Starting System Cadillac Escalade GMT400

BODY DESIGNATIONS

BODY DESIGNATIONS

DESCRIPTION & OPERATION

Note. Information for Escalade and Envoy not available.

When the ignition switch is turned to the START position, the Delco-Remy starter solenoid windings are energized. This causes the solenoid plunger to move the shift lever, which engages the pinion with the engine flywheel ring gear. The movement of the plunger also closes the main solenoid contacts, applying battery voltage to the starter motor. (Scheme 1)

When the engine starts, the pinion will overrun, protecting the armature from excessive speed and the flywheel from damage. When the ignition switch is released, the plunger return spring disengages the pinion.

Starters with the PG designation have a pinion that is driven by a 5:1 gear reduction system. PG starters should not be disassembled, and serviceable only by complete replacement.

Starters with the 28MT designation, used on diesel engines, have a pinion that is driven by a gear reduction system.

Scheme 1

COMPONENT LOCATIONS

COMPONENT LOCATIONS

TROUBLE SHOOTING

Note. For information not covered in this article, see TROUBLE SHOOTING article in GENERAL INFORMATION.

TROUBLE SHOOTING HINTS

On all models, note condition of SECURITY indicator light. If indicator stays on or flashes continuously, see appropriate ANTI-THEFT SYSTEMS article in ACCESSORIES & EQUIPMENT. Check starter solenoid terminals and battery grounds. Check for proper installation of aftermarket electronic equipment. Perform self-diagnostic system test, to be certain no trouble codes are stored in PCM memory which may lead to misdiagnosis. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.

"C" & "K" Series

Check IGN A (40-amp) fuse and IGN C (20-amp) fuse in underhood fuse-relay center, and CRANK (10-amp) fuse in left instrument panel fuse block. Check battery and underhood fuse-relay center grounds.

"G" Series

Check IGN-A (40-amp) fuse located in underhood fuse-relay center. Check CRANK (10-amp) fuse located in instrument panel fuse block.

"L" & "M" Series

Check IGN-A (40-amp) fuse, located in underhood fuse-relay center. Check CRANK (10-amp) fuse in instrument panel fuse block.

"P" Series

Check CRANK fuse. See COMPONENT LOCATIONS table. Check fusible links.

"S" & "T" Series

Check BATTERY (175-amp) fuse. Check IGN C (20-amp) fuse and CRANK (10-amp) fuse in underhood electrical center.

"U" Series

Check IGN MAIN 1 (40-amp) fuse located in underhood electrical center.

ON-VEHICLE TESTING

Note. The following tests assume that engine and battery are operating normally and are at normal operating temperature, battery is charged, there are no engine problems that would cause a no-start condition, and no diagnostic trouble codes are present.

STARTER NOISE

Note. Check flywheel ring gear for damage.

1. A high-pitched whine, heard while cranking (before engine starts), indicates excessive distance between starter pinion and flywheel. If high-pitched whine is heard after engine starts and key is released, distance between starter pinion and flywheel is too small. Locate high spot on flywheel before checking pinion-to-flywheel clearance. Pinion-to-flywheel clearance should be.02-.06" (.5-1.5 mm). (Scheme 2)
2. If loud, siren-like whoop sound is heard after the engine starts, drive assembly is likely defective. If rumble, growl or knock is present as starter is coasting to a stop, after starting engine, starter armature is bent or unbalanced.
3. If diagnosis indicates pinion should be closer to flywheel, ensure proper starter motor was installed. During initial starter motor installation, shim(s) are not used. If shim(s) are present, remove as necessary.
4. If diagnosis indicates starter should be moved away from flywheel, add shims as necessary. If using.039" (1.0 mm) long shims, do not exceed 2 shims. If using.015" (.38 mm) long shims, do not exceed 3 shims. If condition is not corrected, and pinion-to-flywheel clearance has been reached, short shims may be added to outer side of starter motor bolt using.015" (.38 mm) shims. For starter removal, see «STARTER»(/cadillac/escalade/gmt400-1998-2000/remont/starter/#starting-system) under REMOVAL & INSTALLATION.

Scheme 2

STARTER DRAW TEST (DIESEL)

1. Disable fuel system. On "C" and "K" diesel models, remove fuel pump relay, located in underhood fuse-relay center. On "P" diesel models, disconnect fuel injection pump fuel shut off solenoid connector, located on engine, in front of throttle body.
2. On all models, connect ammeter to negative battery cable. Crank engine and observe ammeter readings. If readings are more than 360 amps, replace starter assembly. If readings are less than 300 amps, replace battery cable or connections.

SLOW OR NO CRANK ONLY AFTER EXTENDED PERIODS OF VEHICLE NON-USE

There may be a parasitic load on electrical system. See PARASITIC LOAD EXPLANATION & TEST PROCEDURES article in GENERAL INFORMATION.

