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Starting System: Diagnosis Chevrolet Silverado 2500

Starter 1 illustration ~2433 words

TROUBLE SHOOTING

Note. For information not covered in this article, see * STARTER - GENERAL TROUBLE SHOOTING * .

Note condition and operation of SECURITY indicator light. If SECURITY indicator light stays on or flashes continuously, repair anti-theft system as necessary. See appropriate ANTI-THEFT SYSTEMS in DOOR LOCKS & ANTI-THEFT SYSTEMS. Verify customer complaint by operating suspected system. Visually inspect for obvious signs of mechanical and electrical damage. Inspect for loose or corroded connections, damaged wiring harnesses and/or switches. Check for a broken or partially broken wire inside insulation, which could cause system malfunction but prove good in a continuity/voltage check with system disconnected. Ensure any aftermarket electronic equipment is properly installed. If fault is found, repair as necessary. If no fault is found, perform self-diagnostics. See SELF-DIAGNOSTIC SYSTEM .

DIAGNOSTIC STARTING POINT (ENGINE ELECTRICAL)

Begin the system diagnosis with the DIAGNOSTIC SYSTEM CHECK (ENGINE ELECTRICAL) . The diagnostic system check will provide the following information

  1. The identification of the control module(s) which command the system.
  2. The ability of the control module(s) to communicate through the serial data circuit.
  3. The identification of any stored diagnostic trouble codes (DTCs) and their status.

The use of the diagnostic system check will identify the correct procedure for diagnosing the system and where the procedure is located.

ON-VEHICLE TESTING

WARNINGVehicles are equipped with air bag supplemental restraint system. Before attempting any repairs involving steering column, instrument panel or related components, see the following applicable procedures: For pickups, see AIR BAG SAFETY PRECAUTIONS and DISABLING & ACTIVATING AIR BAG SYSTEM . For utility vehicles, see AIR BAG SAFETY PRECAUTIONS and DISABLING & ACTIVATING AIR BAG SYSTEM .
CAUTIONWhen battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES before disconnecting battery.

Note. Some vehicles are equipped with optional dual batteries.

BATTERY TESTING & INSPECTION

  1. For pickups, see «BATTERY TESTING & INSPECTION»(ref-167919-S01980806492004102500000) .
  2. For utility vehicles, see «BATTERY TESTING & INSPECTION»(ref-138808-S14476191862002042300000) .

SELF-DIAGNOSTIC SYSTEM

Note. Diagnostic trouble code tests are written specifically for use with GM Tech I or Tech II scan tools. Generic scan tool can be used but may have limited functions. This article only covers the portion of those systems which relates to starting system diagnosis. For further information, see appropriate SELF-DIAGNOSTICS.

DIAGNOSTIC SYSTEM CHECK (ENGINE ELECTRICAL)

  1. Did you perform the Battery Inspection/Test? If so, go to next step. If not, go to «BATTERY TESTING & INSPECTION»(ref-138814-S05794766772002042300000) under ON-VEHICLE TESTING.
  2. Install a scan tool. Does the scan tool power up? If so, go to step 4 . If not, go to SCAN TOOL DOES NOT POWER UP in BODY CONTROL MODULES.
  3. Access the CLASS 2 POWER MODE in the DIAGNOSTIC CIRCUIT CHECK on the scan tool. Rotate the ignition switch through OFF, RUN, and CRANK positions while observing the CLASS 2 POWER MODE on the scan tool. Does the CLASS 2 POWER MODE reading match the ignition switch positions for OFF, RUN and CRANK positions? If so, go to next step. If not, go to POWER MODE MISMATCH in BODY CONTROL MODULES.
  4. Turn on ignition, with engine off. Attempt to communicate with each module on the class 2 serial data circuit. If using a Tech 2, obtain this information using the CLASS 2 MESSAGE MONITOR feature. Does the scan tool communicate with any module on the class 2 serial data circuit? If so, go to next step. If not, go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE in BODY CONTROL MODULES.
  5. Select the Display DTCs function for each module. If using a Tech 2, use the CLASS 2 DTC CHECK feature in order to determine which modules have DTCs set. Record all of the displayed DTCs, the DTC status and the module which set the DTC. Does the scan tool display any DTCs? If so, go to next step. If not, go to «SYMPTOMS (ENGINE ELECTRICAL)»(ref-138814-S33469885152004111900000) .
  6. Does the scan tool display any DTC beginning with "U"? If so, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS. If not, go to next step.
  7. Does the scan tool display any DTC beginning with "P"? If so, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS. If not, go to next step.
  8. Does the scan tool display any DTC beginning with "B"? If so, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS in BODY CONTROL MODULES.

