FAULT CODE 482 Fuel Pressure Low - Data Valid but Below Normal Operational Range - Moderately Severe Level. Overview CODE REASON EFFECT Fault Code: 482 PID: P094 SPN: 94 FMI: 1/18 LAMP: Amber SRT: Fuel Pressure Low - Data Valid but Below Normal Operational Range - Moderately Severe Level. Engine may not start, white smoke, run rough, or lose power. Fuel System Circuit Circuit Description The gear pump draws fuel from the fuel tank through a suction fuel filter and an anti-drainback valve. The gear pump develops between 1724 and 2620 kPa [250 and 380 psi] of fuel pressure. The fuel flows through a pressure fuel filter and fuel shutoff valve to the fueling and timing actuators and rail fuel pressure sensor.
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FAULT CODE 482 Fuel Pressure Low - Data Valid but … CODE 482 Fuel Pressure Low - Data Valid but Below Normal Operational Range - Moderately Severe Level. Overview CODE REASON EFFECT
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FAULT CODE 482Fuel Pressure Low - Data Valid butBelow Normal Operational Range -
Fuel Pressure Low - DataValid but Below NormalOperational Range -Moderately Severe Level.
Engine may notstart, whitesmoke, runrough, or losepower.
Fuel System Circuit
Circuit Description
The gear pump draws fuel from the fuel tank through a suctionfuel filter and an anti-drainback valve. The gear pumpdevelops between 1724 and 2620 kPa [250 and 380 psi] offuel pressure. The fuel flows through a pressure fuel filter andfuel shutoff valve to the fueling and timing actuators and railfuel pressure sensor.
The fuel pressure is monitored by the ECM. If the rail fuelpressure is lower than an acceptable level for a given set ofengine operating conditions, the fault code is logged.
Troubleshooting Steps
STEPS SPECIFICATIONSSTEP1.
Check the fault codes.
STEP 1A. Check for anactive fault code.
Is Fault Code 227 active?
STEP2.
Check the fuel supply.
STEP 2A. Check thevehicle fuel tanks forfuel.
Is there fuel in the fueltanks?
STEP 2B. Check forfuel leaks.
Are there any visible fuelleaks?
STEP 2C. Check fuelinlet restriction.
Is the fuel inlet restrictionless than thespecifications listed?
STEP3.
Check the engineoperation.
STEP 3A. Crank theengine to see if itstarts.
Does the engine start?
STEP4.
Check fuel shutoffvalve operation.
STEP 4A. Check fuelshutoff valve operation.
Does the fuel shutoff valveoperate and is 12-VDCpresent at the terminal ofthe fuel shutoff valve whenthe keyswitch is turnedON?
STEP 4B. Check for amechanical restrictionof the fuel shutoffvalve.
Is debris present in thefuel shutoff valve or arethere signs the fuel shutoffvalve is restricting flow?
STEP5.
Check the fuel lift pumpoperation.
STEP 5A. Check thefuel lift pump foractivation at keyswitchON.
Does the fuel lift pump runwhen the keyswitch isturned ON?
STEP 5B. Check thefuel lift pump pressure.
Is positive fuel pressuregreater than 64 kPa [10psi] present when the liftpump is running?
STEP6.
Check the 1724 kPa[250 psi] fuel pressureregulator.
Is there more than 237 ml[8 oz] of fuel coming fromthe drain line while theengine is cranking for 15seconds and the fuelingand timing actuators aredisconnected from theengine harness?
Is the fuel pump (gearpump) pressure less than689 kPa [100 psi] crankingat 130 rpm for at least 10seconds after the fuelsystem is primed for 30seconds?
STEP9.
Check the fuelpressure.
STEP 9A. Measure therail fuel pressure.
Is the rail fuel pressure atleast 1448 kPa [210 psi] atidle?
Is there any amount of fuelcoming from the ECMcooling plate supply linewhile the engine iscranking and the fuelingand timing actuators aredisconnected from theengine harness?
Is more that 237 ml [8 oz]of fuel coming from thedrain line while the engineis cranking for 15 secondsand the fueling and timingactuators aredisconnected from theengine harness?
Inspect the fuel tanks, lines,and related components forleaks.
Inspect for fuel leaks.
Are there any fuel leaks in thetanks or the fuel supply lines?
Are there any fuel leaks in thetanks or the fuel supply lines?
YES NO
Locate and repair the sourceof the fuel leak by checkingall the engine and OEMsupply lines, fittings, suction-side fuel filter head, fuel tankstand pipes, ECM coolingplate, and ECM cooling platefuel supply and return lines.
No Repair
Go to 17A Go to 2C
Guided Step 2C - Check fuel inlet restriction.
