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Engine Controls - Basic Diagnostic Procedures: Overview Chevrolet Silverado 2500

Testing & Diagnostics ~14846 words

MODEL IDENTIFICATION

Vehicle model is identified by fifth character of Vehicle Identification Number (VIN). VIN is stamped on metal pad on top of left end of instrument panel, near windshield. See MODEL IDENTIFICATION table.

Series (1)Model
"A"2WD Aztek & Rendezvous
"B"AWD Aztek & Rendezvous
"C"2WD Avalanche, Cab & Chassis, Escalade, Sierra, Silverado, Suburban, Tahoe & Yukon XL
"G"Cutaway, Express, RV Cutaway & Savana
"K"4WD Avalanche, Cab & Chassis, Escalade, Escalade EXT, Sierra, Silverado, Suburban, Tahoe, Yukon & Yukon XL
"L"AWD Astro & Safari
"M"2WD Astro & Safari
"S"2WD Blazer, Bravada, Envoy, Jimmy Canadian, Sonoma, S10 Pickup & TrailBlazer
"T"AWD/4WD Blazer, Bravada, Envoy XL, Jimmy Canadian, Sonoma, S10 Pickup & TrailBlazer
"U"Montana, Silhouette & Venture
"Z"(2) VUE
(1) Vehicle series is fifth character of VIN. (2) AWD and 2WD models.
(1)Vehicle series is fifth character of VIN.
(2)AWD and 2WD models.

MODEL IDENTIFICATION

Test Description

The numbers below refer to the step numbers in the diagnostic procedure.

  1. 3 This step determines if ignition relay is providing listed fuses with voltage.
  2. 4 If all Cylinder Injector Circuit Status parameters display Fault, this indicates a condition with injector supply voltage circuit.
  3. 5 This step determines if fuel pump is operating electrically.
  4. 8 This step determines if Camshaft Position (CMP) sensor is functioning properly.
  1. Perform OBD system check. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in «SELF-DIAGNOSTICS - 3.4L MONTANA, SILHOUETTE & VENTURE»(ref-140805) or «SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS»(ref-140049) article. After performing OBD system check, go to next step.
  2. Using scan tool, check for DTCs. If DTCs P0101, P0123, P0230, P0336, P0341, P0601, P0602, P1626, P1630, or P1631 are set, diagnose DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in «SELF-DIAGNOSTICS - 3.4L MONTANA, SILHOUETTE & VENTURE»(ref-140805) or «SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS»(ref-140049) article. If DTCs are not set, go to next step.
  3. Turn ignition ON, with engine OFF. Probe both sides of the following fuses: IGN 1-U/H, ELEC IGN, IGN MAIN 1 and 2, and Fuel INJ. Does the test light illuminate on both sides of all the fuses listed? If yes, go to next step. If no, diagnose ignition relay or individual fuse.
  4. Monitor the Cylinder 1-6 Injector Circuit Status parameters with a scan tool. Crank the engine. Do all of the Cylinder Injector Circuit Status parameters display OK? If yes, go to next step. If no, diagnose fuel injector circuit. See FUEL INJECTOR CIRCUIT DIAGNOSIS under FUEL SYSTEMS (GASOLINE) in SYSTEM & COMPONENT TESTING - TRUCKS - EXCEPT TRACKER article.
  5. Using scan tool, command fuel pump ON. If fuel pump runs, go to next step. If fuel pump does not run, diagnose fuel pump circuit. See FUEL PUMP ELECTRICAL CIRCUIT under FUEL SYSTEMS (GASOLINE) in SYSTEM & COMPONENT TESTING - TRUCKS - EXCEPT TRACKER article.
  6. Connect Spark Tester (J-26792) to No. 1 spark plug wire. Leave other wires connected. Crank engine and check for spark. Repeat for each cylinder. If spark was present at all cylinders, go to next step. If spark was not present at all cylinders, diagnose ignition system. See ELECTRONIC IGNITION SYSTEM DIAGNOSIS under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - TRUCKS - EXCEPT TRACKER article.
  7. Turn ignition OFF. Connect all disconnected components. Install Fuel Pressure Gauge (J 34730-1A). Turn ignition ON, with engine OFF. Command the fuel pump ON with a scan tool. Is the fuel pressure 52-59 psi (358-405 kPa) when the fuel pump is operating? If yes, go to next step. If no, go to FUEL SYSTEM DIAGNOSIS under FUEL SYSTEMS (GASOLINE) in SYSTEM & COMPONENT TESTING - TRUCKS - EXCEPT TRACKER article.
  8. Disconnect fuel injector harness multi-way connector. Jumper 3 Camshaft Position (CMP) sensor circuits between fuel injector harness multi-way connectors. Probe fuel injector control circuits, PCM side of connector, with test light connected to positive battery terminal. Crank engine. Does test light blink while cranking engine? If yes, go to next step. If no, diagnose fuel injector driver circuits. See DTC P0341: CAMSHAFT POSITION SENSOR CIRCUIT PERFORMANCE under DIAGNOSTIC TESTS in «SELF-DIAGNOSTICS - 3.4L MONTANA, SILHOUETTE & VENTURE»(ref-140805) or «SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS»(ref-140049) article.
  9. Inspect for the following conditions; A collapsed air intake duct or restricted air filter element. Spark plugs that are gas fouled or coolant fouled. If the spark plugs are fouled, determine what caused the condition. Engine mechanical conditions, e.g. worn timing chain and gears, low compression, etc. Restricted exhaust system. The engine coolant temperature (ECT) sensor is NOT close to the actual engine temperature. For Montana, Silhouette and Venture, diagnose DTC P0117 or DTC P0118 under DIAGNOSTIC TESTS in «SELF-DIAGNOSTICS - 3.4L MONTANA, SILHOUETTE & VENTURE»(ref-140805) article. For Aztec and Rendezvous, diagnose DTC P0128 under DIAGNOSTIC TESTS in «SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS»(ref-140049) article. Compare the Manifold Absolute Pressure (MAP) sensor and throttle position (TP) sensor parameters to another vehicle. The parameters should be close in value. For Montana, Silhouette and Venture, diagnose DTC P0105 under DIAGNOSTIC TESTS in «SELF-DIAGNOSTICS - 3.4L MONTANA, SILHOUETTE & VENTURE»(ref-140805) article. For Aztec and Rendezvous, diagnose DTC P0121 under DIAGNOSTIC TESTS in «SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS»(ref-140049) article. Did you find and correct the condition? If yes, go to next step. If no, go to «DIAGNOSTIC AIDS»(ref-149936-S26870785552002110100000) .
  10. With a scan tool, clear any DTCs that are set. Attempt to start the engine. Does the engine start and continue to operate? If yes, go to next step. If engine does not start, go to step 2 .
  11. Allow the engine to reach operating temperature. Observe the DTC information with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, diagnose DTC. See «SELF-DIAGNOSTICS - 3.4L MONTANA, SILHOUETTE & VENTURE»(ref-140805) or «SELF-DIAGNOSTICS - 3.4L AZTEK & RENDEZVOUS»(ref-140049) article. If no, system is OK.

Description

No-Start - Engine Cranks Okay diagnostic procedure is an organized approach to identifying a condition that causes an engine not to start. No-Start - Engine Cranks Okay diagnostic procedure directs service technician to appropriate system diagnosis. No-Start - Engine Cranks Okay diagnostic procedure assumes the following

  1. Battery is completely charged.
  2. Cranking speed is acceptable.
  3. There is adequate fuel in fuel tank.

The numbers below refer to step numbers in diagnostic procedure.

  1. 8 Crankshaft Position (CKP) sensor can fail in such a way that will cause engine to crank but will not run. Engine will be able to run by using CMP sensor when CKP sensor is disconnected.
  1. Perform OBD system check. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-132531-S16910731432002012100000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 4.2L BRAVADA, ENVOY, ENVOY XL, TRAILBLAZER & TRAILBLAZER XL article. After performing OBD system check, go to next step.
  2. Turn ON the ignition, with the engine OFF. With scan tool, observe DTC information. Does scan tool display DTC P0107, P0601, P0602, P0604, P0606, P0607, P1220, P1221, P1271, P1514, P1621, P1631, P1635, P1639, P1680, P1681, or P1683? If yes, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-132531-S07878208602002012100000) in SELF-DIAGNOSTICS - 4.2L BRAVADA, ENVOY, ENVOY XL, TRAILBLAZER & TRAILBLAZER XL article. If no, go to next step.
  3. Monitor Ignition 1 Signal Voltage parameter with scan tool. Does Ignition 1 Signal Voltage parameter read battery voltage? If yes, go to next step. If no, go to step 10 .
  4. Command fuel pump ON with scan tool. Does fuel pump turn ON? If yes, go to next step. If no, go to «FUEL PUMP RELAY (ALL EXCEPT 2.2L & 3.0L VUE, 3.4L, 5.0L & 5.7L)»(ref-150429-S39786676722002111300000) under FUEL SYSTEM (GASOLINE) in SYSTEM & COMPONENT TESTING - TRUCKS - EXCEPT TRACKER article.
  5. Turn OFF the ignition. Remove an ignition coil. Install (J 26792) Spark Tester to coil boot. Attempt to start engine. Does spark tester spark? If yes, go to next step. If no, go to «ELECTRONIC IGNITION SYSTEM DIAGNOSIS (4.2L)»(ref-150429-S20449907842002120300000) under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - TRUCKS - EXCEPT TRACKER article.
  6. Turn OFF the ignition. Disconnect fuel injector harness multi-way connector. Probe a fuel injector control circuit, PCM side, with test light connected to battery voltage. Crank engine. Does test light flash when cranking engine? If yes, go to next step. If no, go to «FUEL INJECTOR CIRCUIT DIAGNOSIS (4.2L)»(ref-150429-S37645985152002120300000) under FUEL SYSTEMS (GASOLINE) in SYSTEM & COMPONENT TESTING - TRUCKS - EXCEPT TRACKER article.
  7. Turn OFF the ignition. Install (J 34730-1A) Fuel Pressure Gauge. Turn ON the ignition, with the engine OFF. Command fuel pump ON with scan tool. Is fuel pressure within 48-52 psi (334-375 kPa) while fuel pump is operating? If yes, go to next step. If no, go to «FUEL SYSTEM PRESSURE TEST (4.2L)»(ref-149936-S28337785802002112600000) under BASIC FUEL SYSTEM CHECKS (GASOLINE).
  8. Disconnect Crankshaft Position (CKP) sensor. Attempt to start engine. Does engine start and continue to run? If yes, go to step 11 . If no, go to next step.
  9. Inspect for the following: A collapsed air intake duct. A restricted air filter element. Spark plugs for being gas or coolant fouled. If spark plugs are fouled, determine what caused condition. An engine mechanical condition (worn timing chain, gears and low compression). A restricted exhaust system. Engine Coolant Temperature (ECT) sensor is not close to actual engine temperature. See «DTC P0117: ECT SENSOR CIRCUIT - LOW VOLTAGE»(ref-132531-S23800550162002012100000) or «DTC P0118: ECT SENSOR CIRCUIT - HIGH VOLTAGE»(ref-132531-S15140294882002012100000) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 4.2L BRAVADA, ENVOY, ENVOY XL, TRAILBLAZER & TRAILBLAZER XL article. Compare MAP/BARO parameters to another vehicle. Parameters should be close in value. See «DTC P0105: MAP SYSTEM PERFORMANCE»(ref-132531-S33534962272002012100000) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 4.2L BRAVADA, ENVOY, ENVOY XL, TRAILBLAZER & TRAILBLAZER XL article. TP sensor for being stuck in range. See «DTC P1221: EXCESSIVE DIFFERENCE BETWEEN THROTTLE POSITION SENSORS»(ref-132531-S14204156532002012900000) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 4.2L BRAVADA, ENVOY, ENVOY XL, TRAILBLAZER & TRAILBLAZER XL article. After repairs, go to step 12 .
  10. Repair Ignition 1 signal voltage circuit for an open or a short to ground. See «WIRING DIAGRAMS»(/chevrolet/silverado-2500/2000-2004/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams) article. Replace fuse if necessary. After repairs, go to next step.
  11. Replace CKP sensor. After repairs, go to next step.
  12. Clear DTCs with scan tool. Turn OFF the ignition for 30 seconds. Attempt to start engine. Does engine start and continue to run? If yes, go to next step. If no, go to step 2 .
  13. Allow engine to reach operating temperature. Observe DTC information with scan tool. Are there any DTCs that have not been diagnosed? If yes, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-132531-S07878208602002012100000) in SELF-DIAGNOSTICS - 4.2L BRAVADA, ENVOY, ENVOY XL, TRAILBLAZER & TRAILBLAZER XL article.