1. Connect DVOM between starter solenoid terminal "S" (Purple wire) and ground. Place gear selector in Park (A/T), or depress clutch pedal (M/T). Turn ignition switch to START position. If battery voltage is not present, go to next step. If battery voltage is present, clean starter, starter mounting bolts and mounting surface. Recheck voltage. If battery voltage is still present, replace starter.
2. Remove starter relay located in underhood fuse-relay center. See «COMPONENT LOCATIONS»(/cadillac/escalade/gmt400-1998-2000/remont/starter/#starting-system__component-locations) table. Connect test light between starter relay connector cavity No. 30 (Red wire) and ground. If test light illuminates, go to next step. If test light does not illuminate, repair open in Red wire between starter relay and IGN-A (40-amp) fuse located in underhood fuse-relay center. Reinstall starter relay.
3. Disconnect Purple wire from starter solenoid terminal "S". Connect a DVOM between Purple wire and ground. Turn ignition switch to START position. If reading is greater than 9.5 volts, go to next step. If test light does not illuminate, repair open in Purple wire circuit between starter relay and starter solenoid. Reinstall starter relay.
4. Using DVOM, check continuity of Black wire between starter relay connector cavity No. 86 and ground. If continuity exists, go to next step. If continuity does not exist, repair open in Black wire circuit between starter relay and ground. Reinstall starter relay.
5. Place gear selector in Park (A/T), or depress clutch pedal (M/T). Connect test light between starter relay cavity No. 85 and ground. Turn ignition switch to START position and observe test light. If test light illuminates, replace starter relay. If test light does not illuminate, reinstall starter relay and go to next step (M/T), or step 8 (A/T).
6. On M/T models, disconnect Clutch Pedal Position (CPP) switch connector. Turn ignition switch to START position. Using DVOM, measure voltage between CPP switch connector terminal "C" (Purple/White wire) and ground. If voltage is not present, go to step 10 . If battery voltage is present, go to next step.
7. Connect a fused jumper wire between terminals of CPP switch connector. Turn ignition switch to START position. If engine cranks, replace CPP switch. If engine does not crank, repair open in Purple/White wire circuit between CPP switch and starter relay.
8. On A/T models, disconnect Park Neutral Position (PNP) switch. Connect DVOM between PNP switch connector terminal "E" (Purple/White wire) and ground. Turn ignition switch to START position. If battery voltage is not present, go to step 10 . If battery voltage is present, go to next step.
9. Connect a fused jumper wire between PNP switch connector terminals "E" (Purple/White wire) and "G" (Yellow wire). Turn ignition switch to START position. If engine cranks, replace PNP switch. If engine does not crank, repair open in Yellow wire between PNP switch connector terminal "G" and starter relay cavity No. 85.
10. On all models, turn ignition switch to START position. Using test light, check for power at CRANK (10-amp) fuse. If voltage is not present, go to next step. If battery voltage is present, repair open in Purple wire between left instrument panel fuse block and CPP or PNP switch.
11. Using DVOM, measure voltage between Red wire terminal of ignition switch connector and ground. If battery voltage is present, replace ignition switch. If battery voltage is not present, repair open in Red wire circuit between ignition switch and No. 6 (40-amp) fuse located in underhood fuse-relay center.