SYMPTOMS (ENGINE ELECTRICAL)

Note. The following steps must be completed before using the symptom tables.

  1. Perform «DIAGNOSTIC SYSTEM CHECK (ENGINE ELECTRICAL)»(ref-138814-S34310785332002042300000) before using the Symptom Tables in order to verify that all of the following are true: There are no DTCs set. The control module(s) can communicate via the serial data link.
  2. Review the system operation in order to familiarize yourself with the system functions. Refer to one of the following system operations: See «DESCRIPTION & OPERATION»(ref-138814-S13639750532002042300000) . For pickups, see DESCRIPTION & OPERATION in «CHARGING SYSTEM»(ref-167919-S25283736462004102500000) . For utility vehicles, see DESCRIPTION & OPERATION in «CHARGING SYSTEM»(ref-138808-S28914228232002042300000) .

Visual/Physical Inspection

  1. Inspect for aftermarket devices which could affect the operation of the starting and charging systems. See «CHECKING AFTERMARKET ACCESSORIES»(ref-138814-S21714933102004112200000) .
  2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

  1. See «TEST A: STARTER SOLENOID DOES NOT CLICK»(ref-138814-S11610974262002042300000) .
  2. See «TEST B: STARTER SOLENOID CLICKS, ENGINE DOES NOT CRANK»(ref-138814-S03429373362002042300000) .
  3. See «TEST C: ENGINE CRANKS SLOWLY»(ref-138814-S24049971652002042300000) .
  4. See «TEST D: STARTER NOISE DIAGNOSIS»(ref-138814-S19269494492002042300000) .
  5. See «BATTERY TESTING & INSPECTION»(ref-138814-S05794766772002042300000) .

Testing for Proper Terminal Contact

It is important to test terminal contact at the component and any in-line connectors before replacing a suspect component. Mating terminals must be inspected to ensure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation.

Contamination may be caused by the connector halves being improperly connected. A missing or damaged connector seal, damage to the connector itself, or exposing the terminals to moisture and dirt can also cause contamination. Contamination, usually in the underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit.

Deformation is caused by probing the mating side of a connector terminal without the proper adapter. Always use the GM-approved terminal test kit when probing connectors. Other causes of terminal deformation are improperly joining the connector halves, or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact causing an open or intermittently open circuit.

TEST A: STARTER SOLENOID DOES NOT CLICK

Note. The procedures within this test may refer to wiring information. When performing a test or repair on the systems wiring, see WIRING DIAGRAMS .