The number below refers to the step number in the diagnostic test.

  1. 5) This step determines if the fuel pump is operating electrically.
  1. Did you perform a Diagnostic System Check-Engine Controls? If yes, go to next step. If no, perform «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-137937-S42271286052002031300000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 4.3L ASTRO, BLAZER, JIMMY CANADIAN, SAFARI, SONOMA & S10 PICKUP article.
  2. Turn ON the ignition, with the engine OFF. With a scan tool, observe the DTC information. Does the scan tool display DTCs P0230, P0335, P0336, P0601, P0602, P0604, P1626, P1631 or P1683? If yes, perform appropriate diagnostic test. See appropriate SELF-DIAGNOSTICS article. If no, go to next step.
  3. Attempt to start the engine. With a scan tool, monitor the Engine Speed parameter while the engine is cranking. Does the engine speed increment? If yes, go to next step. If no, go to DISTRIBUTOR IGNITION SYSTEM DIAGNOSIS under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - TRUCKS article.
  4. Monitor the Ignition 1 Signal Voltage parameter with a scan tool. Is the Ignition 1 Signal Voltage parameter at battery voltage. If yes, go to next step. If no, go to step 10 .
  5. With a scan tool, command the fuel pump ON. Does the fuel pump turn ON? If yes, go to next step. If no, go to FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS under FUEL SYSTEMS (GASOLINE) in SYSTEM & COMPONENT TESTING - TRUCKS article.
  6. Turn OFF the ignition. Disconnect a spark plug wire. Install the J 26792 Spark Tester to the spark plug wire. Attempt to start the engine. Does the spark tester spark? If yes, go to next step. If no, go to DISTRIBUTOR IGNITION SYSTEM DIAGNOSIS under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - TRUCKS article.
  7. Turn OFF the ignition. Disconnect the injector connector. Install the J 34730-375 Injector Test Lamp to an injector connector. Attempt to start the engine. Does the test light blink while the engine is cranking. If yes, go to next step. If no, go to «DTC P0200: FUEL INJECTOR CONTROL CIRCUIT»(ref-137937-S18600309342002031300000) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 4.3L ASTRO, BLAZER, JIMMY CANADIAN, SAFARI, SONOMA & S10 PICKUP article.
  8. Turn OFF the ignition. Install the J 34730-1A Fuel Pressure Gauge. Turn ON the ignition, with the engine OFF. With a scan tool, command the fuel pump ON. Is the fuel pressure 60-66 psi (414-455 kPa)? If yes, go to next step. If no, go to FUEL SYSTEM DIAGNOSIS under FUEL SYSTEMS (GASOLINE) in SYSTEM & COMPONENT TESTING - TRUCKS article.
  9. Inspect for the following conditions: Collapsed air intake duct. Restricted air filter element. Spark plugs for being gas or coolant fouled. If the spark plugs are fouled, determine what caused the condition. Engine mechanical condition (worn timing chain, gears and low compression). Restricted exhaust system. The Engine Coolant Temperature (ECT) sensor is not close to the actual engine temperature. See «DTC P0117: ECT SENSOR CIRCUIT - LOW VOLTAGE»(ref-137937-S23368886632002031300000) or «DTC P0118: ECT SENSOR CIRCUIT - HIGH VOLTAGE»(ref-137937-S15545525912002031300000) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 4.3L ASTRO, BLAZER, JIMMY CANADIAN, SAFARI, SONOMA & S10 PICKUP article. Compare Manifold Absolute Pressure/Barometric Pressure (MAP/BARO) parameters to another vehicle. The parameters should be close in value. See «DTC P0106: MAP SYSTEM PERFORMANCE»(ref-137937-S01219711872002031300000) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 4.3L ASTRO, BLAZER, JIMMY CANADIAN, SAFARI, SONOMA & S10 PICKUP article. The Throttle Position (TP) sensor for being stuck in range. See «DTC P0121: TP SENSOR PERFORMANCE»(ref-137937-S42948407422002031300000) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 4.3L ASTRO, BLAZER, JIMMY CANADIAN, SAFARI, SONOMA & S10 PICKUP article. Did you find and correct the condition? If yes, go to step 11 . If no, fault is intermittent. See «INTERMITTENTS»(ref-149956-S33326837422002110400000) in TROUBLE SHOOTING - NO CODES - TRUCKS article.
  10. Repair the ignition 1 signal voltage circuit for an open or a short to ground. Replace the fuse, if necessary. After repair is made, go to next step.
  11. With a scan tool, clear the DTCs. Attempt to start the engine. Does the engine start and continue to operate? If yes, go to next step. If no, go to step 2 .
  12. Idle the engine. Allow the engine to reach operating temperature. With a scan tool, observe the DTC information. Are any DTCs displayed? If yes, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-137937-S42609277872002031300000) in SELF-DIAGNOSTICS - 4.3L ASTRO, BLAZER, JIMMY CANADIAN, SAFARI, SONOMA & S10 PICKUP article. If no, go to next step.
  13. With a scan tool, review the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? If yes, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-137937-S42609277872002031300000) in SELF-DIAGNOSTICS - 4.3L ASTRO, BLAZER, JIMMY CANADIAN, SAFARI, SONOMA & S10 PICKUP article. If no, system is okay.

The number below refers to the step number in the diagnostic test.

  1. 6) This step determines if the fuel pump is operating electrically.
  1. Did you perform a Diagnostic System Check-Engine Controls? If yes, go to next step. If no, perform «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-137808-S13134129342002030800000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 4.3L CHEVY EXPRESS & SAVANA article.
  2. Turn ON the ignition, with the engine OFF. With a scan tool, observe the DTC information. Does the scan tool display DTCs P0230, P0335, P0336, P0601, P0602, P0604, P1626, P1631 or P1683? If yes, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-137808-S26333189042002030800000) in SELF-DIAGNOSTICS - 4.3L CHEVY EXPRESS & SAVANA article. If no, go to next step.
  3. Observe the DTC information in Passlock®. Does the scan tool display DTC B2960? If yes, diagnose DTC. See appropriate ANTI-THEFT SYSTEMS article in ACCESSORIES & EQUIPMENT. If no, go to next step.
  4. Attempt to start the engine. With a scan tool, monitor the Engine Speed parameter while the engine is cranking. Does the engine speed increment? If yes, go to next step. If no, go to DISTRIBUTOR IGNITION SYSTEM DIAGNOSIS under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - TRUCKS article.
  5. Monitor the Ignition 1 Signal Voltage parameter with a scan tool. Is the Ignition 1 Signal Voltage parameter at battery voltage. If yes, go to next step. If no, go to step 11 .
  6. With a scan tool, command the fuel pump ON. Does the fuel pump turn ON? If yes, go to next step. If no, go to FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS under FUEL SYSTEMS (GASOLINE) in SYSTEM & COMPONENT TESTING - TRUCKS article.
  7. Turn OFF the ignition. Disconnect a spark plug wire. Install the J 26792 Spark Tester to the spark plug wire. Attempt to start the engine. Does the spark tester spark? If yes, go to next step. If no, go to DISTRIBUTOR IGNITION SYSTEM DIAGNOSIS under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - TRUCKS article.
  8. Turn OFF the ignition. Disconnect the injector connector. Install the J 34730-375 Injector Test Lamp to an injector connector. Attempt to start the engine. Does the test light blink while the engine is cranking. If yes, go to next step. If no, go to «DTC P0200: FUEL INJECTOR CONTROL CIRCUIT»(ref-137808-S39559151202002030800000) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 4.3L CHEVY EXPRESS & SAVANA article.
  9. Turn OFF the ignition. Install the J 34730-1A Fuel Pressure Gauge. Turn ON the ignition, with the engine OFF. With a scan tool, command the fuel pump ON. Is the fuel pressure 60-66 psi (414-455 kPa)? If yes, go to next step. If no, go to FUEL SYSTEM DIAGNOSIS under FUEL SYSTEMS (GASOLINE) in SYSTEM & COMPONENT TESTING - TRUCKS article.
  10. Inspect for the following conditions: Collapsed air intake duct. Restricted air filter element. Spark plugs for being gas or coolant fouled. If the spark plugs are fouled, determine what caused the condition. Engine mechanical condition (worn timing chain, gears and low compression). Restricted exhaust system. The Engine Coolant Temperature (ECT) sensor is not close to the actual engine temperature. See «DTC P0117: ECT SENSOR CIRCUIT - LOW VOLTAGE»(ref-137808-S10852978322002030800000) or «DTC P0118: ECT SENSOR CIRCUIT - HIGH VOLTAGE»(ref-137808-S25387880802002030800000) in SELF-DIAGNOSTICS - 4.3L CHEVY EXPRESS & SAVANA article. Compare Manifold Absolute Pressure/Barometric Pressure (MAP/BARO) parameters to another vehicle. The parameters should be close in value. See «DTC P0106: MAP SYSTEM PERFORMANCE»(ref-137808-S37148671312002030800000) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 4.3L CHEVY EXPRESS & SAVANA article. The throttle position (TP) sensor for being stuck in range. See «DTC P0121: TP SENSOR PERFORMANCE»(ref-137808-S35702216302002030800000) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 4.3L CHEVY EXPRESS & SAVANA article. Did you find and correct the condition? If yes, go to step 12 . If no, fault is intermittent. See «INTERMITTENTS»(ref-149956-S33326837422002110400000) in TROUBLE SHOOTING - NO CODES - TRUCKS article.
  11. Repair the ignition 1 signal voltage circuit for an open or a short to ground. Replace the fuse, if necessary. After repair is made, go to next step.
  12. With a scan tool, clear the DTCs. Attempt to start the engine. Does the engine start and continue to operate? If yes, go to next step. If no, go to step 2 .
  13. Idle the engine. Allow the engine to reach operating temperature. With a scan tool, observe the DTC information. Are any DTCs displayed? If yes, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-137808-S26333189042002030800000) in SELF-DIAGNOSTICS - 4.3L CHEVY EXPRESS & SAVANA article. If no, go to next step.
  14. With a scan tool, review the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? If yes, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-137808-S26333189042002030800000) in SELF-DIAGNOSTICS - 4.3L CHEVY EXPRESS & SAVANA article. If no, system is okay.

The number below refers to the step number in the diagnostic test.