1. Connect DVOM between starter solenoid connector terminal "S" (Purple wire) and engine ground. Place gear selector in Park. Turn ignition switch to START position. If battery voltage exists, go to next step. If battery voltage does not exist, go to step 4.
2. Clean starter motor mounting bolts, starter motor and mounting surfaces. Install starter and repeat test. If starter still does not engage, go to next step.
3. Replace starter. Recheck system.
4. Remove starter relay from underhood fuse-relay center. See «COMPONENT LOCATIONS»(/cadillac/escalade/gmt400-1998-2000/remont/starter/#starting-system__component-locations) table. Connect a test light between starter relay connector terminal A6 and ground. If test light illuminates, go to step 6. If test light does not illuminate, go to next step.
5. Repair open in Red wire between IGN-A (40-amp) fuse connector terminal M6 and starter relay connector terminal A6. Recheck system.
6. Disconnect starter solenoid connector terminal "S" (Purple wire). Connect a self-powered test light between starter relay connector terminal B4 and starter solenoid terminal connector terminal "S" (Purple wire). If test light illuminates, go to step 8. If test light does not illuminate, go to next step.
7. Repair open in Purple wire between starter relay connector terminal B4 and starter solenoid connector terminal "S". Recheck system.
8. Reconnect starter solenoid connector terminal "S" (Purple wire). Connect a self-powered test light between starter relay connector terminal A4 (Black wire) and ground. If test light illuminates, go to step 10. If test light does not illuminate, go to next step.
9. Repair open in Black wire between starter relay connector terminal A4 and ground. Ground connectors are located at engine harness, at generator bracket or near A/C compressor. See «WIRING DIAGRAMS»(/cadillac/escalade/gmt400-1998-2000/remont/starter/#starting-system). Recheck system.
10. Place gear selector in Park position. Connect test light between starter relay connector terminal B6 (Yellow wire) and ground. Turn ignition switch to START position. If test light illuminates, go to next step. If test light does not illuminate, go to step 12.
11. Replace starter relay. Recheck system.
12. Place gear selector in Park position. Disconnect Park Neutral Position (PNP) switch connector C1. Turn ignition switch to START position. Connect a self-powered test light between PNP switch connector C1 terminals "E" (Purple wire) and "G" (Yellow wire). If test light illuminates, go to step 14. If test light does not illuminate, go to next step.
13. Replace PNP switch. Recheck system.
14. Place gear selector in Neutral position. If test light illuminates, go to next step. If test light does not illuminate, go to step 13.
15. Connect a self-powered test light between PNP switch connector C1 terminal "G" (Yellow wire) and starter relay connector terminal B6 (Yellow wire). If test light illuminates, go to step 17. If test light does not illuminate, go to next step.
16. Repair open in Yellow wire between PNP switch connector C1 terminal "G" and starter relay connector terminal B6. Recheck system.
17. Locate in-line Black 48-pin C200 connector, located at steering column harness at base of column. Disconnect Black 48-pin C200 connector and connect test light between connector C200 terminal D5 (Red wire) and ground. (Scheme 3) If test light illuminates, go to step 19. If test light does not illuminate, go to next step.
18. Repair open in Red wire between IGN-A (40-amp) fuse connector terminal M6 and connector C200 terminal D5. Recheck system.
19. Connect a self-powered test light between 48-pin C200 connector terminal D1 (Yellow wire) and PNP switch connector C1 terminal "E" (Purple wire). If test light illuminates, go to next step. If test light does not illuminate, go to step 21.
20. Repair open in Red wire between connector C200 terminal D5 and ignition switch, or open in Yellow wire between connector C200 terminal D1 and ignition switch. If both wires are okay, replace ignition switch and recheck system.
21. Repair open in Yellow wire between connector C200 terminal D1 and CRANK (10-amp) fuse connector terminal D6. Also check for an open in Purple wire between CRANK (10-amp) fuse connector terminal E5 and PNP connector C1 terminal "E". Recheck system.

Scheme 3

1. Remove starter enable relay located in underhood fuse-relay center, near battery. Using DVOM, measure voltage between starter enable relay connector terminal A6 (Red wire) and ground. If battery voltage exists, go to next step. If voltage does not exist, repair open in Red wire between starter enable relay connector terminal A6 and IGN-A (40-amp) fuse connector terminal M6.
2. Using DVOM, check continuity between starter enable relay connector terminal A4 (Black wire) and ground. If continuity exists, go to next step. If continuity does not exist, repair open in Black wire circuit between starter enable relay and ground connection at right front of dash, above blower motor.
3. Place gear selector in Park position. Connect a DVOM between starter enable relay cavities for terminals B6 (Yellow wire) and A4 (Black wire) of underhood fuse-relay center. Turn ignition switch to START position. If battery voltage exists, go to next step. If battery voltage does not exist, go to step 7.
4. Momentarily connect a fused jumper wire across underhood fuse-relay center connector terminal A6 (Red wire) and terminal B4 (Purple wire). If engine cranks, replace starter enable relay and recheck system. If engine does not crank, go to next step.
5. Reconnect starter enable relay. Turn ignition switch to START position. Using DVOM, measure voltage between starter solenoid terminal "S" (Purple wire) and ground. If battery voltage exists, go to next step. If battery voltage does not exist, repair Purple wire between starter enable relay connector terminal B4 and starter solenoid terminal "S".
6. Turn ignition switch to START position. Using DVOM, measure voltage between starter solenoid terminal "S" and starter motor mounting bolts. If battery voltage exists, replace starter. If battery voltage does not exist, clean starter motor mounting bolts, starter motor and mounting surfaces. Retest system.
7. Reconnect starter enable relay. Disconnect Park Neutral Position (PNP) switch connector C2. See «COMPONENT LOCATIONS»(/cadillac/escalade/gmt400-1998-2000/remont/starter/#starting-system__component-locations) table. Turn ignition switch to START position. Using DVOM, measure voltage between PNP switch connector C2 terminal "E" and ground. If battery voltage exists, go to next step. If battery voltage does not exist, go to step 9.
8. Connect fused jumper from PNP switch connector C2 terminal "G" (Yellow wire) and terminal "E" (Purple wire). Turn ignition switch to START position. If engine cranks, replace PNP switch and recheck system. If engine does not crank, check for an open in Yellow wire between PNP switch connector C2 terminal "G" and underhood fuse-relay center connector terminal B6.
9. Locate Black 48-pin C201 connector, located at lower half of steering column. Using DVOM, backprobe connector C201 terminal D1 (Yellow wire). (Scheme 4) Turn ignition switch to START position. Measure voltage between connector C201 terminal D1 (Yellow wire) and ground. If battery voltage exists, check for open in Yellow wire between ignition switch and CRANK (10-amp) fuse connector terminal E5. CRANK (10-amp) fuse is located in instrument panel fuse block. Check CRANK (10-amp) fuse for open. Also check Purple wire between CRANK (10-amp) fuse connector terminal D6 and PNP switch connector C2 terminal "E". If battery voltage does not exist, go to next step.
10. Using DVOM, backprobe connector C201 terminal D5 (Red wire). Measure voltage between connector C201 terminal D5 and ground. If battery voltage exists, replace ignition switch and recheck system. If battery voltage does not exist, check for open in Red wire between ignition switch and IGN-A (40-amp) fuse, located in underhood ruse-relay center