  1. Did you preform the DIAGNOSTIC SYSTEM CHECK (ENGINE ELECTRICAL)? If yes, proceed to next step. If no, see «DIAGNOSTIC SYSTEM CHECK (ENGINE ELECTRICAL)»(ref-138814-S34310785332002042300000) .
  2. Turn the ignition switch to the START position. Does the engine crank? If yes, see «INTERMITTENT OR POOR CONNECTIONS»(ref-138814-S25687806842004112200000) . If no, proceed to next step.
  3. Turn the ignition switch to the START position. Does the starter motor relay click? If yes, go to step 7 . If no, proceed to next step.
  4. Remove the starter motor relay. Connect a test light from the supply voltage circuit of the starter motor relay coil circuit to ground. With the transmission in park, or clutch pedal depressed, turn the ignition switch to the START position. Does the test light illuminate? If yes, proceed to next step. If no, go to step 6 .
  5. Connect a test light from the supply voltage circuit of the starter motor relay coil circuit to the control circuit of the starter motor relay coil circuit. With the transmission in park, or clutch pedal depressed, turn the ignition switch to the START position. Does the test light illuminate? If yes, go to step 13 . If no, go to step 10 .
  6. Turn off ignition. Disconnect the Park Neutral Position (PNP) switch. For Allison transmission, see «PARK/NEUTRAL POSITION SWITCH»(ref-138386-S28493444922002041000000) . For automatic transmission, see «PARK/NEUTRAL POSITION SWITCH»(ref-138559-S31260039142002041700000) . For manual transmission, see «CLUTCH START SWITCH»(ref-130806-S23033300322001120500000) . Turn on ignition, with engine off. Connect a 10 amp fused jumper between the starter motor relay coil control circuits of the PNP switch or clutch pedal position switch. With the transmission in park, or clutch pedal depressed, turn the ignition switch to the START position. Does the test lamp illuminate? If yes, go to step 14 . If no, go to step 11 .
  7. Turn off ignition. Disconnect the starter motor relay. Connect a test lamp between the battery positive voltage circuit of the starter motor relay switch circuit and a good ground. Does the test lamp illuminate? If yes, proceed to next step. If no, go to step 17 .
  8. Connect a 30 amp fused jumper between the battery positive voltage circuit of the starter motor relay switch circuit and the supply voltage circuit of the starter solenoid. Does the engine crank? If yes, go to step 13 . If no, proceed to next step.
  9. Does the fuse in the jumper open? If yes, go to step 18 . If no, go to step 12 .
  10. Test the control circuit of the starter motor relay for an open or high resistance. Did you find and correct the condition? If yes, go to step 23 . If no, go to step 19 .
  11. Test the supply voltage circuit of the starter motor relay coil circuit for an open or high resistance. Did you find and correct the condition? If yes, go to step 23 . If no, go to step 15 .
  12. Test the supply voltage circuit of the starter solenoid for an open or high resistance. Did you find and correct the condition? If yes, go to step 23 . If no, go to step 16 .
  13. Inspect for poor connections at the starter motor relay. Did you find and correct the condition? If yes, go to step 23 . If no, go to step 19 .
  14. If equipped with an automatic transmission, inspect for poor connection at the PNP switch harness connector. If okay, perform the park/neutral position switch adjustment. For automatic transmission, see «PARK/NEUTRAL POSITION SWITCH»(ref-138559-S20201209492002041700000) . For Allison transmission, see «PARK/NEUTRAL POSITION SWITCH»(ref-138386-S35374953412002040900000) . If equipped with a manual transmission, inspect for poor connection at the clutch pedal position switch harness connector. Did you find and correct the condition? If yes, go to step 23 . If no, go to step 20 .
  15. Inspect for poor connections at the ignition switch harness connector. Did you find and correct the condition? If yes, go to step 23 . If no, go to step 21 .
  16. Inspect for poor connections at the starter solenoid. Did you find and correct the condition? If yes, go to step 23 . If no, go to step 22 .
  17. Repair the open or high resistance in the battery positive voltage circuit of the starter motor relay switch circuit. When complete, go to step 23 .
  18. Repair the short to ground in the supply voltage circuit of the starter solenoid. When complete, go to step 23 .
  19. Replace the Starter Relay. When complete, go to step 23 .
  20. Replace the PNP switch. Replace the clutch pedal position switch. For Allison transmission, see «PARK/NEUTRAL POSITION SWITCH»(ref-138386-S28493444922002041000000) . For automatic transmission, see «PARK/NEUTRAL POSITION SWITCH»(ref-138559-S31260039142002041700000) . For manual transmission, see «CLUTCH PEDAL REPLACEMENT»(ref-130806-S04887120762001120600000) . When complete, go to step 23 .
  21. Replace the ignition switch. When complete, go to step 23 .
  22. Replace the starter. See «STARTER»(ref-138814-S16413176512002042300000) . When complete, proceed to next step.
  23. Operate the system for which the symptom occurred. Did you correct the condition? If yes, system is okay. If no, go to step 2 .