  1. 3) This step determines if the ignition relay is providing the listed fuses with voltage.
  2. 5) This step determines if the fuel pump is operating electrically.
  1. Did you perform a Diagnostic System Check-Engine Controls? If yes, go to next step. If no, perform «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/chevrolet/silverado-2500/2000-2004/remont/testing-diagnostics/#engine-controls-self-diagnostics-43l) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 4.3L SIERRA & SILVERADO article.
  2. Turn ON the ignition, with the engine OFF. With a scan tool, observe the DTC information. Does the scan tool display DTCs P0230, P0335, P0336, P0601, P0602, P0604, P1626, P1631 or P1683? If yes, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/chevrolet/silverado-2500/2000-2004/remont/testing-diagnostics/#engine-controls-self-diagnostics-43l) in SELF-DIAGNOSTICS - 4.3L SIERRA & SILVERADO article. If no, go to next step.
  3. Turn ON the ignition, with the engine OFF. Probe both sides of fuses ECM 1, INJ A and INJ B. Does the test light illuminate on both sides of all the fuses listed? If yes, go to next step. If no, go IGNITION RELAY DIAGNOSIS under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - TRUCKS article.
  4. Attempt to start the engine. With a scan tool, monitor the Engine Speed parameter while the engine is cranking. Does the engine speed increment? If yes, go to next step. If no, go to DISTRIBUTOR IGNITION SYSTEM DIAGNOSIS under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - TRUCKS article.
  5. With a scan tool, command the fuel pump ON. Does the fuel pump turn ON? If yes, go to next step. If no, go to FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS under FUEL SYSTEMS (GASOLINE) in SYSTEM & COMPONENT TESTING - TRUCKS article.
  6. Turn OFF the ignition. Install the J 34730-1A Fuel Pressure Gauge. Turn ON the ignition, with the engine OFF. With a scan tool, command the fuel pump ON. Is the fuel pressure 60-66 psi (414-455 kPa)? If yes, go to next step. If no, go to FUEL SYSTEM DIAGNOSIS under FUEL SYSTEMS (GASOLINE) in SYSTEM & COMPONENT TESTING - TRUCKS article.
  7. Turn OFF the ignition. Disconnect a spark plug wire. Install the J 26792 Spark Tester to the spark plug wire. Attempt to start the engine. Does the spark tester spark? If yes, go to next step. If no, go to DISTRIBUTOR IGNITION SYSTEM DIAGNOSIS under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - TRUCKS article.
  8. Inspect for the following conditions: Collapsed air intake duct. Restricted air filter element. Spark plugs for being gas or coolant fouled. If the spark plugs are fouled, determine what caused the condition. Engine mechanical condition (worn timing chain, gears and low compression). Restricted exhaust system. The Engine Coolant Temperature (ECT) sensor is not close to the actual engine temperature. See «DTC P0117: ECT SENSOR CIRCUIT - LOW VOLTAGE»(/chevrolet/silverado-2500/2000-2004/remont/testing-diagnostics/#engine-controls-self-diagnostics-43l) or «DTC P0118: ECT SENSOR CIRCUIT - HIGH VOLTAGE»(/chevrolet/silverado-2500/2000-2004/remont/testing-diagnostics/#engine-controls-self-diagnostics-43l) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 4.3L SIERRA & SILVERADO article. Compare Manifold Absolute Pressure/Barometric Pressure (MAP/BARO) parameters to another vehicle. The parameters should be close in value. See «DTC P0106: MAP SYSTEM PERFORMANCE»(/chevrolet/silverado-2500/2000-2004/remont/testing-diagnostics/#engine-controls-self-diagnostics-43l) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 4.3L SIERRA & SILVERADO article. The throttle position (TP) sensor for being stuck in range. See «DTC P0121: TP SENSOR PERFORMANCE»(/chevrolet/silverado-2500/2000-2004/remont/testing-diagnostics/#engine-controls-self-diagnostics-43l) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 4.3L SIERRA & SILVERADO article. Did you find and correct the condition? If yes, go to next step. If no, fault is intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
  9. With a scan tool, clear the DTCs. Attempt to start the engine. Does the engine start and continue to operate? If yes, go to next step. If no, go to step 2 .
  10. Idle the engine. Allow the engine to reach operating temperature. With a scan tool, observe the DTC information. Are any DTCs displayed? If yes, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/chevrolet/silverado-2500/2000-2004/remont/testing-diagnostics/#engine-controls-self-diagnostics-43l) in SELF-DIAGNOSTICS - 4.3L SIERRA & SILVERADO article. If no, go to next step.
  11. With a scan tool, review the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? If yes, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/chevrolet/silverado-2500/2000-2004/remont/testing-diagnostics/#engine-controls-self-diagnostics-43l) in SELF-DIAGNOSTICS - 4.3L SIERRA & SILVERADO article. If no, system is okay.

The numbers below refer to the step numbers in the diagnostic procedure.

  1. 4 You may need to connect a battery charger to the battery for this step. If the battery state of charge is low, the scan tool may reset during the cranking test.
  2. 5 This step tests the ignition relay for proper operation. The ignition relay supplies voltage to the injectors and the ignition coils. When the ignition relay is not operating properly, a no start condition occurs. If the test light does not illuminate, this indicates the ignition relay is not suppling a voltage to the fuses.
  1. Perform «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/chevrolet/silverado-2500/2000-2004/remont/testing-diagnostics/#engine-control-system-self-diagnostics-48l-53l-60l) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 4.8L, 5.3L & 6.0L "C" & "K" SERIES TRUCKS article. After performing DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS, go to next step.
  2. Crank the engine for 15 seconds. Does the scan tool display any DTCs that failed this ignition? If yes, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/chevrolet/silverado-2500/2000-2004/remont/testing-diagnostics/#engine-control-system-self-diagnostics-48l-53l-60l) in SELF-DIAGNOSTICS - 4.8L, 5.3L & 6.0L "C" & "K" SERIES TRUCKS article. If no, go to next step.
  3. Using scan tool, check the Body Control Module (BCM) for DTCs related to the Vehicle Theft Deterrent (VTD) system. Does the scan tool display any BCM VTD DTCs? If yes, perform DIAGNOSTIC SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM in appropriate ANTI-THEFT SYSTEMS article in ACCESSORIES & EQUIPMENT. If no, go to next step.
  4. Using scan tool, monitor the engine speed while cranking the engine. Is engine RPM indicated on the scan tool? If yes, go to next step. If no, see ELECTRONIC IGNITION SYSTEM DIAGNOSIS under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - TRUCKS - EXCEPT TRACKER article.
  5. Turn ignition switch to ON position. Using a test light connected to ground, probe both sides of fuses INJR A, INJR B and ECM I, located in the underhood electrical center. Does the test light illuminate on both sides of all 3 fuses? If yes, go to next step. If no, see IGNITION RELAY DIAGNOSIS under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - TRUCKS - EXCEPT TRACKER article.
  6. Using the scan tool, monitor the Engine Coolant Temperature (ECT) parameter. Is the ECT on the scan tool close to the actual engine temperature? If yes, go to next step. If no, see «DTC P0118: ECT SENSOR CIRCUIT - HIGH VOLTAGE»(/chevrolet/silverado-2500/2000-2004/remont/testing-diagnostics/#engine-control-system-self-diagnostics-48l-53l-60l) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 4.8L, 5.3L & 6.0L "C" & "K" SERIES TRUCKS article.
  7. Using the scan tool, enable the fuel pump. Does the fuel pump operate? If yes, go to next step. If no, see FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS under FUEL SYSTEMS (GASOLINE) in SYSTEM & COMPONENT TESTING - TRUCKS - EXCEPT TRACKER article.
  8. Turn ignition switch to OFF position. Release fuel pressure and install a fuel pressure gauge. See «FUEL SYSTEM PRESSURE RELEASE (4.8L, 5.3L, 6.0L & 8.1L)»(ref-149936-S30080408262002110100000) under BASIC FUEL SYSTEM CHECKS (GASOLINE). The fuel pump operates for about 2 seconds when the ignition switch is turned to the ON position. The fuel pressure must be observed when the fuel pump is operating. Turn ignition switch to ON position. Observe the fuel pressure while the fuel pump is operating. Is the fuel pressure 55-62 psi (379-427 kPa)? If yes, go to next step. If no, diagnose fuel system. See FUEL SYSTEM PRESSURE TEST under BASIC FUEL SYSTEM CHECKS (GASOLINE).
  9. Perform the following checks: Check air duct between MAF sensor and throttle body for air leaks. Using scan tool, ensure throttle angle is at zero percent with throttle closed. If throttle angle is not as specified, diagnose using appropriate diagnostic procedure for TP sensor DTCs. See «DTC P0121: TP SENSOR PERFORMANCE»(/chevrolet/silverado-2500/2000-2004/remont/testing-diagnostics/#engine-control-system-self-diagnostics-48l-53l-60l) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 4.8L, 5.3L & 6.0L "C" & "K" SERIES TRUCKS article. A malfunctioning Mass Airflow (MAF) sensor may cause a no start or a stall after a start. If you suspect this, disconnect the MAF sensor. The PCM will default to the speed density in order to calculate the engine load and the intake air flow. If disconnecting the MAF sensor corrects the condition and the connections are OK, replace the MAF sensor. See MASS AIRFLOW SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - SIERRA & SILVERADO article. Check for fouled spark plugs. If fouled, determine cause and repair as necessary. Check for possible engine mechanical failure causing a no-start condition, such as timing chain or low compression. Compare the MAP/BARO parameters to another vehicle. The parameter values should be close to each other. Did you find and correct the condition? If yes, go to next step. If no, see «HARD START»(ref-149956-S05654487592002110400000) under SYMPTOMS (GASOLINE) in TROUBLE SHOOTING - NO CODES - TRUCKS article.
  10. Using scan tool, clear DTCs. Attempt to start engine. Does engine start and continue to run? If yes, go to next step. If no, go to step 2 .
  11. Start and idle engine until normal operating temperature is reached. Using scan tool, check for DTCs. If any DTCs are set, diagnose DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/chevrolet/silverado-2500/2000-2004/remont/testing-diagnostics/#engine-control-system-self-diagnostics-48l-53l-60l) in SELF-DIAGNOSTICS - 4.8L, 5.3L & 6.0L "C" & "K" SERIES TRUCKS article. If no DTCs are set, go to next step.
  12. Using scan tool, select CAPTURE INFO and REVIEW INFO functions. If any DTCs are set that have not been diagnosed, diagnose DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/chevrolet/silverado-2500/2000-2004/remont/testing-diagnostics/#engine-control-system-self-diagnostics-48l-53l-60l) in SELF-DIAGNOSTICS - 4.8L, 5.3L & 6.0L "C" & "K" SERIES TRUCKS article. If no DTCs are set, system is okay.

The number below refers to the step number in the diagnostic test.

  1. 2) If the engine starts, the problem could be intermittent. Basic engine mechanical problems, the Vehicle Theft Deterrent (VTD) system (if equipped), and poor connections could cause a no-start condition.
  2. 3) This step will determine if the cause of the no start or start and stall is related to the VTD.
  3. 4) If the signal is over 2.5 volts, the engine may be in the clear flood mode which will cause starting problems.
  4. 5) If the engine coolant sensor is below -22°F (-30°C), the PCM provides fuel for this extremely cold temperature which will severely flood the engine.
  5. 6) Voltage at the spark plug is checked using the spark plug tester tool. No spark indicates a basic ignition problem.
  6. 7) This test will determine if there is fuel pressure at the fuel injection unit and holding steady.
  7. 8) Use the injector test light in order to test the injector circuits. A blinking lamp indicates that the PCM is controlling the injector.

Note. Before clearing the DTCs, use the scan tool Capture Info. to save the Freeze Frame and the Failure Records for reference. The control modules data is deleted once the Clear Info function is used.