Scheme 4

"P" Series (Commercial Van)

1. Apply parking brake and block the wheels. Place gear selector to Park position. Connect DVOM between starter solenoid connector terminal "S" (Purple wire) and ground. Turn ignition switch to START position. If reading is more than 10 volts, go to next step. If reading is 10 volts or less, go to step 3 .
2. Ensure starter mounting bolts are clean and tight. Remove starter. Clean starter mounting bolts, starter motor and mounting surfaces. Install starter and recheck system. If engine does not start, replace starter.
3. Inspect CRANK (10-amp) fuse. If fuse is okay, go to next step. If fuse is open, locate and repair short to ground as necessary. Replace CRANK (10-amp) fuse.
4. Connect DVOM to power supply terminal for CRANK fuse holder. Turn ignition to START position. If reading indicates battery voltage, go to next step. If reading does not indicate battery voltage, repair open or shorted condition in Yellow wire between CRANK fuse holder and ignition switch. Retest system.
5. Install CRANK (10-amp) fuse. Substitute a known good starter relay. Attempt to start engine. If engine starts, replace starter relay. If engine does not start, install original starter relay and go to next step.
6. If vehicle is equipped with an automatic transmission, go to next step. If vehicle is equipped with a manual transmission, go to step 9 .
7. Attempt to start engine with vehicle in Park position. Attempt to start engine with vehicle in Neutral position. If engine starts in either position, but not in both positions, replace Park Neutral Position (PNP) switch. If engine did not start, go to next step.
8. Connect DVOM between PNP switch Gray connector C1 terminal "E" (Dark Blue/White wire) and ground. Turn ignition to START position. If reading indicates battery voltage, go to step 10 . If reading does not indicate battery voltage, locate and repair open or shorted condition in Dark Blue/White wire between PNP switch and CRANK (10-amp) fuse.
9. Connect DVOM between Clutch Pedal Position (CPP) switch connector Dark Blue/White wire terminal and ground. Turn ignition switch to START position. If reading is about battery voltage, go to next step. If reading did not indicate battery voltage, locate and repair open or shorted condition in Dark Blue/White wire between CPP switch and CRANK (10-amp) fuse.
10. Using DVOM, backprobe between ground and Purple wire terminal for PNP switch Gray connector C1 terminal "G", or CPP switch connector terminal "C". Turn ignition switch to START position. If reading is about battery voltage, go to next step. If reading does not indicate battery voltage, replace PNP or CPP switch. Retest system.
11. Remove starter relay. Connect DVOM between starter relay cavity for relay terminal No. 85 and ground. Turn ignition switch to START position. If reading is about battery voltage, go to next step. If reading does not indicate battery voltage, go to next step.
12. Repair open Purple wire between starter relay connector terminal No. 85 and PNP or CPP switch. Recheck system.
13. Connect a test light between starter relay cavity for terminal No. 86 (Black wire) and ground. If test light illuminates, go to next step. If test light does not illuminate, repair open in Black wire between starter relay connector and ground. Retest system.
14. Connect a test light between starter relay cavity for terminal No. 30 (Red wire) and ground. If test light illuminates, go to next step. If test light does not illuminate, repair open in Red wire between starter relay connector and battery. Recheck system.
15. Repair open Purple wire between starter relay connector terminal No. 8.

