2001 Chevrolet Corvette 2000-01 ENGINE COOLING Electric .

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2001 Chevrolet Corvette2000-01 ENGINE COOLING Electric Cooling Fans - Cars2000-01 ENGINE COOLINGElectric Cooling Fans - CarsMODEL IDENTIFICATIONNOTE:For electric cooling fan diagnosis on 2000 Prizm, see appropriateMANUAL A/C-HEATER SYSTEMS article.MODEL IDENTIFICATION - CARSBody Code (1)"C""E""F""G""H""J""K""M""N""S""V""W"ModelPark AvenueEldoradoCamaro & FirebirdAuroraBonneville & LeSabreCavalier & SunfireDeVille & SevilleMetroAlero, Grand Am & MalibuPrizmCateraCentury, Grand Prix, Intrigue, Lumina, Monte Carlo &Regal"Y"Corvette"J"Saturn "L" Series"Z"Saturn "S" Series(1) Vehicle body code is fourth character of VIN.DESCRIPTION & OPERATIONELECTRIC COOLING FAN CONTROLAll Models Except CateraAll FWD and some RWD vehicles use an electric cooling fan. The electric cooling fan is used forradiator and A/C condenser cooling. Cooling fan operates when A/C is on and when engineMYMonday, April 06, 2009 2:35:422:35:33 PMPage 1 2005 Mitchell Repair Information Company, LLC.

2001 Chevrolet Corvette2000-01 ENGINE COOLING Electric Cooling Fans - Carscoolant temperature exceeds a specific value. One or more cooling fan relays may be used. Forcooling fan relay location, see COOLING FAN RELAY LOCATION table.COOLING FAN RELAY LOCATIONApplication"C" BodyLocationRight Front Of EngineCompartment, In Fuse/Relay BlockMounted On Lower RadiatorSupportIn Underhood Fuse Block On RightSide Of Engine CompartmentIn Underhood Electrical Center, OnLeft Inner Fender PanelIn Underhood Fuse Block, OnRight Side Of Engine CompartmentIn Underhood Fuse Block, OnRight Side Of Engine CompartmentIn Underhood Fuse/Relay Block AtLeft Front Corner Of EngineCompartmentIn Underhood Junction Block, AtLeft Side Of Engine Compartment"E" Body"K" Body"F" Body"G" Body"H" Body"J" Body"N" Body"W" BodyExcept LuminaInside Electrical Center At RightSide Of Engine CompartmentInside Electrical Centers AtRight & Left Front Of EngineCompartmentIn ECM Housing, In Left Front OfEngine CompartmentIn Underhood Electrical Center InFront Of BatteryIn Engine Compartment Relay BoxNear BatteryLumina"V" Body"Y" BodyMetroPrizmFuse/Relay Block No. 1Left Front Of EngineCompartment, To Left Of AirCleanerMYMonday, April 06, 2009 2:35:33 PMPage 2 2005 Mitchell Repair Information Company, LLC.

2001 Chevrolet Corvette2000-01 ENGINE COOLING Electric Cooling Fans - CarsFuse/Relay Block No. 2Left Front Of EngineCompartment, To Left OfBatteryIn Cooling Fan Control Module,Next To BatteryIn Underhood Fuse Block, In LeftFront Of Engine CompartmentSaturn "L" SeriesSaturn "S" SeriresSCAN TOOLA variety of information is transmitted through Data Link Connector (DLC). This data istransmitted at a high frequency which requires the use of Tech 2 Scan Tool. Other types of scantools are available and may function and provide adequate information for diagnostic work.Always refer to scan tool manufacturer's instructions.TROUBLE SHOOTINGPRELIMINARY INFORMATIONThis article contains only the text required to test electric cooling fans. Other diagnosticinformation may be referenced while performing electric cooling fan diagnosis. See appropriateENGINE PERFORMANCE articles for complete information on engine control systems.Trouble shoot cooling fan using appropriate diagnostic information provided. For cooling fanrelay location, see COOLING FAN RELAY LOCATION table.To help save diagnostic time, always check for blown fuses or fusible links before proceedingwith any testing. If fuses are blown, locate and repair short circuit before replacing fuses. Ensureall related relay and wire harness connections are clean and tight. Repair as necessary. SeeWIRING DIAGRAMS for component, terminal and wire color identification.NOTE:Vehicles may be equipped with a PCM/ECM using an ElectronicallyErasable Programmable Read Only Memory (EEPROM). Whenreplacing PCM/ECM, the new PCM/ECM must be programmed.ELECTRIC COOLING FAN CIRCUIT DIAGNOSISTo help save diagnostic time, check cooling system fluid level, water pump belt condition andtension. Always check for blown fuses or fusible links before proceeding with any testing. If fusesare blown, locate and repair short circuit before replacing fuses. Ensure all related relay and wireMYMonday, April 06, 2009 2:35:34 PMPage 3 2005 Mitchell Repair Information Company, LLC.

