Engine Controls - Basic Testing: Diagnosis Isuzu Amigo II

VISUAL INSPECTION

Visually inspect all electrical wiring, looking for chafed, stretched, cut or pinched wiring. Check for any blown fuses. Ensure electrical connectors fit tightly and are not corroded. Ensure vacuum hoses are properly routed and not pinched or cut. See VACUUM DIAGRAMS article to verify routing and connections (if necessary). Inspect air induction system for possible vacuum leaks.

FUEL PUMP PRESSURE TEST

Note. Begin basic fuel system diagnosis with testing fuel pressure.

1. Turn ignition off. Ensure A/C is off (if equipped). Release fuel system pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-16362-S34788331672001010800000). Attach Fuel Pressure Gauge Set (J-34730-1 ) to fuel rail or fuel supply line. (Scheme 1) Turn ignition on. Allow fuel pump to run for about 2 seconds. Check fuel pressure. See «FUEL PUMP PERFORMANCE»(ref-16362-S13845634842001010800000).
2. With engine at normal operating temperature, turn ignition on and let fuel pressure build to maximum pressure. Start engine and observe pressure. See «FUEL PUMP PERFORMANCE»(ref-16362-S13845634842001010800000). If pressure drop is as specified, system is operating properly. If pressure does not drop as specified, see appropriate «FUEL SYSTEM DIAGNOSIS»(ref-16362-S33383929702001010800000) procedure. Locate and repair leak or restriction in fuel system.

FUEL PUMP PERFORMANCE

Scheme 1

TROUBLE SHOOTING - AMIGO, RODEO & PASSPORT 2.2L

Note. To reprogram EEPROM or to program PCM after it has been replaced, special equipment from manufacturer is required.

Note. To identify component terminals and wire colors, see appropriate wiring diagram in WIRING DIAGRAMS article.

Note. Perform all voltage tests with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm impedance. Unless stated otherwise in test procedure.

FUEL SYSTEM ELECTRICAL TEST

1. Perform On-Board Diagnostic II (OBD-II) System Check. See ON-BOARD DIAGNOSTIC II (OBD-II) SYSTEM CHECK in «TESTS W/CODES - INTRODUCTION»(ref-16364) article. After performing OBD-II system check, go to next step.
2. Relieve fuel pressure. Install fuel pressure tester to fuel inlet line test fitting. Using Tech 2 scan tool, command fuel pump on. Fuel pressure should build up immediately. If fuel pressure built up immediately, go to next step. If fuel pressure did not build up, go to step 4).
3. Verify fuel pump is not running by removing gas cap and listening for fuel pump motor. Using scan tool, command fuel pump on. If fuel pump runs for 2 seconds and turns off, fuel electrical system is operating properly. Test is complete. If fuel pump does not run or runs continuously, go to step 12).
4. Turn ignition off. Remove fuel pump relay from fuse/relay box located in engine compartment. Using a test light connected to ground, probe battery feed circuit at fuel pump relay harness connector Pink/White wire terminal. If test light illuminates, go to step 6). If test light does not illuminate, go to next step.
5. Repair open or short in Pink/White wire between fuel pump relay and fuse/relay box in engine compartment.
6. Connect a test light between fuel pump relay harness connector Pink/White wire and Black/Blue wire terminals. Turn ignition on. If test light illuminates for 2 seconds then turns off, go to step 12). If test light does not illuminate, go to next step.
7. Using test light connected to negative battery terminal, probe fuel pump relay harness connector Pink/White wire terminal. Turn ignition on. If test light illuminates for 2 seconds then turns off, go to next step. If test light does not illuminate, go to step 9).
8. Repair open in Black/Blue wire between fuel pump relay and ground.
9. Check for open or short in Pink/White wire between fuel pump relay and PCM connector A-38 terminal E13. Repair as necessary. If circuits are okay, go to step 10).
10. Check for poor connections at fuel pump relay. Repair as necessary. If connections are okay, go to step 11).
11. Replace PCM. Verify system is operating properly.
12. If removed, reinstall fuel pump relay. Disconnect fuel pump electrical connector at fuel tank. Using a test light connected to ground, probe fuel pump harness terminal No. 1 (Black/Orange wire). Using scan tool, command fuel pump on. If test light illuminates for 2 seconds, go to step 15). If test light does not illuminate for 2 seconds, go to next step.
13. Honk horn to verify horn relay is functional. Substitute horn relay for fuel pump relay. Repeat test procedure from step 12). If test light does not illuminate for 2 seconds, go to next step. If test light illuminates for 2 seconds, go to step 17).
14. Check for open or short in Black/Red or Black/Orange wire between fuel pump relay and fuel pump harness connector. Check FUEL PUMP fuse EB-11 (20-amp) located in fuse/relay box in engine compartment. Repair or replace as necessary. Reinstall horn relay.
15. Connect a test light between fuel pump harness terminals No. 1 (Black/Orange wire) and No. 2 (Black wire). Using scan tool, command fuel pump on. If test light illuminates for 2 seconds, go to step 18). If test light does not illuminate for 2 seconds, go to next step.
16. Repair open in Black wire between fuel pump and ground.
17. Replace fuel pump relay. Reinstall horn relay.
18. Replace fuel pump. Retest system.

