Inspection and Verification
- Verify the customer concern.
- Visually inspect for obvious signs of damage and system integrity. Visual Inspection Mechanical Electrical Leaks Coolant expansion tank Electric fan Radiator Fuse Wiring harness Loose or corroded connector(s) Engine Coolant Temperature (ECT) sensor
- If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
- If there are clear symptoms refer to the table below, alternatively, check for Diagnostic Trouble Codes (DTCs) and refer to the DTC Index.
Symptom Chart
| Symptom | Possible Cause | Action |
|---|---|---|
| Coolant loss | Hoses Hose connections Radiator Coolant pump Heater core Gaskets Engine casting cracks Engine block core plugs | Refer to Pinpoint Test A . |
| Engine overheating | Engine coolant (level/condition) Thermostat Fan motor Fan motor fuses and/or circuits ECT sensor Engine control module (ECM) Fan speed module | Refer to Pinpoint Test B . |
| Engine not reaching normal operating temperature | Thermostat Electric fan Fan speed module | Refer to Pinpoint Test C . |
DTC Index
| CAUTION | When probing connectors to take measurements in the course of the pinpoint tests, use the adaptor kit, part number 3548-1358-00. |
Note. Generic scan tools may not read the codes listed, or may read only five digit codes. Match the five digits from the scan tool to the first five digits of the seven digit code listed to identify the fault (the last two digits give extra information read by the manufacturer approved diagnostic system).
Note. When performing voltage or resistance tests, always use a digital multimeter (DMM) accurate to three decimal places, and with a current calibration certificate. When testing resistance, always take the resistance of the DMM leads into account.
Note. Check and rectify basic faults before beginning diagnostic routines involving pinpoint tests.
Note. If DTCs are recorded and, after performing the pinpoint tests, a fault is not present, an intermittent concern may be the cause. Always check for loose connections and corroded terminals.
| DTC | Description | Possible Cause | Action |
|---|---|---|---|
| P011623 | Engine Coolant Temperature (ECT) sensor circuit - range/performance - signal stuck low | Low coolant level ECT sensor sensing circuit - intermittent high resistance Engine thermostat failure ECT sensor failure | Fill cooling system to correct level and specification. See Specifications . Carry out any pinpoint tests associated with this DTC using the manufacturer approved diagnostic system Check and install new engine thermostat as necessary. See Thermostat - Vehicles Without: Supercharger . Install a new ECT sensor as necessary. Refer to Engine Coolant Temperature (ECT) Sensor article. |
| P011624 | Engine Coolant Temperature (ECT) sensor circuit - range/performance - signal stuck high | Low coolant level ECT sensor sensing circuit - intermittent high resistance Engine thermostat failure ECT sensor failure | Fill cooling system to correct level and specification. See Specifications . Carry out any pinpoint tests associated with this DTC using the manufacturer approved diagnostic system Check and install new engine thermostat as necessary. See Thermostat - Vehicles Without: Supercharger . Install a new ECT sensor as necessary. Refer to Engine Coolant Temperature (ECT) Sensor article. |
| P011629 | Engine Coolant Temperature (ECT) sensor circuit - range/performance - signal invalid | Low coolant level ECT sensor sensing circuit - intermittent high resistance Engine thermostat failure ECT sensor failure | Fill cooling system to correct level and specification. See Specifications . Carry out any pinpoint tests associated with this DTC using the manufacturer approved diagnostic system Check and install new engine thermostat as necessary. See Thermostat - Vehicles Without: Supercharger . Install a new ECT sensor as necessary. Refer to Engine Coolant Temperature (ECT) Sensor article. |
| P011700 | Engine Coolant Temperature (ECT) sensor circuit - low input | ECT sensor sensing circuit - short to power, high resistance, open circuit, disconnected ECT sensor failure | Carry out any pinpoint tests associated with this DTC using the manufacturer approved diagnostic system Install a new ECT sensor as necessary. Refer to Engine Coolant Temperature (ECT) Sensor article. |
| P011800 | Engine Coolant Temperature (ECT) sensor circuit - high input | Engine overheat condition/cooling fan failure ECT sensor sensing circuit - short to ground ECT sensor failure | Check for cooling fan circuit DTCs and refer to relevant action specified in DTC Index Carry out any pinpoint tests associated with this DTC using the manufacturer approved diagnostic system Install a new ECT sensor as necessary. Refer to Engine Coolant Temperature (ECT) Sensor article. |