2001 Chevrolet Corvette2000-01 ENGINE COOLING Electric Cooling Fans - Carsharness connections are clean and tight. Repair as necessary. See WIRING DIAGRAMS .WARNING: Vehicles may be equipped with a PCM using an ElectronicallyErasable Programmable Read Only Memory (EEPROM). Whenreplacing PCM, new PCM must be programmed.1.0L & 1.3L METRODescriptionCooling fan is controlled by Powertrain Control Module (PCM) through cooling fan relay basedon inputs from engine coolant temperature sensor. PCM turns on the cooling fan when coolanttemperature sensor rises above 208 F (97.5 C) and turns off cooling fan when coolanttemperature sensor drops less than 199 F (92.5 C). PCM controls cooling fan motor bygrounding cooling fan relay control circuit which closes fan relay contacts.Diagnosis1. Install scan tool. Turn ignition on, engine off. Verify ECT sensor reading is less than 194 F(90 C). If cooling fan is not operating, go to next step. If cooling fan is operating, go to step3.2. Turn ignition on, engine off. Using scan tool, clear DTCs. Command fan on and then off. Ifcooling fan operated when commanded on and shut off when commanded off, go toDIAGNOSTIC AIDS . If fan did not operate when commanded on and shut off whencommanded off, go to step 73. Ensure ECT is less than 194 F (90 C). Disconnect cooling fan relay located in relay boxnear battery. If cooling fan is not operating, go to next step. If cooling fan is operating, go tostep 5 .4. Using test light connected to battery voltage, probe cooling fan relay connector cavity No. 2(Blue wire). If test light illuminates, go to step 6 . If test light does not illuminate, go to step16 .5. Repair short to power in Blue or Blue/Red wire between cooling fan relay and cooling fanmotor. See WIRING DIAGRAMS . After repairs, go to step 19 .6. Check for short to ground in Blue wire between PCM and cooling fan relay. repair asnecessary. After repairs, go to step 19 . If repair was not necessary, go to step 17 .7. Turn ignition on. Using test light connected to ground, probe cooling fan relay cavity No. 1(Black/White wire). If test light illuminates, go to next step. If test light does not illuminate,go to step 14 .8. Using test light connected to ground, probe cooling fan relay cavity No. 4 (Black/BlueMYMonday, April 06, 2009 2:35:34 PMPage 4 2005 Mitchell Repair Information Company, LLC.

2001 Chevrolet Corvette2000-01 ENGINE COOLING Electric Cooling Fans - Cars9.10.11.12.13.14.15.16.17.18.19.wire). If test light illuminates, go to next step. If test light does not illuminate, go to step 15 .Connect a fused jumper between cooling fan relay connector cavities No. 3 (Blue/Red wire)and No. 4 (Black/White wire). If cooling fan operates, go to next step. If cooling fan doesnot operate, go to step 12 .Using test light connected to battery voltage, probe cooling fan connector cavity No. 2(Blue wire). Using scan tool, command cooling fan on. If test light illuminates, go to step16 . If test light does not illuminate, go to next step.Check for open in Blue wire between PCM and cooling fan relay. Repair as necessary.After repairs, go to step 19 . If repair was not necessary, go to step 17 .Check for open in Blue or Blue/Red wire between cooling fan relay and cooling fan motor.Repair as necessary. See WIRING DIAGRAMS . After repairs, go to step 19 . If repairwas not necessary, go to next step.Check for open or poor terminal contact in Black wire between cooling fan motor andground. Repair as necessary. After repairs, go to step 19 . If repair was not necessary, go tostep 18 .Repair open in Black/White wire between cooling fan relay terminal No. 1 and junctionblock. After repairs, go to step 19 .Repair open in Black/Blue wire between cooling fan relay terminal No. 4 and fuse box.After repairs, go to step 19 .Replace cooling fan relay. After repairs, go to step 19 .Replace PCM. After repairs, go to step 19 .Replace cooling fan motor. After repairs, go to next step.Using scan tool, clear any DTCs and road test vehicle within freeze frame conditions thatcaused DTC to set. If any DTCs set, go to appropriate DTC. See appropriate SELFDIAGNOSTICS article in ENGINE PERFORMANCE. If no DTCs are stored, system isokay at this time.Diagnostic AidsWhenever vehicle owner complains of an overheating problem, determine if complaint was dueto an actual boilover, or TEMP light or gauge indicated overheating. Whenever gauge or lightindicates overheating, but no boilover is detected, gauge or light circuit should be checked.Gauge accuracy can also be checked by comparing engine coolant temperature sensor readingwith gauge reading.If engine is actually overheating, and gauge indicates overheating, but cooling fan is not comingon, ECT sensor has probably shifted out of calibration and should be replaced. Whenever engineis overheating and cooling fan is on, cooling system should be checked.MYMonday, April 06, 2009 2:35:34 PMPage 5 2005 Mitchell Repair Information Company, LLC.