FUEL SYSTEM DIAGNOSIS

1. Perform On-Board Diagnostic II (OBD-II) System Check. See ON-BOARD DIAGNOSTIC II (OBD-II) SYSTEM CHECK in «TESTS W/CODES - INTRODUCTION»(ref-16364) article. After performing OBD-II system check, go to next step.
2. Turn ignition off. Turn A/C system off. Relieve fuel system pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-16362-S34788331672001010800000) under FUEL SYSTEM. Install Fuel Pressure Gauge (J-34730-1). Turn ignition on. Fuel pump should run for 2 seconds (it may be necessary to turn ignition on several times to obtain highest possible fuel pressure). If fuel pressure is 42-55 psi (3.0-3.9 kg/cm 2 ), go to next step. If fuel pressure is not 42-55 psi (3.0-3.9 kg/cm 2 ), go to step 17).
3. After fuel pump has shut off, fuel pressure should stabilize and remain constant. If fuel pressure remains constant, go to next step. If fuel pressure does not remain constant, go to step 12).
4. With vehicle at normal operating temperature, turn ignition on. Allow fuel pressure to build (it may be necessary to turn ignition on several times to obtain highest possible fuel pressure). Start engine. If fuel pressure drops 3-15 psi (0.2-1.0 kg/cm 2 ), go to next step. If fuel pressure does not drop 3-15 psi (0.2-1.0 kg/cm 2 ), go to step 9).
5. If fuel pressure is suspected of dropping off during acceleration, cruise or hard cornering, go to next step. If fuel pressure is okay, check for improper fuel.
6. Inspect fuel filter and fuel supply line. If no restriction is found, go to next step. If restriction is found, repair as necessary.
7. Remove fuel tank. Inspect fuel pump strainer for a restriction. Check fuel line for leaks. Verify correct fuel pump is installed. If no problem is found, go to next step. If a problem is found, repair as necessary.
8. Replace fuel pump. Verify system is operating properly.
9. Disconnect vacuum hose to fuel pressure regulator. With engine at idle, apply 12-14 in. Hg of vacuum to fuel pressure regulator. If fuel pressure drops 3-15 psi (0.2-1.0 kg/cm 2 ), go to next step. If fuel pressure does not drop 3-15 psi (0.2-1.0 kg/cm 2 ), go to step 11).
10. Locate and repair loss of vacuum to fuel pressure regulator. See «VACUUM DIAGRAMS»(ref-16361) article. Verify system is operating properly.
11. Replace fuel pressure regulator. Verify the system is operating properly.
12. Using scan tool, operate fuel pump sufficiently to pressurize fuel system. When pressure has built, turn fuel pump off. Using locking pliers, pinch fuel supply hose. If fuel pressure remains constant and does not drop, go to next step. If fuel pressure does not remain constant, go to step 15).
13. Check fuel supply line for leaks. Repair as necessary. If no problem was found, go to next step.
14. Remove fuel tank. Check for leaks in hose or in-tank fuel line. Repair as necessary. If no leaks are found, go to step 8).
15. Remove locking pliers from fuel supply hose. Using scan tool, operate fuel pump sufficiently to pressurize fuel system. Using locking pliers, pinch fuel return line. If fuel pressure does not remain constant, go to next step. If fuel pressure remains constant, go to step 11).
16. Locate and replace leaking fuel injector(s). Verify system is operating properly.
17. If fuel pressure is greater than 55 psi (3.9 kg/cm 2 ), go to next step. If fuel pressure is not greater than 55 psi (3.9 kg/cm 2 ), go to step 21).
18. Relieve fuel system pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-16362-S34788331672001010800000) under FUEL SYSTEM. Disconnect fuel return line from fuel rail. Connect a flexible hose to fuel rail return outlet passage, and place open end of hose into approved gasoline container. Turn ignition off for about 10 seconds. Turn ignition on. While fuel pump is running, observe fuel gauge. If fuel pressure is 42-55 psi (3.0-3.9 kg/cm 2 ), go to next step. If fuel pressure is not 42-55 psi (3.0-3.9 kg/cm 2 ), go to step 20).
19. Repair restriction in fuel return line. Verify system is operating properly.
20. Check for restriction in fuel rail outlet passages. Repair as necessary. If there is no restriction, go to step 11).
21. If any fuel pressure exists, go to next step. If no fuel pressure exists, go to step 23). CAUTION: In the next step, DO NOT allow fuel pressure to exceed 60 psi (4.2 kg/cm 2 ), or fuel pressure regulator or fuel pressure gauge may be damaged.
22. Using scan tool, pressurize fuel system. Using pliers, gradually pinch fuel return hose. If fuel pressure is greater than 55 psi (3.9 kg/cm 2 ), go to step 11). If fuel pressure is not greater than 55 psi (3.9 kg/cm 2 ), go to step 7).
23. Using scan tool, command fuel pump ON. Remove gas cap, and listen for sound of fuel pump. If fuel pump is running, go to step 7). If fuel pump is not running, go to «FUEL SYSTEM ELECTRICAL TEST»(ref-16362-S40688053162001010800000) .