Conditions
Connect vacuumgauge to the suctionside Compuchek™fittingTurn keyswitch ONEngine running at highidle (engine cranking iftroubleshooting No-Start).
Action
If the engine uses a primingpump, wait until the priming
Turn keyswitch OFFConnect the enginewiring harness to thefuel shutoff valve.
Action
Inspect the 1724 kPa [250psi] pressure regulator.
Disconnect the wiringharness from thefueling and timingactuators.Remove the fuel linethat connects thepressure fuel filterhead on the integratedfuel system module(IFSM) to the ECMcooling plate at the
cooling plate.Install a cap onto thefitting into the coolingplate to make sure noair is brought into thefuel system.Run the fuel line into abucket and crank theengine. If there is ameasurable amount offuel coming out of theline during cranking,then fuel is bypassingthe 1724 kPa [250 psi]regulator.
Is there any amount of fuelcoming from the ECM coolingplate supply line while theengine is cranking and thefueling and timing actuatorsare disconnected from theengine harness?
Is there any amount of fuelcoming from the ECM coolingplate supply line while theengine is cranking and thefueling and timing actuatorsare disconnected from theengine harness?
YES NO
Remove and inspect the 1724kPa [250 psi] pressureregulator for debris that canstick the regulator open andfor cut or missing o-rings.
Connect the enginewiring harness to thefuel shutoff valve.
Action
Inspect the 2620 kPa [380psi] pressure regulator.
Disconnect the OEMdrain line connection atthe integrated fuelsystem module (IFSM).Install a short piece ofhose to run into abucket.Disconnect the wiringharness from thefueling and timingactuators.Turn keyswitch ON andwait until the lift pumpstops running.Crank the engine for15 seconds andmeasure the fuel fromthe integrated fuelsystem module (IFSM)drain.
Is more than 237 ml [8 oz] offuel coming from the drain linewhile the engine is crankingfor 15 seconds and thefueling and timing actuatorsare disconnected from theengine harness?
Is more than 237 ml [8 oz] offuel coming from the drainline while the engine iscranking for 15 seconds andthe fueling and timingactuators are disconnectedfrom the engine harness?
YES NO
Remove and inspect the 2620kPa [380 psi] pressureregulator for debris that canstick the regulator open andfor cut or missing o-rings.
Guided Step 8A - Measure the fuel pump (gearpump) pressure while cranking.
Conditions
Connect a pressuregauge to theCompuchek™ fittingon the back of the fuelpump (gear pump)Turn keyswitch ONDisconnect the wire atthe fuel shutoff valve.
Action
Measure the fuel pump(gear pump) pressure whilecranking.
The fuel lift pump mustnot be running duringthis check. Wait 2minutes after thekeyswitch is turned ONor disconnect the 2-pinpower supply from thelift pump.
Note: The engine wiringharness must bedisconnected from the fuelshutoff valve during thisstep.
Measure the fuel pump(gear pump) pressurewhile cranking theengine.
Is the fuel pump (gear pump)pressure less than 689 kPa[100 psi] cranking at 130 rpmfor at least 10 seconds afterthe fuel system is primed for30 seconds?
Is the fuel pump (gear pump)pressure less than 689 kPa[100 psi] cranking at 130 rpmfor at least 10 seconds afterthe fuel system is primed for30 seconds?
Guided Step 9A - Measure the fuel pump (gearpump) pressure at idle.
Conditions
Connect allcomponentsTurn keyswitch ONStart the engine.
Action
Measure the fuel pump(gear pump) pressure atidle.
The fuel lift pump mustnot be running duringthis check. Wait 2minutes afterkeyswitch ON ordisconnect the 2-pinpower supply from thefuel lift pump.
Measure the fuel pump(gear pump) pressure.
With the enginerunning at high idle,use a pressure gaugeattached to theCompuchek™ fittingon the back of the fuelpump (gear pump) tomeasure the fuel pump(gear pump) pressure.
Is the fuel pump (gear pump) Is the fuel pump (gear pump)
Guided Step 9B - Measure the fuel pump (gearpump) pressure at high idle.
Conditions
Turn keyswitch ONStart the engine.
Action
Measure the fuel pump(gear pump) pressure athigh idle.
The fuel lift pump mustnot be running duringthis check. Wait 2minutes afterkeyswitch ON ordisconnect the 2-pinpower supply from thefuel lift pump.Measure the fuel pump(gear pump) pressurewith the enginerunning at high idleand no load.Measure the fuel pump(gear pump) pressurewith a pressure gaugeattached to theCompuchek™ fittingon the back of the fuelpump.
Is the fuel pump (gear pump)pressure a minimum of 1931kPa [280 psi] at 2000 rpm?
Is the fuel pump (gear pump)pressure a minimum of 1931kPa [280 psi] at 2000 rpm?