  1. Did you perform a Diagnostic System Check-Engine Controls? If yes, go to next step. If no, perform «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138116-S40610776842002032000000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 5.0L & 5.7L CHEVY EXPRESS & SAVANA article.
  2. Attempt to start the engine. Does the engine start and continue to run? If yes, fault is intermittent. See «INTERMITTENTS»(ref-149956-S33326837422002110400000) in TROUBLE SHOOTING - NO CODES - TRUCKS article. If no, go to next step.
  3. Install a scan tool. Monitor the VTD fuel disables parameter. Crank the engine. Does the VTD fuel disables parameter display active while you crank the engine? If yes, perform THEFT DETERRENT SYSTEM DIAGNOSTIC SYSTEM CHECK. See appropriate ANTI-THEFT SYSTEMS article in ACCESSORIES & EQUIPMENT.
  4. Monitor the Throttle Position (TP) sensor on the scan tool. With the throttle closed, is the TP sensor more than 2.5 volts? If yes, go to «DTC P0121: TP SENSOR PERFORMANCE»(ref-138116-S07326966892002032000000) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 5.0L & 5.7L CHEVY EXPRESS & SAVANA article. If no, go to next step.
  5. Monitor the ECT sensor on the scan tool. Is the ECT sensor below -22°F (-30°C)? If yes, go to «DTC P0118: ECT SENSOR CIRCUIT - HIGH VOLTAGE»(ref-138116-S13159537662002032000000) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 5.0L & 5.7L CHEVY EXPRESS & SAVANA article. If no, go to next step.
  6. Check for spark at two spark plug wires using the J-26792 Spark Tester. Is spark present at both spark plug wires? If yes, go to next step. If no, go to ELECTRONIC IGNITION SYSTEM DIAGNOSIS under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - TRUCKS article.
  7. Reconnect the spark plug wires. Turn OFF the ignition. Connect the J 34730-1A Fuel Pressure Gauge. Turn ON the ignition, with the engine OFF. Is the fuel pressure 55-60 psi (379-413 kPa)? If yes, go to next step. If no, go to FUEL SYSTEM DIAGNOSIS under FUEL SYSTEMS (GASOLINE) in SYSTEM & COMPONENT TESTING - TRUCKS article.
  8. Disconnect the injector connector at the intake manifold. Install the J 34730-375 Injector Test Lamp into each injector circuit one at a time. Crank the engine with the injector test light in each circuit. Does the injector test light flash for each injector circuit? If yes, go to Diagnostic Aids. See «DIAGNOSTIC AIDS»(ref-149936-S00466976912002111400000) . If no, go to «DTC P0200: FUEL INJECTOR CONTROL CIRCUIT»(ref-138116-S06454471742002032000000) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 5.0L & 5.7L CHEVY EXPRESS & SAVANA article.

The numbers below refer to the step numbers in the diagnostic procedure.

  1. 6 This step checks for proper cranking speed. See «DIAGNOSTIC AIDS»(ref-149936-S39508763402002111400000) .
  2. 8 This step will check ground wire on injection pump. Wire is located on top of pump.
  3. 12 This step will determine if injection pump or wiring is at fault.
  4. 13 This step will determine if fuel injection control voltage is present by probing at Black/Gray 4-pin connector jumper harness instead of at 6-pin pump connector.
  1. Perform OBD system check. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-139779-S23178353562002050900000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 6.5L CAB & CHASSIS, CHEVY EXPRESS & SAVANA article. After performing OBD system check, go to next step.
  2. Check battery condition. If batteries are okay, go to next step. If condition of batteries is not okay, go to step 22 .
  3. Check fuel level in tank. If fuel level is okay, go to next step. If fuel level is not okay, go to step 22 .
  4. Check quality of fuel. If fuel quality is okay, go to next step. If fuel quality is not okay, go to step 22 .
  5. Check glow plug system operation. Go to GLOW PLUG SYSTEM DIAGNOSIS under FUEL SYSTEM (DIESEL) in SYSTEM & COMPONENT TESTING - TRUCKS - EXCEPT TRACKER article. If glow plug operation is okay, go to next step. If glow plug operation is not okay, go to step 22 .
  6. Check for proper engine cranking speed. See «DIAGNOSTIC AIDS»(ref-149936-S39508763402002111400000) . If engine cranking speed is okay, go to next step. If engine cranking speed is not okay, go to step 22 .
  7. Check fuel supply system. Go to FUEL SYSTEM DIAGNOSIS (6.5L) under FUEL SYSTEM (DIESEL) in SYSTEM & COMPONENT TESTING - TRUCKS - EXCEPT TRACKER article. If fuel system is okay, go to next step. If fuel system is not okay, go to step 22 .
  8. Check injection pump ground wire located on top of injection pump. If ground wire is okay, go to next step. If ground wire is not okay, go to step 22 .
  9. Install scan tool. Using scan tool, check for any data. If data is displayed, go to next step. If data is not displayed, see SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SYSTEM TESTS in APPROPRIATE BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
  10. Using scan tool, monitor VTD Fuel Disabled parameter on Powertrain Engine Data 1 list. Crank engine. If VTD Fuel Disabled parameter displays ACTIVE while engine is cranked, diagnose VTD system. See appropriate ANTI-THEFT SYSTEMS article in ACCESSORIES & EQUIPMENT. If VTD Fuel Disabled parameter does not display ACTIVE, go to next step.
  11. Loosen injector line at injector. Crank engine and check for fuel. Repeat procedure for all injectors. If fuel flows from each injection line, injection system is okay. If fuel does not flow from each injection line, go to next step.
  12. Disconnect optical/fuel temperature sensor. Attempt to start engine. If engine starts, go to step 16 . If engine does not start, go to next step.
  13. Reconnect optical/fuel temperature sensor. Disconnect fuel solenoid driver at fuel injection pump 4-pin connector. Using DVOM, measure voltage between ground and fuel injector control circuit at harness connector while cranking engine. See «WIRING DIAGRAMS»(/chevrolet/silverado-2500/2000-2004/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams) article. If voltage is 1.2 volts or more, go to next step. If voltage is less than 1.2 volts, go to step 17 .
  14. With fuel solenoid driver 4-pin connector still disconnected, probe solenoid closure ground circuit at harness connector with test light connected to battery voltage. If test light illuminates, go to next step. If test light does not illuminate, go to step 18 .
  15. Turn ignition on. Ensure fuel solenoid driver 4-pin connector is still disconnected. Using test light connected to ground, probe ignition feed circuit at fuel solenoid harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 20 .
  16. Replace fuel injection pump. After repairs, go to step 24 .
  17. Check for open or short to ground in fuel injection control circuit between fuel solenoid driver and PCM. Repair as necessary. After repairs, go to step 21 . If circuit is okay, go to step 19 .
  18. Check closure signal ground circuit for open between fuel solenoid driver and PCM. Repair as necessary. After repairs, go to step 21 . If circuit is okay, go to next step.
  19. Check for poor connections at fuel solenoid driver and PCM harness connectors. Repair as necessary. After repairs, go to step 21 . If connections are okay, go to step 23 .
  20. Repair open in Ignition 1 voltage circuit. After repairs, go to step 24 .
  21. Repair circuit as necessary. After repairs, go to step 24 .
  22. Repair as necessary. After repairs, go to step 24 .
  23. Replace PCM. Perform PCM relearn procedures. See «PROGRAMMING»(ref-139779-S22575193592002050900000) in SELF-DIAGNOSTICS - 6.5L CAB & CHASSIS, CHEVY EXPRESS & SAVANA article. After repairs, go to next step.
  24. Using scan tool, select DTC, Clear Info. function. Attempt to start engine. If engine starts and continues to run, go to next step. If engine does not start, or starts and stalls, go to step 2 .
  25. Using scan tool, select Capture Info, Review Info function. If any other DTCs are set that have not been diagnosed, diagnose DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-139779-S39258880492002050900000) in SELF-DIAGNOSTICS - 6.5L CAB & CHASSIS, CHEVY EXPRESS & SAVANA article. If DTCs are not set, system is okay.

The numbers below refer to the step numbers in the diagnostic procedure.

