WH).
  4. Is the resistance less than 5 ohms?

Yes

GO to F7.

No

REPAIR circuit 15S-PA7A (GN/BU)/15S-PA9 (GN/WH) for an open. TEST the system for normal operation.

F7 CHECK CIRCUIT 15S-PA6 (GN/YE)/15S-PA2 (GN/BU) FOR AN OPEN

Scheme 13

Scheme 13
Scheme 13
  1. Disconnect: Cooling Fans C1048 and C1406.
  2. Measure the resistance between the LH cooling fan C1048 pin 2, circuit 15S-PA6 (GN/YE) and the cooling fan resistor C1027 pin 2, circuit 15S-PA2 (GN/BU).
  3. Is the resistance less than 5 ohms?

Yes

GO to F8.

No

REPAIR circuit 15S-PA6 (GN/YE)/15S-PA2 (GN/BU) for an open. TEST the system for normal operation.

F8 CHECK THE COOLING FAN RESISTOR

Scheme 14

Scheme 14
Scheme 14
  1. Connect: Cooling Fans C1048 and C1406.
  2. Place a fused jumper between the low speed fan relay pin 3, circuit 30-PA8 (RD) and pin 5, circuit 15S-PA7A (GN/BU).
  3. Key in ON position.
  4. Do the fans operate in low speed?

Yes

INSTALL a new low speed fan relay. TEST the system for normal operation.

No

INSTALL a new cooling fan resistor. TEST the system for normal operation.

PINPOINT TEST G: THE RUN ON FAN (ROF) IS INOPERATIVE

Note. Before carrying out the following test, diagnose any PCM DTCs.

G1 CHECK CIRCUIT 91-PA47 (BK/RD) FOR AN OPEN

Scheme 15

Scheme 15: PINPOINT TEST G: THE RUN ON FAN (ROF) IS INOPERATIVE
Scheme 15: PINPOINT TEST G: THE RUN ON FAN (ROF) IS INOPERATIVE
  1. Disconnect: High Speed Fan Relay.
  2. Measure the resistance between the high speed fan relay pin 6, circuit 91-PA47 (BK/RD) and ground.
  3. Is the resistance less than 5 ohms?

Yes

GO to G2.

No

REPAIR circuit 91-PA47 (BK/RD) for an open. TEST the system for normal operation.

G2 CHECK CIRCUIT 31-PA12 (BK) FOR AN OPEN

Scheme 16

Scheme 16
Scheme 16
  1. Disconnect: ROF Thermo-Switch C1412.
  2. Measure the resistance between the ROF thermo-switch C1412 pin 2, circuit 31-PA12 (BK) and ground.
  3. Is the resistance less than 5 ohms?

Yes

GO to G3.

No

REPAIR circuit 31-PA12 (BK) for an open. TEST the system for normal operation.

G3 CHECK CIRCUIT 31S-PA12 (BK/YE) FOR AN OPEN

Scheme 17

Scheme 17
Scheme 17
  1. Measure the resistance between the ROF thermo-switch C1412 pin 1, circuit 31S-PA12 (BK/YE) and the high speed fan relay pin 7, circuit 31S-PA12 (BK/YE).
  2. Is the resistance less than 5 ohms?

Yes

GO to G4.

No

REPAIR circuit 31S-PA12 (BK/YE) for an open. TEST the system for normal operation.

G4 CHECK THE ROF THERMO-SWITCH

Scheme 18

Scheme 18
Scheme 18
  1. Connect: High Speed Fan Relay.
  2. Place a fused jumper between the ROF thermo-switch C1412 pin 1, circuit 31S-PA12 (BK/YE) and pin 2, circuit 31-PA12 (BK).
  3. Key in ON position.
  4. Connect the diagnostic tool.
  5. Command the cooling fans ON in low speed then in high speed.
  6. Key in OFF position.
  7. Do the fans continue to operate after the ignition is turned OFF?

Yes

INSTALL a new ROF thermo-switch. TEST the system for normal operation.

No

INSTALL a new high speed fan relay. TEST the system for normal operation.