TROUBLE SHOOTING - AMIGO & RODEO 3.2L

Note. If PCM requires replacement, PCM must be reprogrammed using a Tech 2 or other OBD II compatible scan tool. Some models may require additional equipment to program EEPROM. For PCM harness connector and terminal identification, see PIN VOLTAGE CHARTS or WIRING DIAGRAMS article.

1. Perform On-Board Diagnostic II (OBD-II) System Check. See ON-BOARD DIAGNOSTIC II (OBD-II) SYSTEM CHECK in «TESTS W/CODES - INTRODUCTION»(ref-16364) article. After performing OBD-II system check, go to next step.
2. Install fuel pressure tester to fuel inlet line test fitting. Using scan tool, command fuel pump on. Fuel pressure should build up immediately. If fuel pressure built up immediately, go to next step. If fuel pressure did not build up, go to step 4).
3. Verify fuel pump is not running by removing gas cap and listening for fuel pump motor. Using scan tool, command fuel pump on. If fuel pump runs for 2 seconds and turns off, fuel electrical system is operating properly. Test is complete. If fuel pump does not run or runs continuously, go to step 12).
4. Turn ignition off. Remove fuel pump relay from fuse/relay box located in engine compartment. Using a test light connected to ground, probe battery feed circuit at fuel pump relay harness terminal No. 5 (White/Black wire). If test light illuminates, go to step 6). If test light does not illuminate, go to next step.
5. Repair open or short in White/Black wire between fuel pump relay and fuse/relay box in engine compartment.
6. Connect a test light between fuel pump relay harness terminals No. 4 (Pink/White wire) and No. 2 (Black wire). Turn ignition on. If test light illuminates for 2 seconds then turns off, go to step 12). If test light does not illuminate, go to next step.
7. Using test light connected to negative battery terminal, probe fuel pump relay connector terminal No. 4 (Pink/White wire). Turn ignition on. If test light illuminates for 2 seconds then turns off, go to next step. If test light does not illuminate, go to step 9).
8. Repair open in Black wire between fuel pump relay and ground.
9. Check for open or short in Pink/White wire between fuel pump relay and PCM harness connector A-38 terminal E13. Repair as necessary. If circuits are okay, go to step 10).
10. Check for poor connections at fuel pump relay. Repair as necessary. If connections are okay, go to step 11).
11. Replace PCM. Verify system is operating properly.
12. If removed, reinstall fuel pump relay. Disconnect fuel pump electrical connector at fuel tank. Using a test light connected to ground, probe fuel pump harness connector terminal No. 2 (Black/Orange wire). Using scan tool, command fuel pump on. If test light illuminates for 2 seconds, go to step 15). If test light does not illuminate for 2 seconds, go to next step.
13. Honk horn to verify horn relay is functional. Substitute horn relay for fuel pump relay. Repeat test procedure from step 12). If test light does not illuminate for 2 seconds, go to next step. If test light illuminates for 2 seconds, go to step 17).
14. Check for open or short in Black/Red or Black/Orange wire between fuel pump relay and fuel pump connector at fuel tank. Check for blown FUEL PUMP fuse EB-11 (20-amp) located in fuse/relay box in engine compartment. Repair or replace as necessary. Reinstall horn relay.
15. Connect a test light between fuel pump harness connector terminals No. 2 (Black/Orange wire) and No. 1 (Black wire). Using scan tool, command fuel pump on. If test light illuminates for 2 seconds, go to step 18). If test light does not illuminate for 2 seconds, go to next step.
16. Repair open in Black wire between fuel pump and ground.
17. Replace fuel pump relay. Reinstall horn relay.
18. Replace fuel pump.