  1. 4 This step tests for Ignition 1 voltage supply to engine control module (ECM).
  2. 6 This step tests 12-volt reference circuit to CKP sensor and CMP sensor. 12-volt reference circuit for CKP sensor and CMP sensor is connected internally within ECM. If 12-volt reference circuit is shorted to ground, engine will not start and no engine speed will be indicated on scan tool.
  3. 7 If there is high resistance in signal or low reference circuits of CKP sensor, Engine Speed parameter on scan tool will display a value more than zero. It will not be an accurate measure of engine speed, and can cause an NO-START - ENGINE CRANKS OKAY condition.
  4. 8 If there is fuel in engine oil, fuel may be leaking from fuel injector or fuel injection pump into crankcase.
  5. 9 If fuel system will not even briefly prime to 10 psi and will not start, check valve in fuel filter/heater element housing is stuck open.
  6. 10 This step determines if fuel system is bleeding down causing a no-start. Fuel pressure will slowly drop to zero psi, but should still be above 8 psi for 10 seconds after pressurizing fuel system.
  7. 12 This step determines if problem is a stuck open or broken fuel injector. If fuel vapors come out of any glow plug holes, excessive fuel is being sent into a cylinder, and not being distributed to all fuel injectors.
  8. 13 The engine will not run without an actual fuel rail pressure more than 1450 psi (10 MPa).
  9. 15 If no-start condition takes place in cold operating temperatures, 35-40°F (2-4°C) or colder, a glow plug system failure may cause no-start condition.
  10. 17 In some cases, no compression, possibly with excessive fuel, in a single cylinder can cause a no-start.
  1. Perform OBD system check. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-138411-S24056483272002041200000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 6.6L SIERRA & SILVERADO article. After performing diagnostic system check, go to next step.
  2. Turn ignition on, with engine off. Check for DTCs. If DTC P0088, P0089, P0090, P0335, P0336, P0340, P0370, P0374, P0380, P0601, P0602, P0603, P0604, P0611, P0612, P1621, P1626, P1631, P1683, or U1800 is set, perform appropriate diagnostic procedure for DTC set. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) in SELF-DIAGNOSTICS - 6.6L SIERRA & SILVERADO article. If no DTCs are set, go to next step.
  3. If customer's concern is with a fuel smell or fuel leak, go to «FUEL LEAKS INSIDE OF ENGINE (6.6L)»(ref-150429-S40389620302002111300000) or «FUEL LEAKS OUTSIDE OF ENGINE (6.6L)»(ref-150429-S11276392482002111300000) under FUEL SYSTEM (DIESEL) in SYSTEM & COMPONENT TESTING - TRUCKS - EXCEPT TRACKER article. If a fuel smell or fuel leak concern is not present, go to next step.
  4. Turn ignition on. Using scan tool, observe Actual Fuel Rail Pressure parameter. If pressure is 159-203 psi (1100-1400 kPa), go to next step. If pressure is not as specified, go to step 18 .
  5. Using scan tool, observe Ignition 1 signal parameter. If Ignition 1 signal parameter indicates battery voltage, go to next step. If Ignition 1 signal parameter does not indicate battery voltage, go to step 24 .
  6. Attempt to start engine. Using scan tool, observe Engine Speed parameter while cranking engine. If Engine Speed parameter is more than zero RPM, go to next step. If Engine Speed parameter is not more than zero RPM, go to step 19 .
  7. Test CKP sensor signal and low reference circuits for high resistance. See «WIRING DIAGRAMS»(/chevrolet/silverado-2500/2000-2004/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams) article. After repairs, go to step 34 . If CKP sensor signal and low reference circuits are okay, go to next step.
  8. Check for excessive fuel in engine oil, contaminated fuel and check fuel specific gravity. After repairs, go to step 34 . If engine oil, fuel and fuel specific gravity are okay, go to next step.
  9. Install vacuum gauge to fuel system service port on right front side of engine. Attempt to hand prime fuel manager 30 times or until fuel pressure is 8 psi (55 kPa). If fuel system is able to be primed to 8 psi (55 kPa), go to next step. If fuel system is not able to be primed to 8 psi (55 kPa), go to step 31 .
  10. If system pressure is maintained at more than 2.0 psi (13.8 kPa) for more than 2 minutes, go to next step. If system is not able to maintain more than 2.0 psi (13.8 kPa) for more than 2 minutes, go to step 14 .
  11. Check engine compression. For compression specifications, see «SERVICE & ADJUSTMENT SPECIFICATIONS - TRUCKS»(ref-138752) article. Repair engine as necessary. After repairs, go to step 34 . If engine compression is within specification, go to next step.
  12. If any cylinders emitted fuel vapor during engine compression test, go to step 28 . If no fuel vapor was emitted from cylinders during engine compression test, go to next step.
  13. Crank engine for 15 seconds. Using scan tool, observe Actual Fuel Rail Pressure parameter. If Actual Fuel Rail Pressure parameter is more than 1450 psi (10 MPa), go to step 15 . If Actual Fuel Rail Pressure parameter is 1450 psi (10 MPa) or less, go to next step.
  14. Reprime fuel manager to 10 psi. Attempt to start engine while prime is still above 8 psi (55 kPa). If engine now starts, go to «FUEL SYSTEM DIAGNOSIS - PICKUP (6.6L)»(ref-150429-S00516522002002111300000) or «FUEL SYSTEM DIAGNOSIS - CAB & CHASSIS (6.6L)»(ref-150429-S03155971582002111300000) under FUEL SYSTEM (DIESEL) in SYSTEM & COMPONENT TESTING - TRUCKS - EXCEPT TRACKER article. If engine does not start, go to «FUEL SYSTEM DIAGNOSIS - HIGH PRESSURE SIDE»(ref-150429-S06204432152002111300000) under FUEL SYSTEM (DIESEL) in SYSTEM & COMPONENT TESTING - TRUCKS - EXCEPT TRACKER article.
  15. Using scan tool, observe Glow Plug System Type parameter. If Glow Plug System Type indicates Federal, go to next step. If Glow Plug System Type does not indicate Federal, go to step 17 .
  16. Turn ignition off. Connect a test light to a glow plug harness connector on one side of engine. Turn ignition on, with engine off. If test light illuminates and then goes off, go to next step. If test light does not illuminate and then go off, go to «GLOW PLUG SYSTEM DIAGNOSIS»(ref-150429-S03033516202002111300000) under FUEL SYSTEM (DIESEL) in SYSTEM & COMPONENT TESTING - TRUCKS - EXCEPT TRACKER article.
  17. Check for the following conditions: Plugged air filter. Collapsed air intake duct. Inoperative fuel heater. If customer's concern is that engine will not start when ambient temperatures are less than 35-40°F (2-4°C), go to «FUEL HEATER INOPERATIVE DIAGNOSIS (6.6L)»(ref-150429-S20356813772002111300000) under FUEL SYSTEM (DIESEL) in SYSTEM & COMPONENT TESTING - TRUCKS - EXCEPT TRACKER article. Restricted exhaust system. Repair as necessary. After repairs, go to step 34 . If no repairs are necessary, go to «DIAGNOSTIC AIDS»(ref-149936-S15231219902002111300000) .
  18. Disconnect fuel rail pressure sensor. Using scan tool, observe Actual Fuel Rail Pressure parameter on scan tool. If Actual Fuel Rail Pressure parameter is more than 25,381 psi (175 MPa), go to step 23 . If Actual Fuel Rail Pressure parameter is 25,381 psi (175 MPa) or less, go to step 22 .
  19. Turn ignition off. Disconnect Crankshaft Position (CKP) sensor. Turn ignition on, with engine off. Using a DVOM connected to ground, probe 12-volt reference circuit at CKP sensor. If voltage is more than 10 volts, go to step 29 . If voltage is 10 volts or less, go to next step.
  20. Turn ignition off. Disconnect Camshaft Position (CMP) sensor. Turn ignition on, with engine off. Using a DVOM connected to ground, probe 12-volt reference circuit of CMP sensor. If voltage is more than 10 volts, go to step 30 . If voltage is 10 volts or less, go to next step.
  21. Check 12-volt reference circuit to CKP sensor and CMP sensor for a short to ground. See «WIRING DIAGRAMS»(/chevrolet/silverado-2500/2000-2004/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams) article. Repair as necessary. After repairs, go to step 34 . If no repairs are necessary, go to step 33 .
  22. Check fuel rail pressure sensor signal circuit for a short to ground. See «WIRING DIAGRAMS»(/chevrolet/silverado-2500/2000-2004/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams) article. Repair as necessary. After repairs, go to step 34 . If no repairs are necessary, go to step 33 .
  23. Check fuel rail pressure sensor circuits for high resistance. See «WIRING DIAGRAMS»(/chevrolet/silverado-2500/2000-2004/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams) article. Repair as necessary. After repairs, go to step 34 . If no repairs are necessary, go to step 25 .
  24. Check Ignition 1 voltage circuit of ECM for a short to ground, high resistance or an open. See «WIRING DIAGRAMS»(/chevrolet/silverado-2500/2000-2004/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams) article. Repair as necessary. After repairs, go to step 34 . If no repairs are necessary, go to step 26 .
  25. Check for an intermittent or for a poor connection at fuel rail pressure sensor. Repair as necessary. After repairs, go to step 34 . If no repairs are necessary, go to step 32 .
  26. Clean and tighten ECM shared ground. See «WIRING DIAGRAMS»(/chevrolet/silverado-2500/2000-2004/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams) article. Repair as necessary. After repairs, attempt to start engine. If engine starts, go to step 34 . If engine does not start, go to next step.
  27. Check for an intermittent and for a poor connection at ECM. Repair as necessary. After repairs, go to step 34 . If no repairs are necessary, go to step 33
  28. Replace fuel injectors on affected cylinders. After repairs, go to step 34 .
  29. Replace CKP sensor. After repairs, go to step 34 .
  30. Replace CMP sensor. After repairs, go to step 34 .
  31. Replace fuel filter/heater element housing. After repairs, go to step 34 .
  32. Replace fuel rail pressure sensor. After repairs, go to step 34 .
  33. Replace ECM. Perform ECM relearn procedures. See «PROGRAMMING»(ref-138411-S27281177062002041200000) in SELF-DIAGNOSTICS - 6.6L SIERRA & SILVERADO article. After repairs, go to next step.
  34. Clear DTCs. Attempt to start engine. If engine starts and continues to run, go to next step. If engine does not start, repeat step 2
  35. Allow engine to idle until normal operating temperature is reached. Check for DTCs. If any DTCs are set, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-138411-S02438938112002041200000) in SELF-DIAGNOSTICS - 6.6L SIERRA & SILVERADO article. If no DTCs are set, system is okay.

The numbers below refer to the step numbers in the diagnostic procedure.

  1. 3 This step determines if ignition relay is providing ECM 1, ETC, INJ A and INJ B fuses with voltage.
  2. 5 This step determines if fuel pump is operating electrically.
  1. Perform OBD system check. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(/chevrolet/silverado-2500/2000-2004/remont/testing-diagnostics/#engine-control-system-self-diagnostics-81l-c-g-k-series-trucks) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 8.1L "C", "G" & "K" SERIES TRUCKS article. After performing diagnostic system check, go to next step.
  2. Turn ignition on, with engine OFF. Check for DTCs. If DTC P0230, P0335, P0336, P0601, P0602, P0604, P0606, P1626, P1631 or P1683 is set, perform appropriate diagnostic procedure for DTC set. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/chevrolet/silverado-2500/2000-2004/remont/testing-diagnostics/#engine-control-system-self-diagnostics-81l-c-g-k-series-trucks) in SELF-DIAGNOSTICS - 8.1L "C", "G" & "K" SERIES TRUCKS article. If no DTCs are set, go to next step.
  3. Turn ignition on, with engine OFF. Using test light connected to ground, probe both sides of ECM 1, ETC, INJ A and INJ B fuses. If test light illuminates on both sides of all fuses, go to next step. If test light does not illuminate on both sides of all fuses, go to «IGNITION RELAY DIAGNOSIS (8.1L)»(ref-150429-S22140985882002111300000) under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - TRUCKS - EXCEPT TRACKER article.
  4. Turn ignition off. Disconnect a spark plug wire. Install Spark Tester (J 26792) to spark plug wire. Attempt to start engine. If spark tester indicates a good spark, go to next step. If spark tester does not indicate a good spark, go to «ELECTRONIC IGNITION SYSTEM DIAGNOSIS (8.1L)»(ref-150429-S31697474672002111300000) under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - TRUCKS - EXCEPT TRACKER article.
  5. Using scan tool, command fuel pump ON. If fuel pump operates, go to next step. If fuel pump does not operate, go to FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS under FUEL SYSTEMS (GASOLINE) in SYSTEM & COMPONENT TESTING - TRUCKS - EXCEPT TRACKER article.
  6. Turn ignition off. Install fuel pressure gauge. Turn ignition on, with engine off. Using scan tool, command fuel pump ON. If fuel pressure is 55-62 psi (384-425 kPa) while fuel pump is operating, go to next step. If fuel pressure is not as specified, go to «FUEL SYSTEM PRESSURE TEST (4.8L, 5.3L, 6.0L & 8.1L)»(ref-149936-S35718292332002110100000) under BASIC FUEL SYSTEM CHECKS (GASOLINE).
  7. Turn ignition off. Disconnect an injector connector. Install Injector Test Light (J 34730-405) to injector connector. Attempt to start engine. If test light blinks while engine is cranking, go to next step. If test light does not blink while cranking, go to «DTC P0200: FUEL INJECTOR CONTROL CIRCUIT»(/chevrolet/silverado-2500/2000-2004/remont/testing-diagnostics/#engine-control-system-self-diagnostics-81l-c-g-k-series-trucks) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 8.1L "C", "G" & "K" SERIES TRUCKS article.
  8. Check for the following conditions: Collapsed air intake duct. Restricted air filter element. Spark plugs for being gas or coolant fouled. If spark plugs are fouled, determine what caused condition. Engine mechanical condition, worn timing chain and gears, low compression, etc. Restricted exhaust system. ECT sensor is NOT close to actual engine temperature. Compare MAP/barometric pressure (BARO) parameters to another vehicle. The parameters should be close in value. After repairs, go to next step. If no problems are found, go to «DIAGNOSTIC AIDS»(ref-149936-S03072657692002111300000) .
  9. Clear DTCs. Attempt to start engine. If engine starts and continues to run, go to next step. If engine does not run, repeat step 2 .
  10. Allow engine to idle and reach operating temperature. Check for DTCs. If any DTCs are set, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/chevrolet/silverado-2500/2000-2004/remont/testing-diagnostics/#engine-control-system-self-diagnostics-81l-c-g-k-series-trucks) in SELF-DIAGNOSTICS - 8.1L "C", "G" & "K" SERIES TRUCKS article. If no DTCs are set, go to next step.
  11. Using scan tool, review stored information, Capture Info. If scan tool displays any DTCs that have not been diagnosed, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/chevrolet/silverado-2500/2000-2004/remont/testing-diagnostics/#engine-control-system-self-diagnostics-81l-c-g-k-series-trucks) in SELF-DIAGNOSTICS - 8.1L "C", "G" & "K" SERIES TRUCKS article. If no DTCs are set, system is okay.

System Description

When you turn ON the ignition switch, control module enables fuel pump, relay which powers fuel pump ON. Fuel pump remains ON as long as engine is cranking or running and control module receives ignition reference pulses. If there are no ignition reference pulses, control module shuts fuel pump OFF within 2 seconds after ignition was switched to ON position or if engine stops. Fuel tank stores fuel supply. Electric fuel pump supplies fuel through an in-line fuel filter to fuel injection system. Pump provides fuel at a higher rate of flow than is needed by fuel injection system. Fuel pressure regulator maintains correct fuel pressure to fuel injection system. A separate pipe returns unused fuel to fuel tank.