1. Connect a DVOM between starter solenoid connector terminal "S" (Purple wire) and engine ground. Place gear selector in Park (A/T), or depress and hold clutch pedal (M/T). Turn ignition switch to START position and observe DVOM. If reading is 12 volts or more, go to step 13. If reading is less than 12 volts, go to next step.
2. Remove starter relay from underhood fuse-relay center. See «COMPONENT LOCATIONS»(/cadillac/escalade/gmt400-1998-2000/remont/starter/#starting-system__component-locations) table. Connect a test light between starter relay socket terminal No. 30 (Red wire) and ground. If test light illuminates, go to next step. If test light does not illuminate, go to step 14.
3. With ignition in START position, connect test light to starter relay cavity for terminal No. 85. If test light illuminates, go to next step. If test light does not illuminate, go to step 15.
4. Connect DVOM between starter relay cavities for starter relay terminals No. 85 and 86. Turn ignition to START position. If reading is greater than 9.5 volts, go to next step. If reading is less than 9.5 volts, go to step 16.
5. Place gear selector in Park (A/T), or depress and hold clutch pedal (M/T). Connect a DVOM between starter relay cavity No. 85 (Purple/White wire) and engine ground. Turn ignition switch to START position. If reading is 9.5 volts or more, go to next step. If reading is less than 9.5 volts, go to step 17.
6. If vehicle is equipped with a manual transmission, go to next step. If vehicle is equipped with an automatic transmission, go to step 9.
7. Disconnect Clutch Pedal Position (CPP) switch connector. Turn ignition switch to START position. Using DVOM, check voltage between CPP switch wiring harness connector cavity "A" (Purple wire) and ground. If reading is more than 9.5 volts, go to next step. If reading is 9.5 volts or less, go to step 11.
8. Connect a fused jumper wire across CPP switch wiring harness connector cavities "A" (Purple wire) and "C" (Purple/White wire). Turn ignition switch to START position. If starter cranks engine, go to step 18. If starter does not crank engine, go to step 19.
9. Disconnect Park Neutral Position (PNP) switch connector. Turn ignition switch to START position. Using DVOM, measure voltage between PNP switch wiring harness connector C1 terminal "E" (Purple wire) and ground. If reading is more than 9.5 volts, go to next step. If reading is 9.5 volts or less, go to step 11.
10. Connect a fused jumper wire across PNP switch harness connector cavities "E" (Purple wire) and "G" (Purple/White wire). Turn ignition switch to START position. If starter cranks engine, go to step 20. If starter does not crank engine, go to step 21.
11. Turn ignition switch to START position. Check voltage between ignition switch connector C211 cavity D1 (Yellow wire) and ground. (Scheme 3) If reading is more than 9.5 volts, go to step 22. If reading is 9.5 volts or less, go to next step.
12. Check voltage between ignition switch connector C211 cavity D5 (Orange wire) and ground. If reading is more than 9.5 volts, go to step 23. If reading is 9.5 volts or less, go to step 24.
13. Clean starter motor mounting bolts, starter motor and mounting surface, and repeat test. If starter still does not operate, replace starter.
14. Repair open in Red wire between starter relay and IGN A (40-amp) fuse in underhood fuse-relay center. Reinstall starter relay. Recheck system.
15. Repair open in Purple wire between starter relay cavity No. 85 and starter solenoid. Reinstall starter relay. Recheck system.
16. Repair open in Black wire between starter relay and ground. Reinstall starter relay. Recheck system.
17. Replace starter relay. Recheck system.
18. Adjust CPP switch. Repeat test. If starter does not crank engine, replace CPP switch. Recheck system.
19. Repair open in Purple wire between starter relay and CPP switch. Recheck system.
20. Replace PNP switch. Recheck system.
21. Repair open in Purple wire between starter relay and PNP switch. Recheck system.
22. Check for open in Yellow wire between ignition switch and underhood fuse-relay center connector C1 terminal D3. Repair as needed. If circuit is okay, repair open in Purple wire between underhood fuse-relay center connector C1 terminal C3 and CPP switch terminal "A" (M/T), or PNP switch connector terminal "E" (A/T). Recheck system.
23. Replace ignition switch. Recheck system.
24. Repair open in Orange wire between ignition switch and underhood fuse-relay center. Recheck system.

1. Place gear selector in Park position. Turn ignition switch to START position. Using DVOM, measure voltage between starter solenoid terminal "S" (Purple wire) and ground. If reading is about 9.5 volts, go to next step. If reading is not as specified, go to step 5.
2. Disconnect Park Neutral Position (PNP) switch harness connector. See «COMPONENT LOCATIONS»(/cadillac/escalade/gmt400-1998-2000/remont/starter/#starting-system__component-locations) table. Turn ignition switch to START position. Using DVOM, measure voltage between PNP switch connector C1 terminal "G" (Yellow wire) and ground. (Scheme 5) If reading is about 9.5 volts, go to next step. If reading is not as specified, go to step 6
3. Locate Black 48-pin C201 connector, located between instrument panel wiring harness and steering column wiring harness, mounted near base of steering column. Using DVOM, measure voltage between Black 48-pin connector terminal D5 (Red wire) and ground. (Scheme 4) If reading is about 9.5 volts, go to next step. If reading is not as specified, go to step 7.
4. Check for an open or poor connection in Red wire between IGN MAIN 1 (40-amp) fuse in underhood electrical center and ignition switch. Repair as necessary and recheck system. If no problem is found, replace underhood electrical center and recheck system.
5. Connect remote starter switch between starter solenoid terminal "S" (Purple wire) and positive battery terminal. Crank engine. If starter cranks, repair high resistance or poor connection in Black wire between positive battery terminal and starter terminal "B", and/or between positive battery terminal and underhood electrical center. Recheck system. If starter does not crank, replace starter and recheck system.
6. Check for open or high resistance in Purple wire between Park Neutral Position (PNP) switch connector C1 terminal "E" and starter solenoid terminal "S". Repair as necessary and recheck system. If no problem is found, adjust or replace PNP switch and recheck system.
7. Check for high resistance, open or poor connection in Yellow wire between ignition switch and PNP switch connector C1 terminal "G". Repair as necessary and recheck system. If no problem is found, replace ignition switch and recheck system.