2001 Chevrolet Corvette2000-01 ENGINE COOLING Electric Cooling Fans - Cars1.8L PRIZMNOTE:For electric cooling fan diagnosis on 2000 Prizm, see appropriateMANUAL A/C-HEATER SYSTEMS article.DescriptionEngine cooling fan system consists of 2 electric cooling fans and 3 fan relays. Relays are arrangedin a series/parallel configuration that allows Powertrain Control Module (PCM) to operate bothfans together at low or high speeds. Cooling fans and fan relays receive battery voltage on 2individual power circuits, from fuse and relay block 1 and from junction block 2. During highspeed operation, which is when ECT reaches 199 F (93 C) or A/C system pressure exceeds 220psi, PCM removes ground for fan 1 and fan 2 relays through cooling fan relay control circuit.This de-energizes fan 2 relay which switches relay contacts and provides a ground path forauxiliary fan motor. At the same time, fan 1 relay is de-energized, closing relay contacts andproviding battery voltage on main fan motor supply voltage circuit to main fan motor.During low speed operation, which is when A/C is operating and Engine Coolant Temperature(ECT) is less than 181 F (83 C), PCM supplies ground path for fan 1 and fan 2 relays throughcooling fan relay control circuit. This energizes both relays, opens fan 1 relay contacts andswitches contacts in fan 2 relay. Engine main relay supplies battery voltage through cooling fanmotor supply voltage circuit to auxiliary fan motor. When A/C is operating, compressor clutch(MG) relay energizes fan 3 relay. Ground path for auxiliary fan motor is through switchedcontacts in fan 2 relay, through closed contacts of fan 3 relay and through main fan motor toground. Result is a series circuit with both fans running at low speed.During high speed fan operation, both engine cooling fans have their own power and ground path.Result is a parallel circuit with both fans running at high speed. A/C high pressure switch is inseries with PCM controlled ground for coils of fan 1 and fan 2 relays. If A/C system pressureexceeds 220 psi, pressure switch opens ground circuit to coils of fan 1 and 2 relays. This has sameeffect as if PCM had removed ground for relays. PCM will control ground for fan relays based oninput from ECT sensor in order to maintain cooling system at normal operating temperature.Main and auxiliary fan motors run at half speed in series configuration when all of the followingconditions occur: A/C system is operating.A/C system pressure is less than 178 psi.ECT is less than 181 F (83 C).MYMonday, April 06, 2009 2:35:34 PMPage 6 2005 Mitchell Repair Information Company, LLC.

2001 Chevrolet Corvette2000-01 ENGINE COOLING Electric Cooling Fans - CarsMain and auxiliary fan motors run at full speed in parallel configuration when either of thefollowing conditions occur: ECT reaches 199 F (93 C).A/C system pressure exceeds 220 psi.Main Cooling Fan Inoperative1. Review DESCRIPTION , and then go to next step.2. Run engine until operating temperature is reached and thermostat opens. If cooling fansoperate, problem is intermittent. If cooling fans do not operate, go to next step.3. Exchange fan 1 relay with known good relay (fan 3 relay, A/C MG relay, or horn relay). Ifproblem was found, repair as necessary. After repairs, go to step 14 . If problem was notfound, go to next step.4. Stop engine. Disconnect main fan motor connector. Connect test light across main fan motorconnector. Start engine. If test light illuminates, go to step 12 . If test light does notilluminate, go to next step.5. Check main fan motor ground circuit (White/Black wire) for open. If problem was found,repair as necessary. After repairs, go to step 14 . If problem was not found, go to next step.6. Check main fan motor supply voltage circuit (Black/Red wire) for open. If problem wasfound, repair as necessary. After repairs, go to step 14 . If problem was not found, go to nextstep.7. Check supply voltage circuit to fuse and relay block 1 for open. If problem was found,repair as necessary. After repairs, go to step 14 . If problem was not found, go to next step.8. Check fan 1 relay switch supply voltage circuit for open. If problem was found, repair asnecessary. After repairs, go to step 14 . If problem was not found, go to next step.9. Check engine main relay switch supply voltage circuit for open. If problem was found,repair as necessary. After repairs, go to step 14 . If problem was not found, go to next step.10. Check engine main relay control circuit (Black/Yellow wire) for open. If problem wasfound, repair as necessary. After repairs, go to step 14 . If problem was not found, go to nextstep.11. Remove fuse and relay block 1 from inner fender. Repair poor connections or highresistance in