1. Perform On-Board Diagnostic II (OBD-II) System Check. See ON-BOARD DIAGNOSTIC II (OBD-II) SYSTEM CHECK in «TESTS W/CODES - INTRODUCTION»(ref-16364) article. After performing OBD-II system check, go to next step.
2. Turn ignition off. Turn A/C system off. Relieve fuel system pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-16362-S34788331672001010800000) under FUEL SYSTEM. Install Fuel Pressure Gauge (J-34730-1). Turn ignition on. Fuel pump should run for 2 seconds (it may be necessary to turn ignition on several times to obtain highest possible fuel pressure). If fuel pressure is 42-55 psi (3.0-3.9 kg/cm 2 ), go to next step. If fuel pressure is not 42-55 psi (3.0-3.9 kg/cm 2 ), go to step 17).
3. After fuel pump has shut off, fuel pressure should stabilize and remain constant. If fuel pressure remains constant, go to next step. If fuel pressure does not remain constant, go to step 12).
4. With vehicle at normal operating temperature, turn ignition on. Allow fuel pressure to build (it may be necessary to turn ignition on several times to obtain highest possible fuel pressure). Start engine. If fuel pressure drops 3-15 psi (0.2-1.0 kg/cm 2 ), go to next step. If fuel pressure does not drop 3-15 psi (0.2-1.0 kg/cm 2 ), go to step 9).
5. If fuel pressure is suspected of dropping off during acceleration, cruise or hard cornering, go to next step. If fuel pressure is okay, system is okay. Check for improper fuel.
6. Inspect fuel filter and fuel supply line. If no restriction is found, go to next step. If restriction is found, repair as necessary.
7. Remove fuel tank. Inspect fuel pump strainer for a restriction. Check fuel line for leaks. Verify correct fuel pump is installed. If no problems are found, go to next step. If problems are found, repair as necessary.
8. Replace fuel pump. Verify system is operating properly.
9. Disconnect vacuum hose to fuel pressure regulator. With engine at idle, apply 12-14 in. Hg of vacuum to fuel pressure regulator. If fuel pressure drops 3-15 psi (0.2-1.0 kg/cm 2 ), go to next step. If fuel pressure does not drop 3-15 psi (0.2-1.0 kg/cm 2 ), go to step 11).
10. Locate and repair loss of vacuum to fuel pressure regulator. See «VACUUM DIAGRAMS»(ref-16361) article. Verify system is operating properly.
11. Replace fuel pressure regulator. Verify fuel system is operating properly.
12. Using scan tool, operate fuel pump sufficiently to pressurize fuel system. Using locking pliers, pinch fuel supply hose. If fuel pressure remains constant, go to next step. If fuel pressure does not remain constant, go to step 15).
13. Check fuel supply line for leaks. If problem was found, repair as necessary. If no problem was found, go to next step.
14. Remove fuel tank. Check for leaks in hose or in-tank fuel line. Repair as necessary. If no leaks are found, go to step 8).
15. Remove locking pliers from fuel supply hose. Using scan tool, operate fuel pump sufficiently to pressurize fuel system. Using locking pliers, pinch fuel return line. If fuel pressure does not remain constant, go to next step. If fuel pressure remains constant, go to step 11).
16. Locate and replace leaking fuel injector(s). Verify system is operating properly.
17. If indicated fuel pressure is greater than 55 psi (3.9 kg/cm 2 ), go to next step. If fuel pressure is not greater than 55 psi (3.9 kg/cm 2 ), go to step 21).
18. Relieve fuel system pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-16362-S34788331672001010800000) under FUEL SYSTEM. Disconnect fuel return line from fuel rail. Connect a flexible hose to fuel rail return outlet passage, and place open end of hose into approved gasoline container. Turn ignition off for about 10 seconds. Turn ignition on. While fuel pump is running, observe fuel pressure gauge. If fuel pressure is 42-55 psi (3.0-3.9 kg/cm 2 ), go to next step. If fuel pressure is not 42-55 psi (3.0-3.9 kg/cm 2 ), go to step 20).
19. Repair restriction in fuel return line. Verify system is operating properly.
20. Check for restriction in fuel rail outlet passages. Repair as necessary. If there is no restriction, go to step 11).
21. If fuel pressure is present, go to next step. If no fuel pressure is present, go to step 23). CAUTION: In the next step, DO NOT allow fuel pressure to exceed 60 psi (4.2 kg/cm 2 ), or fuel pressure regulator or fuel pressure gauge may be damaged.
22. Using scan tool, operate fuel pump sufficiently to pressurize fuel system. Using pliers, gradually pinch fuel return hose. If fuel pressure is greater than 55 psi (3.9 kg/cm 2 ), go to step 11). If fuel pressure is not greater than 55 psi (3.9 kg/cm 2 ), go to step 7).
23. Using scan tool, command fuel pump on. Remove gas cap, and listen for sound of fuel pump. If fuel pump is running, go to step 7). If fuel pump is not running, go to «FUEL SYSTEM ELECTRICAL TEST»(ref-16362-S06945948212001010800000) .