Scheme 5

"C", "K" & "P" Series

1. On "C" and "K" diesel models, remove fuel pump relay, located in underhood fuse-relay center. On "C" and "K" gasoline models, disconnect ignition coil connector, located on right rear side of engine. On "P" diesel models, disconnect fuel injection pump fuel shut off solenoid connector, located on engine, in front of throttle body. On "P" gasoline models, disconnect ignition coil connector, located on bracket at rear of intake plenum.
2. On all models, connect DVOM between battery positive and negative terminals. Turn ignition switch to START position for 15 seconds. If reading is greater than 9.6 volts, go to next step. If reading is 9.6 volts or less, perform battery load test. If battery fails load test, replace battery. If battery passes load test, replace starter motor.
3. Connect a DVOM between negative battery terminal and engine block. Turn ignition switch to START position. If reading is less than .5 volt, go to next step. If reading is .5 volt or more, replace battery negative cable and recheck system.
4. Connect DVOM between battery positive terminal and starter solenoid terminal "B". Turn ignition switch to START position. If reading is less than .5 volt, replace starter motor. If reading is .5 volt or more, replace battery positive cable and recheck system.

1. On diesel engines, disconnect fuel shutoff valve solenoid connector. On gasoline engines, disconnect ignition coil connector, located at top right side of engine. On all models, connect a DVOM between battery positive and negative terminals. Turn ignition switch to START position for 15 seconds. If reading is greater than 9.6 volts, go to next step. If reading is 9.6 volts or less, perform battery load test. If battery fails load test, replace battery. If battery passes load test, replace starter motor.
2. Disconnect Black negative battery cable terminal from right engine compartment, near negative battery post. Connect DVOM between battery negative terminal and negative battery cable ground terminal connection, located at left engine compartment, near fender well. Turn ignition switch to START position for 15 seconds. If reading is .5 volt or less, go to next step. If reading is more than .5 volt, check for high resistance between negative battery terminal and negative battery cable ground connection. Repair as necessary and recheck system.
3. Reconnect Black negative battery cable from left engine compartment, near fender well. If vehicle has diesel engine, go to next step. If vehicle has gasoline engine, go to step 5 .
4. On diesel engines, turn ignition switch to START position. Using a DVOM, measure voltage between auxiliary battery negative terminal and ground terminal connection located at left frame rail near auxiliary battery. If reading is .5 volt or less go to next step. If reading is more than .5 volt, check for high resistance in Black negative battery cable between auxiliary battery negative terminal and auxiliary battery negative cable connection, located at left frame rail near auxiliary battery. Recheck system.
5. On gasoline engines, connect DVOM between starter solenoid terminal "B" and battery negative terminal. Turn ignition switch to START position. If reading is more than 9 volts, repair or replace starter. If reading is 9 volts or less, check for open between starter terminal "B" and positive battery terminal. Repair as necessary and recheck system.

1. Connect a DVOM between battery positive and negative terminals. Crank engine for 15 seconds. If reading is greater than 9.5 volts, go to next step. If reading is 9.5 volts or less, perform a battery load test. If battery fails load test, replace battery. If battery passes load test, replace starter motor and recheck system.
2. Connect DVOM between negative battery terminal and engine block (ground). Turn ignition switch to START position while observing DVOM. If reading is less than .5 volt, go to next step. If reading is .5 volt or more, replace battery negative cable and recheck system.
3. Connect DVOM between battery positive terminal and starter solenoid terminal "B" (Black wire). Turn ignition switch to START position. If reading is less than .5 volt while cranking, replace starter motor. If reading is .5 volt or more while cranking engine, replace battery positive cable and recheck system.

1. Connect a DVOM between battery negative and positive terminals. Turn ignition switch to START position and hold for 15 seconds. If reading is more than 9.5 volts, go to next step. If reading is less 9.5 volts or less, perform battery load test. If battery is okay, go to next step. If battery fails load test, replace battery and recheck system.
2. Connect DVOM between battery negative terminal and engine block (ground). Turn ignition switch to START position. If reading is more than .5 volt, replace negative battery cable or connections. Recheck system. If reading is .5 volt or less, go to next step.
3. Connect DVOM between battery positive terminal and starter solenoid terminal "B". Turn ignition switch to START position. If reading is more than .5 volt, replace positive battery cable. If reading is .5 volt or less, clean starter motor mounting blots, starter motor and mounting surface, and repeat test. If starter still does not engage, replace starter and recheck system.