The numbers below refer to step numbers in diagnostic procedure.

  1. 2 This step verifies fuel pump is operating.
  2. 4 This step tests for an internal fuel leak. If fuel pressure decreases during this test, then an internal loss of pressure is indicated.
  3. 7 This step inspects fuel pressure regulator for a fuel leak from atmospheric vent. If fuel leaks from fuel pressure regulator while fuel pump is commanded ON, replace fuel pressure regulator.
  4. 8 This step tests for a loss of fuel pressure between shut-off adapter on fuel feed pipe and fuel pump.
  5. 9 This step tests for a leaking fuel injector or fuel pressure regulator. If fuel pressure remains constant during this test, fuel injectors are not leaking fuel.
  6. 12 This step tests for a restricted fuel return pipe. If fuel pressure is within specified values, a restriction in fuel return pipe is indicated.
  7. 14 This step determines if fuel pressure regulator, or fuel pump, is cause of low fuel pressure. If pressure rises above specified value, fuel pump is okay.
  8. 16 This step verifies that a circuit condition is not cause of a fuel pressure concern. Inspect all fuel pump electrical circuits thoroughly.
  1. Did you perform a Diagnostic System Check-Engine Controls? If yes, go to next step. If no, perform «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-132531-S16910731432002012100000) under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 4.2L BRAVADA, ENVOY, ENVOY XL, TRAILBLAZER & TRAILBLAZER XL article.
  2. Turn ON the ignition, with the engine OFF. Command fuel pump ON with scan tool. Does fuel pump operate? If yes, go to next step. If no, go to «FUEL PUMP RELAY (ALL EXCEPT 2.2L & 3.0L VUE, 3.4L, 5.0L & 5.7L)»(ref-150429-S39786676722002111300000) under FUEL SYSTEMS (GASOLINE) in SYSTEM & COMPONENT TESTING - TRUCKS - EXCEPT TRACKER article.
  3. Turn OFF the ignition. Turn OFF all accessories. Install fuel pressure gauge. Turn ON the ignition, with the engine OFF. Command fuel pump ON with scan tool. Observe fuel pressure gauge, with fuel pump commanded ON. Is fuel pressure within 48-54 psi (334-375 kPa)? If yes, go to next step. If no, go to step 10 .
  4. Monitor fuel pressure gauge for one minute. Does fuel pressure decrease by more than 5 psi (34 kPa)? If yes, go to step 7 . If no, go to next step.
  5. Relieve fuel pressure to 10 psi (69 kPa). Monitor fuel pressure gauge for 5 minutes. Does fuel pressure decrease by more than 2 psi (14 kPa)? If yes, go to step 21 . If no, go to next step.
  6. Operate vehicle within conditions of customer's concern. Monitor fuel related parameters with scan tool. Do scan tool parameters indicate a lean condition? If yes, go to step 15 . If no, go to «SYMPTOM DIAGNOSIS»(ref-149956-S03463841772002110400000) under SYMPTOMS (GASOLINE) in TROUBLE SHOOTING - NO CODES - TRUCKS article.
  7. Turn OFF the ignition. Remove vent hose from fuel pressure regulator. Turn ON the ignition, with the engine OFF. Command fuel pump ON with scan tool. Inspect for a fuel leak from fuel pressure regulator atmospheric vent. Is fuel pressure regulator leaking fuel? If yes, go to step 20 . If no, go to next step.
  8. Turn OFF the ignition. Relieve fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-149936-S30080408262002110100000) . Disconnect fuel feed hose and fuel return hose from fuel rail pipes. See «FUEL LINE DISCONNECT FITTINGS»(ref-149799-S04525470992002102500000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - BRAVADA, ENVOY, ENVOY XL & TRAILBLAZER. Install (J 37287) Fuel Line Shut-Off Adapters between fuel hoses and fuel rail pipes. Open valves on fuel pipe shut-off adapters. Turn ON the ignition, with the engine OFF. Command fuel pump ON with scan tool. Bleed air from fuel pressure gauge. Command fuel pump ON and then OFF with scan tool. Close fuel feed pipe shut-off valve. Monitor fuel pressure gauge for one minute. Does fuel pressure remain constant? If yes, go to next step. If no, go to step 17 .
  9. Turn OFF the ignition. Open fuel feed pipe shut-off valve. Turn ON the ignition, with the engine OFF. Command fuel pump ON and then OFF with scan tool. Close fuel return pipe shut-off valve. Monitor fuel pressure gauge for one minute. Does fuel pressure remain constant? If yes, go to step 20 . If no, go to step 18 .
  10. Is fuel pressure more than 54 psi (375 kPa)? If yes, go to step 12 . If no, go to next step.
  11. Is fuel pressure more than 0 psi (0 kPa)? If yes, go to step 14 . If no, go to step 15 .
  12. Turn OFF the ignition. Relieve fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-149936-S30080408262002110100000) . Disconnect fuel feed hose and fuel return hose from fuel rail pipes. See «FUEL LINE DISCONNECT FITTINGS»(ref-149799-S04525470992002102500000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - BRAVADA, ENVOY, ENVOY XL & TRAILBLAZER. Attach a length of flexible fuel hose to fuel rail return pipe. Place open end of flexible fuel hose into an approved gasoline container. Turn ON the ignition, with the engine OFF. Monitor fuel pressure gauge while fuel pump is operating. Is fuel pressure within 48-54 psi (334-375 kPa)? If yes, go to step 19 . If no, go to next step.
  13. Inspect fuel rail return pipe and fuel rail outlet passage for a restriction. Did you find and correct the condition? If yes, go to step 22 . If no, go to step 20 .
  14. Turn OFF the ignition. Relieve fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-149936-S30080408262002110100000) . Disconnect fuel feed hose and fuel return hose from fuel rail pipes. See «FUEL LINE DISCONNECT FITTINGS»(ref-149799-S04525470992002102500000) under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - BRAVADA, ENVOY, ENVOY XL & TRAILBLAZER. Install (J 37287) between fuel return pipe and fuel rail. Open valve in fuel pipe shut-off adapter. CAUTION: DO NOT allow fuel pressure to exceed 75 psi (517 kPa). Excessive pressure may damage fuel system. Turn ON the ignition, with the engine OFF. Command fuel pump ON with scan tool. Bleed air from fuel system. Monitor fuel pressure gauge. Slowly close valve in fuel return pipe shut-off adapter. Command fuel pump ON with scan tool. Does fuel pressure rise above 54 psi (375 kPa)? if yes, go to step 20 . If no, go to next step.
  15. Inspect fuel filter and fuel feed pipe for a restriction. Did you find and correct the condition? If yes, go to step 22 . If no, go to next step.
  16. Inspect harness connectors and ground circuits of fuel pump for poor connections. Did you find and correct the condition? If yes, go to step 22 . If no, go to next step.
  17. Remove fuel sender assembly. Inspect fuel pump flex hose for damage, in-tank fuel pump harness connectors for poor connections, fuel strainer for a restriction and for contaminates in fuel tank. Did you find and correct the condition? If yes, go to step 22 . If no, go to step 21
  18. Turn OFF the ignition. Raise fuel rail, with fuel pipes connected. Turn ON the ignition, with the engine OFF. Command fuel pump ON with scan tool. Locate and replace leaking fuel injector. After repairs, go to step 22 .
  19. Locate and repair restricted fuel return pipe. After repairs, go to step 22 .
  20. Replace fuel pressure regulator. After repairs, go to step 22 .
  21. Replace fuel pump. After repairs, go to next step.
  22. Operate system in order to verify repair. Did you correct the condition? If yes, system is okay. If no, go to step 3 .

The number below refers to the step number in the diagnostic test.