TROUBLE SHOOTING - HOMBRE 2.2L

Note. If PCM requires replacement, PCM must be reprogrammed using a Tech 2 or other OBD II compatible scan tool. Some models may require additional equipment to program EEPROM. For PCM harness connector and terminal identification, see PIN VOLTAGE CHARTS or WIRING DIAGRAMS article.

DLC DIAGNOSIS OR NO SCAN TOOL DATA

1. Perform On-Board Diagnostic II (OBD-II) System Check. See ON-BOARD DIAGNOSTIC (OBD-II) SYSTEM CHECK in «TESTS W/CODES - INTRODUCTION»(ref-16364) article. After performing OBD-II system check, go to next step.
2. Turn ignition on with engine off. Install Tech 2 scan tool. If scan tool is equipped with external power source, ensure power source and ground are okay. If scan tool powers up, go to next step. If scan tool does not power up, go to step 5).
3. Using scan tool, attempt to communicate with other control modules. If scan tool communicates with other control modules, go to step 10). If scan tool does not communicate with other control modules, go to next step.
4. Turn ignition off. Disconnect PCM connectors. Turn ignition on. Using scan tool, attempt to communicate with other control modules. If scan tool communicates with other control modules, go to step 12). If scan tool does not communicate with other control modules, go to step 11).
5. Using a test light connected to ground, probe DLC battery feed circuit (Orange wire). See «WIRING DIAGRAMS»(/isuzu/amigo/ii-1998-2000/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams) article. If test light illuminates, go to next step. If test light does illuminate, go to step 7).
6. Using a test light connected to battery voltage, probe DLC ground circuits (Black and Black/White wires). See «WIRING DIAGRAMS»(/isuzu/amigo/ii-1998-2000/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams) article. If test light illuminates for both ground circuits, go to step 8). If test light does not illuminate for both ground circuits, go to step 9).
7. Repair open or short to ground in DLC battery feed circuit (Orange wire). After repairs, go to step 15).
8. Check DLC for proper terminal tension or excessive resistance. Repair as necessary. After repairs, go to step 15). If terminals are okay, go to step 14).
9. Repair open or poor connections in DLC ground circuits (Black and/or Black/White wires). After repairs, go to step 15).
10. Check for open in class 2 serial data circuit (Yellow wire) between PCM and splice connection. Repair as necessary. After repairs, go to step 15). If circuit is okay, go to step 12).
11. Check for open or short in class 2 serial data circuit (Purple wire) between PCM and DLC. Repair as necessary. After repairs are complete, go to step 15). If circuit is okay, go to step 13).
12. Replace PCM. Program PCM. After repairs, go to step 15).
13. Install scan tool on another vehicle equipped with class 2 serial data and check for proper operation. If scan tool operates properly, diagnose vehicle computer system. If scan tool does not operate properly, go to next step.
14. Scan tool is malfunctioning. Using scan tool operation manual, repair as necessary. After repairs, go to next step.
15. Using scan tool, clear DTC(s). Warm engine to operating temperature. Operate vehicle within conditions required to set DTC. If scan tool indicates diagnostic ran and passed, go to next step. If scan tool does not indicate diagnostic ran and passed, go to step 2).
16. Check if any additional DTC(s) are set. If additional DTC(s) are present, diagnose DTC(s). See «TESTS W/CODES - INTRODUCTION»(ref-16364) article. If no DTC(s) are stored, system is okay.

General Inspection

1. Ensure proper starting procedure is being used. Visually check vacuum hoses for splits, kinks and proper connections as shown on Vehicle Emission Control Information label. Check ignition wires for cracking, hardness and proper connections at both coil pack and spark plugs.
2. Remove spark plugs. Check and replace as necessary. In very cold temperatures, ensure oil is proper viscosity and not contaminated with gasoline.