1. Place gear selector in Park position. Connect DVOM between battery positive terminal and starter solenoid terminal "B" (Black wire). Turn ignition switch to START position. If reading is less than .5 volt, go to next step. If reading is .5 volt or more, replace battery positive cable and recheck system.
2. Connect DVOM between negative terminal and battery engine ground connection. Turn ignition switch to START position. If reading is less than .5 volt, go to next step. If reading is .5 volt or more, replace battery negative cable and recheck system.
3. Connect remote starter switch between starter solenoid terminal "S" (Purple wire) and battery positive terminal. Crank starter. If starter cranks, repair high resistance or poor connection in starter circuit. If starter does not crank, replace starter assembly.

PRELIMINARY TESTS

Note. PG260 starter motor is not serviceable, and must be replaced as a complete assembly. If test values do not meet specifications, replace starter and solenoid as an assembly.

Remove starter from vehicle. See STARTER under REMOVAL & INSTALLATION. Check starter for damage such as broken or stripped electrical terminals, broken or cracked drive end housing. If no obvious damage is found, perform starter no-load test and pinion clearance check before disassembling starter motor.

STARTER NO-LOAD TEST

1. Secure starter in vise. Turn carbon pile off and open switch. Connect test equipment to starter as illustrated. (Scheme 6) Turn switch on and adjust carbon pile until voltage is 10 volts. See «STARTER NO-LOAD TEST SPECIFICATIONS»(/cadillac/escalade/gmt400-1998-2000/remont/starter/#starting-system) table. Check ammeter reading and pinion speed on RPM indicator. Turn off carbon pile and open switch. Compare RPM and amperage readings with specifications. See «STARTER NO-LOAD TEST SPECIFICATIONS»(/cadillac/escalade/gmt400-1998-2000/remont/starter/#starting-system) table.
2. If amperage and RPM readings are as specified, starter motor is okay. If test indicates low free speed and/or high current draw, unit may have tight, dirty or worn bearings or bushings, shorted or grounded armature, or a grounded field.
3. High current draw with pinion moving into cranking position but no pinion rotation indicates a direct ground in field, or frozen bearings or bushings. No pinion movement and a normal current reading indicates plunger is unable to move into solenoid or drive is unable to move on armature shaft. No pinion movement and very low or no current draw indicates an open or ground in solenoid windings.
4. Pinion moving into cranking position but not turning and very low current draw indicates an open in field circuit or armature windings, or no current flow between solenoid battery and motor field terminals while motor is engaged. Connect a jumper wire between solenoid battery and motor field terminal "M". If motor now turns at specified RPM, replace solenoid.
5. Low no-load and low current draw indicates high internal resistance due to poor brush lead connections; a dirty commutator; an open in armature windings; broken, worn or weak brush springs; or worn, damaged or dirty brushes. High no-load speed and high current draw indicates shorted field coils or shorted armature windings. If starter vibrates or is noisy, armature may be rubbing against inside of frame and field.

Scheme 6

STARTER NO-LOAD TEST SPECIFICATIONS

SOLENOID WINDINGS TESTS

Note. To prevent overheating, DO NOT allow solenoid pull-in current to flow for more than 15 seconds.

Note. Current flow will decrease as windings heat up.

Hold-In Windings Test

1. If solenoid is not removed from starter motor assembly, disconnect field lead from terminal "M" on solenoid and insulate field lead from solenoid motor terminal. Connect an ammeter and switch in series with 12-volt battery and starter solenoid terminal "S" as illustrated. (Scheme 7) Connect a voltmeter between solenoid terminal "S" and ground. Connect a carbon pile across battery.
2. Turn switch on and quickly adjust carbon pile load until voltage reads as specified. Check ammeter reading. Turn off carbon pile and open switch. On gasoline engines, at 10 volts reading should be 10-20 amps. On diesel engines, at 10 volts reading should be 12-14 amps. If amperage reading is not as specified, replace starter solenoid or starter assembly.

Pull-In Windings Test

Connect test equipment as in hold-in windings test. See HOLD-IN WINDINGS TEST. (Scheme 7) Ground starter solenoid terminal "M". Turn switch on and quickly adjust carbon pile load until voltage reads as specified. Check ammeter reading. Turn off carbon pile and open switch. On gasoline engines, at 10 volts reading should be 60-85 amps. On diesel engines, at 10 volts reading should be 52-59 amps. If ammeter reading is not as specified, replace starter solenoid or starter assembly.

Scheme 7

PINION CLEARANCE CHECK

Note. Pinion clearance is not adjustable. If clearance is not within specification, repair or replace starter.

1. Secure starter motor in vise with opening in housing accessible for measurement. Disconnect field lead at solenoid terminal "M" and insulate from solenoid field terminal "M". Connect battery negative terminal lead to starter frame. Connect 12 volts to starter solenoid terminal "S". Momentarily touch jumper lead from starter solenoid terminal "M" to starter frame, shifting pinion into cranking position.
2. Push pinion as far as possible away from retainer. Using a feeler gauge, ensure there is.010-.160" (.25-4.06 mm) clearance between pinion and retainer. (Scheme 8)

Scheme 8

ARMATURE TEST

Note. Any ball bearings that are removed from armature must be replaced with new bearings.