  1. 2) This step verifies that the fuel pump is operating.
  2. 4) This step tests for an internal fuel leak. If the fuel pressure decreases during this test, an internal loss of pressure is indicated.
  3. 6) This step tests the fuel pressure regulator. The fuel pressure regulator is controlled by engine vacuum. With engine vacuum applied, the pressure should decrease by the specified value.
  4. 8) This step tests for a loss of fuel pressure between the shut-off adaptor on the fuel feed pipe and the fuel pump.
  5. 9) This step tests for a leaking fuel injector or a leaking fuel pressure regulator. If the fuel pressure remains constant during this test, the fuel injectors are not leaking fuel.
  6. 12) This step tests for a restricted fuel return pipe. If the fuel pressure is within the specified values, a restriction in the fuel return pipe is indicated.
  7. 14) This step determines if the fuel pressure regulator or the fuel pump is the cause of the low fuel pressure. If the pressure rises above the specified value, the fuel pump is okay.
  8. 16) This step verifies that a circuit condition is not the cause of a fuel pressure concern. Inspect all of the fuel pump electrical circuits thoroughly.
  9. 18) This step inspects the fuel pressure regulator for a fuel leak from the vacuum port. If fuel leaks from the fuel pressure regulator while the fuel pump is commanded ON, replace the fuel pressure regulator.
  1. Did you perform a Diagnostic System Check-Engine Controls? If yes, go to next step. If no, perform DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in «SELF-DIAGNOSTICS - 4.3L ASTRO, BLAZER, JIMMY CANADIAN, SAFARI, SONOMA & S10 PICKUP»(ref-137937) or «SELF-DIAGNOSTICS - 4.3L SIERRA & SILVERADO»(/chevrolet/silverado-2500/2000-2004/remont/testing-diagnostics/#engine-controls-self-diagnostics-43l) article.
  2. Inspect the fuel system for damage or external leaks before proceeding with this diagnostic. Turn ON the ignition, with the engine OFF. Command the fuel pump ON with a scan tool. Does the fuel pump operate? If yes, go to next step. If no, go to FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS under FUEL SYSTEMS (GASOLINE) in SYSTEM & COMPONENT TESTING - TRUCKS article.
  3. Verify there is adequate fuel in the fuel tank before proceeding with this diagnostic. Turn OFF the ignition. Turn OFF all accessories. Install the fuel pressure gauge. Turn ON the ignition, with the engine OFF. It may be necessary to command the fuel pump ON a few times in order to obtain the highest possible fuel pressure. DO NOT start the engine. Command the fuel pump ON with a scan tool. Observe the fuel pressure gauge, with the fuel pump commanded ON. Is the fuel pressure 60-66 psi (415-455 kPa) for VIN W models or 55-62 psi (379-427 kPa) for VIN X models? If yes, go to next step. If no, go to step 10 . NOTE: To identify model Vehicle Identification Number (VIN), see «GENERAL MOTORS INTRODUCTION - TRUCKS»(ref-132862) article.
  4. The fuel pressure may vary slightly when the fuel pump stops operating. After the fuel pump stops operating, the fuel pressure should stabilize and remain constant. Monitor the fuel pressure gauge for 1 minute. Does the fuel pressure decrease by more than 5 psi (34 kPa). If yes, go to step 8 . If no, go to next step.
  5. Relieve the fuel pressure to 10 psi (69 kPa). Monitor the fuel pressure gauge for 5 minutes. Does the fuel pressure decrease by more than 2 psi (14 kPa)? If yes, go to step 22 . If no, go to next step.
  6. Turn ON the ignition, with the engine OFF. Monitor the fuel pressure gauge. Start the engine. Does the fuel pressure decrease by 3-10 psi (21-69 kPa) when the engine is started? If yes, go to next step. If no, go to step 21 .
  7. Operate the vehicle within the conditions of the customer's concern. Monitor the fuel related parameters with a scan tool. Do any of the scan tool parameters indicate a lean condition? If yes, go to step 15 . If no, diagnose by symptom. See «SYMPTOMS (GASOLINE)»(ref-149956-S34497139172002110400000) in TROUBLE SHOOTING - NO CODES - TRUCKS article.
  8. Turn OFF the ignition. Relieve the fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-149936-S30080408262002110100000) under BASIC FUEL SYSTEM CHECKS (GASOLINE). Remove the EVAP canister. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Disconnect the rear fuel feed pipe and the rear fuel return pipe from the chassis fuel pipes. Drain any remaining fuel into an approved gasoline container. Install the fuel pipe shut-off adapters between the rear fuel pipes and the chassis fuel pipes. Open the valves on the fuel pipe shut-off adapters. Turn ON the ignition, with the engine OFF. Command the fuel pump ON with a scan tool. Bleed the air from the fuel pressure gauge. Command the fuel pump ON and then OFF with a scan tool. Close the fuel feed pipe shut-off valve. Monitor the fuel pressure gauge for 1 minute. Does the fuel pressure remain constant at 3-10 psi (21-69 kPa)? If yes, go to step 17 . If no, go to next step.
  9. Turn OFF the ignition. Open the fuel feed pipe shut-off valve. Turn ON the ignition, with the engine OFF. Command the fuel pump ON and then OFF with a scan tool. Close the fuel return pipe shut-off valve. Monitor the fuel pressure gauge for 1 minute. Does the fuel pressure remain constant? If yes, go to step 21 . If no, go to step 18 .
  10. Is the fuel pressure more than 66 psi (455 kPa) for VIN W models or 62 psi (427 kPa) for VIN X models? If yes, go to step 12 . If no, go to next step.
  11. Is the fuel pressure more than 0 psi (0 kPa)? If yes, go to step 14 . If no, go to step 15 .
  12. Turn OFF the ignition. Relieve the fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-149936-S30080408262002110100000) under BASIC FUEL SYSTEM CHECKS (GASOLINE). Remove the EVAP canister. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Disconnect the rear fuel return pipe from the chassis pipe. Attach a length of flexible hose to the chassis fuel pipe. Place the open end of the flexible fuel hose into an approved gasoline container. Turn ON the ignition, with the engine OFF. Monitor the fuel pressure gauge while the fuel pump is operating. Is the fuel pressure 60-66 psi (415-455 kPa) for VIN W models or 55-62 psi (379-427 kPa) for VIN X models? If yes, go to step 20 . If no, go to next step.
  13. Inspect the fuel rail outlet passage and the fuel return chassis pipe for a restriction. Did you find and correct the condition? If yes, go to step 23 . If no, go to step 21 .
  14. Turn OFF the ignition. Relieve the fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-149936-S30080408262002110100000) under BASIC FUEL SYSTEM CHECKS (GASOLINE). Remove the EVAP canister. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Disconnect the rear fuel return pipe from the chassis pipe. Install the fuel pipe shut-off adapter between the rear fuel return pipe and the chassis fuel pipe. Open the valve in the fuel pipe shut-off adapter. Turn ON the ignition, with the engine OFF. Bleed the air from the fuel system. Monitor the fuel pressure gauge. DO NOT allow the fuel pressure to exceed 75 psi (517 kPa). Excessive pressure may damage the fuel system. Slowly close the valve in the fuel return pipe shut-off adapter. Command the fuel pump ON with a scan tool. Does the fuel pressure increase to more than 66 psi (455 kPa) for VIN W models or 62 psi (427 kPa) for VIN X models? If yes, go to step 21 . If no, go to next step.
  15. Inspect the fuel filter and fuel feed pipe for restrictions. Did you find and correct the condition? If yes, go to step 23 . If no, go to next step.
  16. Inspect the harness connectors and the ground circuits of the fuel pump for poor connections. Did you find and correct the condition? If yes, go to step 23 . If no, go to next step.
  17. Remove the fuel sender assembly. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Inspect the following items: The fuel pump flex hose for damage. The in-tank fuel pump harness connectors for poor connections. The fuel strainer for a restriction. Contaminants in the fuel tank. Did you find and correct the condition? If yes, go to step 23 . If no, go to step 22 .
  18. Open the fuel return pipe shut-off valve. Remove the fuel meter body. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Install the engine compartment fuel feed and fuel return pipes to the fuel meter body. Turn ON the ignition, with the engine OFF. Inspect for a fuel leak from the fuel pressure regulator. Is the fuel pressure regulator leaking fuel? If yes, go to step 21 . If no, go to next step.
  19. Remove the fuel injector poppet nozzles from the intake manifold in order to isolate the leaking fuel injector. See appropriate REMOVAL, OVERHAUL & INSTALLATION article.
  20. Locate and repair the restricted fuel return pipe between the chassis fuel pipe and the fuel tank. Did you complete the repair? After repair is complete, go to 23 .
  21. Inspect for a missing or damaged "O" ring seal before replacing the fuel pressure regulator. Replace the fuel pressure regulator. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repair is complete, go to 23 .
  22. Replace the fuel pump. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repair is complete, go to next step.
  23. Operate the system in order to verify the repair. Did you correct the condition? If yes, system is okay. If no, go to step 3 .

When ignition is on, Powertrain Control Module (PCM) will activate in-tank fuel pump. In-tank fuel pump will remain ON as long as engine is cranking or running and PCM is receiving ignition reference pulses. If there are no ignition reference pulses, PCM will turn in-tank fuel pump OFF 2 seconds after ignition is turned ON or 2 seconds after engine stops running. In-tank fuel pump is an electric pump attached to fuel sender assembly. Fuel pump is designed to provide fuel at a pressure above pressure needed by fuel injectors. A fuel pressure regulator, attached to fuel rail, keeps fuel available to fuel injectors at a regulated pressure. Unused fuel is returned to fuel tank by a separate fuel return pipe.

The numbers below refer to the step numbers in the diagnostic procedure.

  1. 2 This step verifies that fuel pump is operating.
  2. 4 This step tests for an internal fuel leak. If fuel pressure drops during this test, an internal loss of pressure is indicated.
  3. 6 This step tests fuel pressure regulator. Fuel pressure regulator is controlled by engine vacuum. With engine vacuum applied, pressure should drop specified value.
  4. 9 This step inspects fuel pressure regulator for a fuel leak from vacuum port. If fuel leaks from fuel pressure regulator while fuel pump is commanded ON, replace fuel pressure regulator.
  5. 10 This step tests for a loss of fuel pressure between fuel feed pipe shut-off adapter and fuel pump.
  6. 11 This step tests for a leaking fuel injector, or fuel pressure regulator. If fuel pressure remains constant during this test, fuel injectors are not leaking fuel.
  7. 14 This step tests for a restricted fuel return pipe. If fuel pressure is within specified values, a restriction in fuel return pipe is indicated.
  8. 16 This step determines if fuel pressure regulator, or fuel pump, is cause of low fuel pressure. If pressure rises above specified value, fuel pump is okay.
  9. 18 This step verifies that a circuit condition is not the cause of a fuel pressure concern. Inspect all fuel pump electrical circuits thoroughly.
  1. Perform OBD system check. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in «SELF-DIAGNOSTICS - 4.8L, 5.3L & 6.0L "C" & "K" SERIES TRUCKS»(/chevrolet/silverado-2500/2000-2004/remont/testing-diagnostics/#engine-control-system-self-diagnostics-48l-53l-60l) or «SELF-DIAGNOSTICS - 8.1L "C", "G" & "K" SERIES TRUCKS»(/chevrolet/silverado-2500/2000-2004/remont/testing-diagnostics/#engine-control-system-self-diagnostics-81l-c-g-k-series-trucks) article. After performing OBD system check, go to next step.
  2. Turn ignition on, with engine off. Using scan tool, command fuel pump ON. If fuel pump operates, go to next step. If fuel pump does not operate, go to FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS under FUEL SYSTEMS (GASOLINE) in SYSTEM & COMPONENT TESTING - TRUCKS - EXCEPT TRACKER article.
  3. Turn ignition off. Ensure all accessories are off. Relieve fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-149936-S30080408262002110100000) . Install Fuel Pressure Gauge (J-34730-1A). Place fuel pressure gauge bleed hose into an approved gasoline container. Turn ignition on. Using scan tool, command fuel pump ON. Bleed air from fuel pressure gauge. It may be necessary to command fuel pump ON several times to obtain highest fuel pressure possible. DO NOT start engine. Observe fuel pressure with fuel pump operating. Fuel pressure should be 55-62 psi (385-425 kPa). If fuel pressure is within specification, go to next step. If fuel pressure is not within specification, go to step 12 .
  4. Monitor fuel pressure for one minute after fuel pump stops operating. If fuel pressure decreases more than 5 psi (34 kPa) in one minutes, go to step 9 . If fuel pressure does not decrease more than 5 psi (0.3 kg/cm 2 ) in 10 minutes, go to next step.
  5. Relieve fuel pressure until pressure is 10 psi (69 kPa). Monitor fuel pressure gauge for 5 minutes. If fuel pressure decreases more than 2 psi (14 kPa) in 5 minutes, go to step 24 . If fuel pressure decreases 2 psi (14 kPa) or less in 5 minutes, go to next step.
  6. Turn ignition off for 15 seconds. Turn ignition on, with engine off. Monitor fuel pressure gauge. Start engine. If fuel pressure decreases 3-10 psi (21-69 kPa) when engine is started, go to next step. If fuel pressure does not decrease 3-10 psi (21-69 kPa) when engine is started, go to step 8 .
  7. Operate vehicle within conditions of customer's concern. Using scan tool, monitor fuel related parameters. If any scan tool parameters indicate a lean condition, go to step 16 . If no scan tool parameters indicate a lean condition, go to «SYMPTOMS (GASOLINE)»(ref-149956-S34497139172002110400000) in TROUBLE SHOOTING - NO CODES - TRUCKS article.
  8. Disconnect vacuum hose from fuel pressure regulator. Monitor fuel pressure gauge. Start engine and allow it to idle. Using a hand-held vacuum pump, apply vacuum (12-14 in. Hg) to fuel pressure regulator. If fuel pressure decreases by 3-10 psi (21-69 kPa), go to step 21 . If fuel pressure does not decrease by 3-10 psi (21-69 kPa), go to step 23 .
  9. Turn ignition off. Remove vacuum hose from fuel pressure regulator. Turn ignition on, with engine off. Using scan tool, command fuel pump ON. Inspect for a fuel leak from fuel pressure regulator vacuum port. If fuel pressure regulator is leaking fuel, go to step 23 . If fuel pressure regulator is not leaking fuel, go to next step.
  10. Turn ignition off. Relieve fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-149936-S30080408262002110100000) . Disconnect fuel feed hose and fuel return hose from fuel rail pipes. Install Fuel Line Shutoff Adapters (J-37287) between fuel hoses and fuel rail pipes. Open both valves on shutoff adapters. Turn ignition on, with engine off. Using scan tool, command fuel pump ON and then OFF. Close shutoff valve at fuel feed line. Monitor fuel pressure gauge for one minute. If fuel pressure remains constant, go to step 19 . If fuel pressure does not remain constant, go to next step.
  11. Turn ignition off. Open shutoff valve at fuel feed line. Turn ignition, with engine off. Using scan tool, command fuel pump On and then OFF. Close shutoff valve at fuel return line. Monitor fuel pressure gauge for one minute. If fuel pressure remains constant, go to step 23 . If fuel pressure does not remain constant, go to step 20 .
  12. If fuel pressure is greater than 62 psi (427 kPa), go to step 14 . If fuel pressure is 62 psi (427 kPa) or less, go to next step.
  13. If fuel pressure is greater than zero psi, go to step 16 . If fuel pressure is zero psi, go to step 17
  14. Turn ignition off. Relieve fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-149936-S30080408262002110100000) . Disconnect fuel return hose from fuel rail return pipe. Attach flexible fuel hose to fuel rail outlet passage. Place other end of flexible hose into an approved gasoline container. Turn ignition on, with engine off. Monitor fuel pressure gauge while fuel pump is operating. If fuel pressure is 55-62 psi (385-425 kPa), go to step 22 . If fuel pressure is not as specified, go to next step.
  15. Inspect fuel rail return pipe and fuel rail outlet passage for restriction. Repair as necessary. After repairs, go to step 25 . If no restriction is found, go to step 23 .
  16. Turn ignition off. Relieve fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-149936-S30080408262002110100000) . Disconnect fuel return hose from fuel rail return pipe. Install Fuel Line Shutoff Adapters (J-37287) between fuel return pipe and fuel rail. Open valve on shutoff adapter at fuel pipe. Turn ignition on, with engine off. Using scan tool, command fuel pump ON. Bleed air from fuel system. Monitor fuel pressure gauge. Gradually close valve on shutoff adapter at fuel return pipe. Using scan tool, command fuel pump ON. If fuel pressure increases to more than 62 psi (425 kPa), go to step 23 . If fuel pressure does not increase to more than 62 psi (4.4 kg/cm 2 ), go to next step.
  17. Inspect fuel filter and fuel feed pipe for restriction. Repair as necessary. After repairs, go to step 25 . If no restriction is found, go to next step.
  18. Inspect harness connectors and ground circuits of fuel pump for poor connections. See «WIRING DIAGRAMS»(/chevrolet/silverado-2500/2000-2004/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams) article. Repair as necessary. After repairs, go to step 25 . If connectors and ground circuits are okay, go to next step.
  19. Remove fuel sending unit assembly. Inspect fuel pump flex hose for damage, in tank fuel pump harness connectors for poor connections, fuel strainer for a restriction and for contaminates in fuel tank. Repair as necessary. After repairs, go to step 25 . If no problem is found, go to step 24 .
  20. Turn ignition off. Loosen and raise fuel rail with fuel lines connected. Turn ignition on, with engine off. Using scan tool, command fuel pump ON. Locate and replace leaking fuel injector. After repairs, go to step 25 .
  21. Locate and repair loss of vacuum to fuel pressure regulator. After repairs, go to step 25 .
  22. Locate and repair restriction in fuel return line. After repairs, go to step 25 .
  23. Replace fuel pressure regulator. After repairs, go to step 25 .
  24. Replace fuel pump assembly. After repairs, go to next step.
  25. Operate system to verify repair. If condition has been corrected, system is okay. If system is not okay, repeat step 3 .