1. Perform On-Board Diagnostic II (OBD-II) system check. See ON-BOARD DIAGNOSTIC (OBD-II) SYSTEM CHECK in «TESTS W/CODES - INTRODUCTION»(ref-16364) article. After performing OBD-II system check, go to next step.
2. Relieve fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-16362-S34788331672001010800000) . Connect Fuel Pressure Gauge Kit (J-29658-D) to fuel pressure connector. Turn ignition on with engine off. With fuel pump running, fuel pressure should be 41-47 psi (2.9-3.3 kg/cm 2 ). If fuel pressure is as specified, go to next step. If fuel pressure is not as specified, go to step 12).
3. Wait for fuel pump to stop running. Observe fuel pressure after 10 minutes. Fuel pressure should remain within 5 psi (.35 kg/cm 2 ) of specified pressure. If pressure drops more than 5 psi (.35 kg/cm 2 ), go to step 10). If pressure remains within 5 psi (.35 kg/cm 2 ) of specified pressure, go to next step.
4. Relieve fuel pressure until pressure is 10 psi (.7 kg/cm 2 ). Observe fuel pressure after 10 minutes. Fuel pressure should remain within 2 psi (.14 kg/cm 2 ) of specified pressure. If pressure drops more than 2 psi (.14 kg/cm 2 ), go to step 21). If pressure remains within 2 psi (.14 kg/cm 2 ) of specified pressure, go to next step.
5. If fuel pressure is suspected of dropping off during acceleration, cruise or hard cornering, go to next step. If fuel pressure is as specified, go step 8).
6. Inspect fuel filter and fuel supply line. Repair or replace as necessary. After repairs, go to step 23). If fuel filter and fuel supply line are okay, go to next step.
7. Remove fuel sending unit from fuel tank. Inspect fuel pump strainer for restriction, fuel pump flex pipe for leaks, or verify if fuel pump is of right application. Repair or replace as necessary. After repairs, go to step 23). If no problems are found, go to step 20).
8. Start and warm engine to normal operating temperature. Allow engine to idle. Observe fuel pressure gauge. Fuel pressure should drop 3-10 psi (.2-.7 kg/cm 2 ). If fuel pressure drops as specified, see «TESTS W/O CODES»(ref-16365) article. If fuel pressure does not drop as specified, go to next step.
9. Disconnect vacuum hose to fuel pressure regulator. With engine at idle, apply 12-14" Hg vacuum to fuel pressure regulator using a vacuum pump. Fuel pressure should drop 3-10 psi (.2-.7 kg/cm 2 ). If fuel pressure drops specified, go to step 19). If fuel pressure does not drop as specified, go to step 20).
10. Relieve fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-16362-S34788331672001010800000) . Connect fuel bleed hose to pressure gauge. Insert bleed hose into approved gasoline can. Using scan tool, pressurize fuel system. Bleed air out of fuel gauge. Wait for pressure to build up. Pinch fuel return hose. If fuel pressure remains constant, go to step 21). If fuel pressure does not remain constant, go to next step.
11. Using scan tool, pressurize fuel system. Wait for pressure to build up. Close valve in fuel pipe shut-off adapter connected to fuel return hose. If fuel pressure remains constant, go to step 20). If fuel pressure does not remain constant, go to step 22).