1. Inspect solder joints between armature windings and commutator bars. If any have come loose, replace armature. If commutator is rough or damaged, replace armature. DO NOT turn commutator in lathe or undercut spaces between bars. If commutator is dirty, clean with fine grit emery cloth and blow away any copper dust.
2. Using growler, check armature for shorts. Hold a flat steel strip on armature parallel to armature core or shaft. Rotate armature in growler. Steel strip will vibrate on area of short circuit.
3. Using self-powered test light, place one lead on armature shaft and other lead on commutator. Test light should not illuminate. If test light illuminates, armature is shorted or grounded and must be replaced.
4. If no-load test indicated armature may be rubbing against inside of frame and field assembly, inspect outside of armature for signs of rubbing. If armature is scored only on one side of laminations, armature shaft may be bent and armature should be replaced. If scoring is all around armature laminations, check frame and field assembly for an out-of-position pole or for a foreign object lodged inside. Repair or replace frame and field assembly.

FIELD COIL OPEN TEST

Remove armature from frame and field assembly. Using self-powered test light, place one lead on field lead connection and other lead on one insulated brush. (Scheme 9) Test light should illuminate. If test light does not illuminate, field coil is open. Replace field and frame assembly. Repeat test for each insulated brush.

Scheme 9

FIELD COIL GROUND TEST

Remove armature from field and frame assembly. On starters with shunt lead, separate field and shunt lead connections during test. Ensure field lead connection is NOT touching ground during test. Using self-powered test light, place one lead on grounded brush holder and other lead on one insulated brush. (Scheme 10) Test light should not illuminate. If test light illuminates, field coil is grounded. Replace field and frame assembly. Repeat test for each insulated brush.

Scheme 10

BRUSHES, SPRINGS & HOLDERS CHECK

If any brushes are damaged (oil-soaked or pitted) or worn more than 90 percent, replace frame and fields. If brushes are not damaged and still have more than 50 percent of brush material left, use a soft cloth to clean contact face of brushes. Check brush spring tension and replace springs if weak, discolored or distorted. Ensure brush holders are clean and brushes are not binding in holders. Ensure full surface of brush contacts commutator for proper performance.

COMMUTATOR END FRAME & BEARING

Replace armature assembly if commutator outer diameter is less than 1.378" (36 mm) or if undercut depth is less than .008" (.2 mm). Do not undercut insulation. Ensure commutator end bearing has not spun in frame. If bearing has spun, replace frame and bearing. Do not lubricate bearing. If bearing is dry or damaged, replace bearing. Measure original bearing depth and install new bearing to same depth.

DRIVE END HOUSING & BEARING

Ensure drive end bearing has not spun in housing. If bearing has spun, replace housing and bearing. Do not lubricate bearing. If bearing is dry or damaged, replace bearing. Measure original bearing depth and install new bearing to same depth.

DRIVE ASSEMBLY CHECK

Check pinion teeth for chips, cracks or excessive wear. If pinion teeth are damaged, replace drive assembly. Also check flywheel for damage. Check drive assembly for slipping before disassembly from armature.

REMOVAL & INSTALLATION

Note. Vehicles are designed for starter mounting without shims. A short shim or long shims may have been added to correct a noise or engagement condition. When installing starter any previously installed shims should be replaced in original location to ensure proper pinion to flywheel clearance.

Removal

1. Disconnect negative battery cable. Raise and support vehicle. Remove starter brackets and shields for solenoid as necessary. Remove as necessary, any transmission covers, inspection plates, transfer case shield, brace rods, or exhaust header pipe and catalytic converter that would interfere with starter removal.
2. On Sierra and Silverado (4.8L, 5.3L & 6.0L), remove front axle mounting bracket through bolt nut. Position the through bolt so it is flush with axle mounting bracket, with out removing the through bolt. Disconnect engine oil level sensor connector and position aside.
3. On "S" & "T" Series (2.2L), remove front exhaust pipe. Remove brace rod from front of engine to clutch housing. Remove brush end bracket-to-engine mounting bolt. If necessary, remove brush end bracket from starter.
4. On all models, remove starter solenoid terminal "S" nut and battery cable nut. Separate wiring from starter solenoid. Remove starter mounting bolts. Remove shims and note arrangement for reassembly. Remove starter.

Installation

To install, reverse removal procedure. Ensure shims are installed in original location. Tighten starter mounting bolts to specification. See TORQUE SPECIFICATIONS .

OVERHAUL

Note. For overhaul, refer to exploded illustration.

STARTER & SOLENOID

Note. PG260 starter motor is not serviceable, and must be replaced as a complete assembly. If test values do not meet specifications, replace starter and solenoid as an assembly.

Scheme 11

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

See also:
• COMPONENT LOCATIONS
• STARTER
• HOLD-IN WINDINGS TEST