Symptom Description

When you turn ON the ignition switch, the Powertrain Control Module (PCM) energizes the fuel pump relay which powers the fuel pump ON. The pump remains ON as long as the engine is cranking or running and the PCM receives reference pulses. If there are no reference pulses, the PCM shuts the fuel pump OFF within 2 seconds after the ignition was switched to the ON position or if the engine stops. An electric fuel pump pumps the fuel through an in-line filter to the fuel meter body assembly. The pump attaches to the fuel sender assembly inside of the fuel tank. The fuel pump provides fuel pressure above what is needed by the fuel injectors. The pressure regulator keeps the fuel available to the injectors at a regulated pressure. Unused fuel returns to the fuel tank by the fuel return pipe.

The number below refers to the step number in the diagnostic test.

  1. 2) This step verifies that the fuel pump is operating.
  2. 4) This step tests for an internal fuel leak. If the fuel pressure decreases during this test, an internal loss of pressure is indicated.
  3. 6) This step tests the fuel pressure regulator. The fuel pressure regulator is controlled by engine vacuum. With engine vacuum applied, the pressure should decrease by the specified value.
  4. 8) This step tests for a loss of fuel pressure between the shut-off adaptor on the fuel feed pipe and the fuel pump.
  5. 9) This step tests for a leaking fuel injector or a leaking fuel pressure regulator. If the fuel pressure remains constant during this test, the fuel injectors are not leaking fuel.
  6. 12) This step tests for a restricted fuel return pipe. If the fuel pressure is within the specified values, a restriction in the fuel return pipe is indicated.
  7. 14) This step determines if the fuel pressure regulator or the fuel pump is the cause of the low fuel pressure. If the pressure rises above the specified value, the fuel pump is okay.
  8. 16) This step verifies that a circuit condition is not the cause of a fuel pressure concern. Inspect all of the fuel pump electrical circuits thoroughly.
  9. 18) This step inspects the fuel pressure regulator for a fuel leak from the vacuum port. If fuel leaks from the fuel pressure regulator while the fuel pump is commanded ON, replace the fuel pressure regulator.
  1. Did you perform a Diagnostic System Check-Engine Controls? If yes, go to next step. If no, perform DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article.
  2. Inspect the fuel system for damage or external leaks before proceeding with this diagnostic. Turn ON the ignition, with the engine OFF. Command the fuel pump ON with a scan tool. Does the fuel pump operate? If yes, go to next step. If no, go to FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS under FUEL SYSTEMS (GASOLINE) in SYSTEM & COMPONENT TESTING - TRUCKS article.
  3. Verify there is adequate fuel in the fuel tank before proceeding with this diagnostic. Turn OFF the ignition. Turn OFF all accessories. Install the fuel pressure gauge. Turn ON the ignition, with the engine OFF. It may be necessary to command the fuel pump ON a few times in order to obtain the highest possible fuel pressure. DO NOT start the engine. Command the fuel pump ON with a scan tool. Observe the fuel pressure gauge, with the fuel pump commanded ON. Is the fuel pressure 60-66 psi (415-455 kPa)? If yes, go to next step. If no, go to step 10 .
  4. The fuel pressure may vary slightly when the fuel pump stops operating. After the fuel pump stops operating, the fuel pressure should stabilize and remain constant. Monitor the fuel pressure gauge for 1 minute. Does the fuel pressure decrease by more than 5 psi (34 kPa). If yes, go to step 8 . If no, go to next step.
  5. Relieve the fuel pressure to 10 psi (69 kPa). Monitor the fuel pressure gauge for 5 minutes. Does the fuel pressure decrease by more than 2 psi (14 kPa)? If yes, go to step 22 . If no, go to next step.
  6. Turn ON the ignition, with the engine OFF. Monitor the fuel pressure gauge. Start the engine. Does the fuel pressure decrease by 3-10 psi (21-69 kPa) when the engine is started? If yes, go to next step. If no, go to step 21 .
  7. Operate the vehicle within the conditions of the customer's concern. Monitor the fuel related parameters with a scan tool. Do any of the scan tool parameters indicate a lean condition? If yes, go to step 15 . If no, diagnose by symptom. See «SYMPTOMS (GASOLINE)»(ref-149956-S34497139172002110400000) in TROUBLE SHOOTING - NO CODES - TRUCKS article.
  8. Turn OFF the ignition. Relieve the fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-149936-S30080408262002110100000) under BASIC FUEL SYSTEM CHECKS (GASOLINE). Remove the EVAP canister. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Disconnect the rear fuel feed pipe and the rear fuel return pipe from the chassis fuel pipes. Drain any remaining fuel into an approved gasoline container. Install the fuel pipe shut-off adapters between the rear fuel pipes and the chassis fuel pipes. Open the valves on the fuel pipe shut-off adapters. Turn ON the ignition, with the engine OFF. Command the fuel pump ON with a scan tool. Bleed the air from the fuel pressure gauge. Command the fuel pump ON and then OFF with a scan tool. Close the fuel feed pipe shut-off valve. Monitor the fuel pressure gauge for 1 minute. Does the fuel pressure remain constant at 3-10 psi (21-69 kPa)? If yes, go to step 17 . If no, go to next step.
  9. Turn OFF the ignition. Open the fuel feed pipe shut-off valve. Turn ON the ignition, with the engine OFF. Command the fuel pump ON and then OFF with a scan tool. Close the fuel return pipe shut-off valve. Monitor the fuel pressure gauge for 1 minute. Does the fuel pressure remain constant? If yes, go to step 21 . If no, go to step 18 .
  10. Is the fuel pressure more than 66 psi (455 kPa)? If yes, go to step 12 . If no, go to next step.
  11. Is the fuel pressure more than 0 psi (0 kPa)? If yes, go to step 14 . If no, go to step 15 .
  12. Turn OFF the ignition. Relieve the fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-149936-S30080408262002110100000) under BASIC FUEL SYSTEM CHECKS (GASOLINE). Remove the EVAP canister. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Disconnect the rear fuel return pipe from the chassis pipe. Attach a length of flexible hose to the chassis fuel pipe. Place the open end of the flexible fuel hose into an approved gasoline container. Turn ON the ignition, with the engine OFF. Monitor the fuel pressure gauge while the fuel pump is operating. Is the fuel pressure 60-66 psi (415-455 kPa)? If yes, go to step 20 . If no, go to next step.
  13. Inspect the fuel rail outlet passage and the fuel return chassis pipe for a restriction. Did you find and correct the condition? If yes, go to step 23 . If no, go to step 21 .
  14. Turn OFF the ignition. Relieve the fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-149936-S30080408262002110100000) under BASIC FUEL SYSTEM CHECKS (GASOLINE). Remove the EVAP canister. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Disconnect the rear fuel return pipe from the chassis pipe. Install the fuel pipe shut-off adapter between the rear fuel return pipe and the chassis fuel pipe. Open the valve in the fuel pipe shut-off adapter. Turn ON the ignition, with the engine OFF. Bleed the air from the fuel system. Monitor the fuel pressure gauge. DO NOT allow the fuel pressure to exceed 75 psi (517 kPa). Excessive pressure may damage the fuel system. Slowly close the valve in the fuel return pipe shut-off adapter. Command the fuel pump ON with a scan tool. Does the fuel pressure increase to more than 66 psi (455 kPa)? If yes, go to step 21 . If no, go to next step.
  15. Inspect the fuel filter and fuel feed pipe for restrictions. Did you find and correct the condition? If yes, go to step 23 . If no, go to next step.
  16. Inspect the harness connectors and the ground circuits of the fuel pump for poor connections. Did you find and correct the condition? If yes, go to step 23 . If no, go to next step.
  17. Remove the fuel sender assembly. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Inspect the following items: The fuel pump flex hose for damage. The in-tank fuel pump harness connectors for poor connections. The fuel strainer for a restriction. Contaminants in the fuel tank. Did you find and correct the condition? If yes, go to step 23 . If no, go to step 22 .
  18. Open the fuel return pipe shut-off valve. Remove the fuel meter body. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Install the engine compartment fuel feed and fuel return pipes to the fuel meter body. Turn ON the ignition, with the engine OFF. Inspect for a fuel leak from the fuel pressure regulator. Is the fuel pressure regulator leaking fuel? If yes, go to step 21 . If no, go to next step.
  19. Remove the fuel injector poppet nozzles from the intake manifold in order to isolate the leaking fuel injector. See appropriate REMOVAL, OVERHAUL & INSTALLATION article.
  20. Locate and repair the restricted fuel return pipe between the chassis fuel pipe and the fuel tank. Did you complete the repair? After repair is complete, go to 23 .
  21. Inspect for a missing or damaged "O" ring seal before replacing the fuel pressure regulator. Replace the fuel pressure regulator. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repair is complete, go to 23 .
  22. Replace the fuel pump. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repair is complete, go to next step.
  23. Operate the system in order to verify the repair. Did you correct the condition? If yes, system is okay. If no, go to step 3 .

More articles — Engine Controls - Basic Diagnostic Procedures