| P012500 | Insufficient coolant temperature for closed loop fuel control | Low coolant level ECT sensor sensing circuit - intermittent high resistance Engine thermostat failure ECT sensor failure | Fill cooling system to correct level and specification. See Specifications . Carry out any pinpoint tests associated with this DTC using the manufacturer approved diagnostic system Check and install new engine thermostat as necessary. See Thermostat - Vehicles Without: Supercharger . Install a new ECT sensor as necessary. Refer to Engine Coolant Temperature (ECT) Sensor article. |
| P012800 | Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature) | Low/contaminated coolant Thermostat Cooling fan circuit(s)/module | Refer to Pinpoint Test C . |
| P048023 | Electric fan control circuit low | Electric fan control circuit - short to ground, high resistance | Carry out any pinpoint tests associated with this DTC using the manufacturer approved diagnostic system |
| P048024 | Electric fan control circuit high | Electric fan control circuit - short to power | Carry out any pinpoint tests associated with this DTC using the manufacturer approved diagnostic system |
| P048309 | Fan rationality check | Cooling fan obstructed Fan/motor damaged | Carry out any pinpoint tests associated with this DTC using the manufacturer approved diagnostic system CLEAR any obstruction and INSTALL a new fan as necessary. See Cooling Fan Motor and Shroud - Vehicles Without: Supercharger . |
| P048316 | Fan rationality check | Fan control module reports battery voltage less than nine volts | Carry out any pinpoint tests associated with this DTC using the manufacturer approved diagnostic system CHECK the battery condition CHECK the charging system and fan circuits |
| P048317 | Fan rationality check | Fan control module reports battery voltage greater than 18 volts | Carry out any pinpoint tests associated with this DTC using the manufacturer approved diagnostic system CHECK the charging system and fan circuits |
| P048397 | Fan rationality check | Cooling fan jammed | Carry out any pinpoint tests associated with this DTC using the manufacturer approved diagnostic system CLEAR any obstruction and INSTALL a new fan as necessary. See Cooling Fan Motor and Shroud - Vehicles Without: Supercharger . |
Pinpoint Test A: LOSS OF COOLANT
Pinpoint Test A
A1
VISUAL INSPECTION
- Visually inspect for loss of coolant.
- Carry out a system pressure test. See «Component Tests»(ref-312545-S30811142632009041400000) .
Is the engine cooling system leaking?
YES Rectify the leak as indicated by the test result. Top-up and fill the cooling system to the correct level with the correct specification fluid as necessary. See «Specifications»(ref-312545-S35595073432009041400000) and «Cooling System Draining, Filling and Bleeding - Vehicles Without: Supercharger»(ref-312545-S22371452422009041400000) . TEST the system for correct operation.
NO Verify the customer complaint.
Pinpoint Test B: THE ENGINE OVERHEATS
Pinpoint Test B
B1
CHECK COOLANT
- WARNING: The cooling system is pressurized! Ensure the reservoir cap is never released until the system has cooled. Failure to follow these instructions may result in personal injury.
- Check the coolant level and condition.
Does the system contain sufficient coolant of the correct specification?
YES Go to step 2 . → B2
NO Top-up and fill the cooling system to the correct level with the correct specification fluid as necessary. See «Specifications»(ref-312545-S35595073432009041400000) and «Cooling System Draining, Filling and Bleeding - Vehicles Without: Supercharger»(ref-312545-S22371452422009041400000) . Check for coolant loss. Refer to «Pinpoint Test A»(ref-312545-S40450787512009041400000) .
B2
CHECK COOLANT EXPANSION TANK PRESSURE CAP
- Check the coolant expansion tank pressure cap for damage/correct operation. REFER to the «Coolant Expansion Tank Pressure Cap Pressure Test»(ref-312545-S14608221922009041400000) .
Is the coolant expansion tank pressure cap operating correctly?
YES Go to step 3 . → B3
NO INSTALL a new coolant expansion tank pressure cap. TEST the system for correct operation.
B3
CHECK THERMOSTAT
- Check the thermostat for correct operation. REFER to the «Thermostat Test»(ref-312545-S01773825342009041400000) .
Is the thermostat operating correctly?
YES Check for correct operation of cooling fans, circuits, sensors, modules, etc. Refer to «Electronic Engine Controls»(ref-312551-S19403916762009041400000) article.
NO INSTALL a new thermostat. See «Thermostat - Vehicles Without: Supercharger»(ref-312545-S09078879672009041400000) . TEST the system for correct operation.