TEST B: STARTER SOLENOID CLICKS, ENGINE DOES NOT CRANK

For testing procedures (Scheme 1)

Scheme 1

Scheme 1: TEST B: STARTER SOLENOID CLICKS, ENGINE DOES NOT CRANK
Scheme 1: TEST B: STARTER SOLENOID CLICKS, ENGINE DOES NOT CRANK

TEST C: ENGINE CRANKS SLOWLY

Perform the following checks

  1. Battery - See «BATTERY TESTING & INSPECTION»(ref-138814-S05794766772002042300000) .
  2. Wiring - Inspect the wiring for damage. Inspect all connections to the starter motor, solenoid, battery, and all ground connections. See «INTERMITTENT OR POOR CONNECTIONS»(ref-138814-S25687806842004112200000) .
  3. Engine - Make sure the engine is not seized. See «GASOLINE ENGINE - MECHANICAL TROUBLE SHOOTING»(ref-27342-S03731861042001112800000) .

If the battery, the wiring and the engine are functioning properly and the engine continues to crank slowly, replace the starter motor. See

STARTER

TEST D: STARTER NOISE DIAGNOSIS

Note. Inspect the flywheel ring gear for damage or unusual wear.

Note. Shim the starter if applicable.

Note. In order to add pinion to ring gear clearance a full size shim must be used. Do not shim only one starter mounting bolt. There are 3 shims available in different shapes for clearance. All are 0.039" (1 mm) thick.

  1. Did you preform the DIAGNOSTIC SYSTEM CHECK (ENGINE ELECTRICAL)? If yes, proceed to next step. If no, see «DIAGNOSTIC SYSTEM CHECK (ENGINE ELECTRICAL)»(ref-138814-S34310785332002042300000) .
  2. Start the engine. Does the starter operate normally? If yes, see «INTERMITTENT OR POOR CONNECTIONS»(ref-138814-S25687806842004112200000) . If no, proceed to next step.
  3. Start the engine while listening to the starter motor turn. Is there a loud "whoop" which may sound like a siren if the engine is revved while the starter is engaged after the engine starts, but while the starter is still held in the engaged position? If yes, go to step 6 . If no, proceed to next step.
  4. Do you hear a "rumble", a "growl", or, in some cases, a "knock" as the starter is coasting down to a stop after starting the engine? If yes, go to step 7 . If no, proceed to next step.
  5. This is often diagnosed as a starter drive gear hang-in or a weak solenoid. When the engine is cranked, do you hear a high-pitched whine after the engine cranks and starts normally? If yes, go to step 8 . If no, go to step 7 .
  6. Inspect the flywheel ring gear for chipped gear teeth, missing gear teeth or milled teeth. Is the flywheel bent, or does it have damaged teeth? If yes, go to step 9 . If no, go to step 10 .
  7. Remove the starter motor. See «STARTER»(ref-138814-S16413176512002042300000) . Inspect the starter motor bushings and clutch gear. Does the clutch gear have chipped or milled teeth or worn bushings? If yes, go to step 10 . If no, go to step 9 .
  8. Shim the starter motor away from the flywheel by adding shims between the starter motor and the engine block one at a time. Flywheel runout may make this noise appear to be intermittent. When complete, go to step 11 .
  9. Replace the flywheel. See ENGINE FLYWHEEL in ENGINE MECHANICAL. When complete, go to step 11 .
  10. Replace the starter motor. See «STARTER»(ref-138814-S16413176512002042300000) . When complete, proceed to next step.
  11. 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 .

BENCH TESTING

Information is not available from manufacturer. Starter is not serviceable and must be replaced as a single unit to repair.

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