Pressure Test

  1. Switch the engine off.
  2. Open the hood and install protective fender covers.
  3. Install the adapter fitting from the Pressure Tester tightly, between the overflow/air purge nipple and the overflow/air purge hose at the coolant expansion tank. Reinstall the coolant expansion tank cap.
  4. Attach the pressure pump and gauge to the adapter fitting and pressurize the cooling system to the coolant expansion tank cap lower limit.
  5. Pressurize the cooling system. Observe the gauge reading for approximately two minutes. Pressure should not drop during this time. If the system holds pressure, proceed to Step 8. If the pressure drops, check for leaks at the engine to heater core hoses, engine to radiator hoses, bypass hose, coolant valve hose (if applicable), thermostat housing gasket, radiator and heater core, etc. If a leak cannot be located in the cooling system, repair any engine system related concerns as necessary. Correct any leaks found and recheck the system.
  6. Release the system pressure by loosening the coolant expansion tank cap. Check the coolant level. Replenish as necessary with the correct coolant solution.
  7. Conduct the coolant expansion tank cap «PRESSURE TEST»(ref-207748-S11562253612005120100000) .
  8. Release pressure by turning the pressure relief screw counterclockwise. Then, tighten the pressure relief screw and repeat Step 5 at least twice to make sure the pressure test reading is repeatable and within acceptable gauge reading limits of the coolant expansion tank cap.
  9. If the pressure test gauge readings are not within acceptable gauge reading limits, install a new coolant expansion tank cap.

Thermostat Test

A new thermostat should be installed only after the following tests have been carried out.

Thermostat Test, Electrical

WARNINGAlways vent the exhaust to the outside when carrying out this test. Failure to follow this instruction can result in personal injury.

Note. On vehicles with 98°C (208°F) electronic thermostats, the thermostat must be removed to access the terminals. Once the thermostat has been removed, check the resistance between the terminals. The resistance should measure 15 ohms +/- 2 ohms or a new thermostat must be installed.

Note. Procedure is most accurate if carried out indoors at less than 37.8°C (100°F) ambient air. This test may be carried out with or without the hood open and with the engine warm or cold.

  1. Check the coolant level in the radiator and engine coolant expansion tank. Fill as required.
  2. With the engine OFF, disconnect the cylinder head temperature (CHT) sensor electrical connector and attach the service coolant temperature monitor harness as a jumper between the PCM and the CHT. Attach a digital multimeter to the thermostat monitor harness. Voltage values (0 to 5 V) may now be monitored while the sensor retains its connection to the harness. A scan tool can also be used to monitor the CHT on vehicles equipped with a data link connector (DLC).

Thermostat Test, Mechanical

Note. Fully open means the thermostat valve lifts a distance of 5.8 mm (0.22 in) or more off the valve seat.

Remove the thermostat and immerse in a hot antifreeze and water mixture. The thermostat will open when the mixture has reached the standard operating (STO) temperature +/- 2°. The STO temperature is marked on the thermostat. Install a new thermostat if it does not operate as specified.

The following STO temperature thermostats are available

  1. 82°C (180°F)
  2. 90°C (194°F) or
  3. 98°C (208°F)

If heat is not available, check the thermostat for leakage. Hold the thermostat up to a lighted background. Leakage of light around a new thermostat valve at room temperature indicates that a new thermostat should be installed. Some thermostats have a small leakage notch at one location on the perimeter of the thermostat valve. This is considered normal.

Radiator Leak Test, Removed From the Vehicle

CAUTIONDo not leak test an aluminum radiator in the same water that is used to leak test copper/brass radiators. Flux and caustic cleaners may be present in the test water which will corrode aluminum.

Clean the radiator before leak testing to prevent contamination of the test tank. Leak test the radiator in clean water with 138 kPa (20 psi) air pressure.

A separate clean test tank is recommended for aluminum radiators. If a separate tank is not available for aluminum radiator testing, rinse the test tank each time before testing an aluminum radiator.

Scheme 19

Scheme 19: Special Tool(s)
Scheme 19: Special Tool(s)

Scheme 20

Scheme 20: Draining
Scheme 20: Draining

Scheme 21

Scheme 21
Scheme 21
  1. Relieve the cooling system pressure by slowly turning the expansion tank cap a quarter of a turn.
  2. Remove the coolant expansion tank cap when all the pressure has been released. With the vehicle in NEUTRAL, position it on a hoist. For additional information, refer to «JACKING AND LIFTING»(ref-234418) .
  3. Remove the engine undershield.
  4. Open the radiator drain valve to drain the coolant.
  5. Close the drain valve when all the coolant has been drained from the system.
  6. Install the engine undershield (if equipped).
  7. Lower the vehicle.

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