Guided Step 10 - Check the air in thepressure-side fuel.
Guided Step 10A - Check for air in the pressure-side fuel.
Conditions
Turn keyswitch OFF.
Action
Check for air in thepressure-side fuel.
Note: Possible sources of airin the pressure-side fuel areleaks in:
OEM supply linesFittingsSuction-side fuel filterheadFuel tank stand pipesECM cooling plateECM cooling plate fuelsupply and return lines.
Is air present in the pressure-side fuel?
Is air present in the pressure-side fuel?
YES NO
Locate and repair the sourceof the air leak by checking allthe OEM supply lines andfittings, suction-side fuel filterhead, fuel tank stand pipes,ECM cooling plate, and ECMcooling plate fuel supply andreturn lines.
Guided Step 11A - Measure the fuel inletrestriction.
Conditions
Connect allcomponentsTurn keyswitch ONStart the engine.
Action
Measure the fuel inletrestriction.
The fuel lift pump mustnot be running duringthis check. Wait 2minutes afterkeyswitch ON ordisconnect the 2-pinpower supply from thefuel lift pump.Check the fuel inletrestriction.Maximum clean filter:203 mm Hg [8 in Hg]Maximum dirty filter:305 mm Hg [12 in Hg]
Is the fuel inlet restriction lessthan the specification?
Is the fuel inlet restriction lessthan the specification?
YES NO
No RepairReplace the suction-side fuelfilter or repair the cause ofhigh inlet restriction.
Connect allcomponentsTurn keyswitch ONEngine running at highidle.
Action
Measure the pressure dropacross the pressure-sidefuel filter.
The fuel lift pump mustnot be running duringthis check. Wait 2minutes afterkeyswitch ON ordisconnect the 2-pinpower supply from thefuel lift pump.
Note: The fuel temperaturemust be a minimum of 38°C[100°F].
Measure the pressuredrop across thepressure-side fuel filterwhile the engine isoperating at high idleand no load.Use the Compuchek™fitting on the back ofthe fuel pump (gearpump) to measure thepressure out of the fuelpump (gear pump).This will be the highpressure reading.Use the Compuchek™fitting on the undersideof the integrated fuelsystem module (IFSM)to measure thepressure of the fuelrail. This will be the lowpressure reading.Subtract the lowreading from the highreading to obtain the
pressure drop acrossthe pressure-side fuelfilter.
Is the pressure drop acrossthe pressure-side fuel filterless than 517 kPa [75 psi]?
Is the pressure drop acrossthe pressure-side fuel filterless than 517 kPa [75 psi]?
Turn keyswitch OFFConnect the enginewiring harness to thefuel shutoff valve.
Action
Inspect the 1724 kPa [250psi] fuel pressure regulator.
Disconnect the enginewiring harness from thefueling and timingactuators.Remove the fuel linethat connects thepressure fuel filterhead on the integratedfuel system module(IFSM) to the ECMcooling plate at thecooling plate.Install a cap onto thefitting into the coolingplate to make sure noair is brought into the
fuel system.Run the fuel line into abucket and crank theengine. If there is ameasurable amount offuel coming out of theline during cranking,then fuel is bypassingthe 1724 kPa [250 psi]regulator.
Is there any amount of fuelcoming from the ECM coolingplate supply line while theengine is cranking and thefueling and timing actuatorsare disconnected from theengine harness?
Is there any amount of fuelcoming from the ECM coolingplate supply line while theengine is cranking and thefueling and timing actuatorsare disconnected from theengine harness?
YES NO
Remove and inspect the 1724kPa [250 psi] regulator fordebris that can stick theregulator open and for cut ormissing o-rings.
Inspect the 2620 kPa [380psi] fuel pressure regulator.
Disconnect the OEMdrain line connection atthe integrated fuelsystem module (IFSM).Install a short piece ofhose to run into abucket.Disconnect the wiringharness from thefueling and timingactuators.Turn the keyswitch ONand wait until the liftpump stops running.Crank the engine for15 seconds andmeasure the fuel fromthe integrated fuelsystem module (IFSM).
Is more than 237 ml [8 oz] offuel coming from the drain linewhile the engine is crankingfor 15 seconds and thefueling and timing actuatorsare disconnected from theengine harness?
Is more than 237 ml [8 oz] offuel coming from the drainline while the engine iscranking for 15 seconds andthe fueling and timingactuators are disconnectedfrom the engine harness?
YES NO
Remove and inspect the2620 kPa [380 psi]pressure regulator fordebris that can stick theregulator open and forcut or missing o-rings.Replace the regulator.
No Repair
Go to 17A Go to 16A
Guided Step 16 - Check the fuelpressure sensor for accuracy.