Pinpoint Test C: THE ENGINE DOES NOT REACH NORMAL OPERATING TEMPERATURE
Pinpoint Test C
C1
CHECK THERMOSTAT
- Check the thermostat for correct operation. REFER to the «Thermostat Test»(ref-312545-S01773825342009041400000) .
Is the thermostat operating correctly?
YES Check for correct operation of cooling fans, circuits, sensors, modules, etc. Refer to «Electronic Engine Controls»(ref-312551-S19403916762009041400000) article.
NO INSTALL a new thermostat. See «Thermostat - Vehicles Without: Supercharger»(ref-312545-S09078879672009041400000) . TEST the system for correct operation.
Cooling System Pressure Test
| WARNING | Never, under any circumstances, remove the coolant expansion tank pressure cap while the engine is operating. To avoid having scalding hot water or steam blow out of the cooling system, use extreme care when removing the coolant expansion tank pressure cap from a hot cooling system. Wait until the engine has cooled, then wrap a thick cloth around the coolant expansion tank pressure cap and turn it slowly until the pressure begins to release, step back while the pressure is released from the system. When certain all the pressure has been released (still with a cloth) turn and remove the coolant expansion tank pressure cap. Failure to follow these instructions may result in damage to the cooling system, engine and/or cause personal injury. |
- Switch the engine off.
- Open the hood and install protective fender covers.
- Carefully remove the coolant expansion tank pressure cap from the coolant expansion tank to relieve pressure in the cooling system. Add coolant to coolant expansion tank as necessary.
- Install the pressure tester equipment to the cooling system following manufacturers instructions. Reinstall the coolant expansion tank pressure cap (if pressure test equipment is not installed to the coolant expansion tank).
- Pressurize the cooling system to the coolant expansion tank pressure cap lower limit.
- Observe the gauge reading for approximately two minutes. Pressure should not drop during this time. If system holds pressure, continue from step 8. If the pressure drops, check the complete cooling system for leaks. Also refer to engine system checks if a leak cannot be located in the cooling system. Correct any leaks found and recheck the system.
- Release the system pressure and remove the pressure test equipment. Check the coolant level. Replenish as necessary with the correct coolant solution. See «Specifications»(ref-312545-S35595073432009041400000) .
- Check the radiator overflow hose for any obstructions which may block the flow of coolant either to or from the coolant expansion tank.
- Conduct the «Coolant Expansion Tank Pressure Cap Pressure Test»(ref-312545-S14608221922009041400000) .
Coolant Expansion Tank Pressure Cap Pressure Test
| WARNING | Never, under any circumstances, remove the coolant expansion tank pressure cap while the engine is operating. To avoid having scalding hot water or steam blow out of the cooling system, use extreme care when removing the coolant expansion tank pressure cap from a hot cooling system. Wait until the engine has cooled, then wrap a thick cloth around the coolant expansion tank pressure cap and turn it slowly until the pressure begins to release, step back while the pressure is released from the system. When certain all the pressure has been released (still with a cloth) turn and remove the coolant expansion tank pressure cap. Failure to follow these instructions may result in damage to the cooling system, engine and/or cause personal injury. |
- Remove the expansion tank pressure cap from the coolant expansion tank.
- Use water to clean cap in area of rubber seal and vacuum relief valve. Following manufacturers instructions, install the coolant expansion tank pressure cap to the pressure tester.
- Slowly pressurize the system until the pressure gauge reading stops increasing, and note highest pressure reading obtained.
- Release pressure and repeat Step 3 at least twice to make sure the pressure test reading is repeatable and within specification.
- If the pressure test gauge readings are not within specification, install a new coolant expansion tank pressure cap.
Thermostat Test
Remove the thermostat See Thermostat - Vehicles Without: Supercharger . Inspect for visible damage, note its opening temperature and immerse it in water. Heat the water until this temperature is reached. The thermostat should begin to open. If it does not begin to open, install a new thermostat and see Thermostat - Vehicles Without: Supercharger . If thermostat begins to open, continue to heat the water until the thermostat fully opens, 5.8 mm (0.2 in) or more off the seat. If it does not fully open, install a new thermostat and see Thermostat - Vehicles Without: Supercharger .
Radiator Leak Test - Removed from the Vehicle
| CAUTION | Do 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. If a separate tank is not available, drain and rinse the test tank before testing an aluminum radiator. |
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.