12. If fuel pressure is greater than 47 psi (3.3 kg/cm 2 ), go to next step. If fuel pressure is less than 47 psi (3.3 kg/cm 2 ), go to step 15).
13. Relieve fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-16362-S34788331672001010800000) . Disconnect fuel return line from fuel rail. Attach a piece of fuel hose to return line and place in an approved gasoline container. Turn ignition off for about 10 seconds. Turn ignition on. Observe fuel pressure with fuel pump operating. Fuel pressure should be 41-47 psi (2.9-3.3 kg/cm 2 ). If fuel pressure is as specified, go to step 23). If fuel pressure is not as specified, go to next step.
14. Inspect fuel rail return/outlet passage for restriction. If restriction exists, go to step 24). If restriction does not exist, go to step 20).
15. Recheck fuel pressure. If no fuel pressure exists, go to next step. If fuel pressure exists, go to step 17). CAUTION: DO NOT allow fuel pressure to exceed 65 psi (4.5 kg/cm 2 ).
16. Relieve fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-16362-S34788331672001010800000) . Using scan tool, pressurize fuel system. Bleed air out of fuel gauge. Wait for pressure to build up. Slowly pinch fuel pressure gauge outlet hose. Fuel pressure should be about 47 psi (3.3 kg/cm 2 ). If fuel pressure increases to greater than specification, go to step 20). If fuel pressure does not increase to greater than specification, go to step 7).
17. Check fuel system electrical circuits. See «WIRING DIAGRAMS»(/isuzu/amigo/ii-1998-2000/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams) article. If fuel pump circuit is faulty, go to step 24). If fuel pump circuit is okay, go to next step.
18. Inspect fuel filter for obstruction, fuel supply line for restriction, fuel pump strainer for obstructions or fuel pump flex pipe for leaks. Repair or replace as necessary. After repairs, go to step 24). If problem was not found, go to step 21).
19. Locate and repair vacuum leak to fuel pressure regulator. After repairs, system is okay.
20. Replace fuel pressure regulator. After repairs, system is okay.
21. Replace fuel sending unit. After repairs, system is okay.
22. Locate and replace any leaking fuel injector(s). After repairs, system is okay.
23. Locate and correct restriction in fuel return line. After repairs, system is okay.

TROUBLE SHOOTING - HOMBRE 4.3L

Note. If PCM requires replacement, PCM must be reprogrammed using a Tech 1 or other OBD-II compatible scan tool. Some models may require additional equipment to program EEPROM.

Note. See PIN VOLTAGE CHART S article and WIRING DIAGRAMS articles below, for PCM harness connector, wire terminal and wire color identification.

1. «PIN VOLTAGE CHARTS»(ref-16370)
2. «WIRING DIAGRAMS»(/isuzu/amigo/ii-1998-2000/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams)

1. Perform On-Board Diagnostic II (OBD-II) System Check. See ON-BOARD DIAGNOSTIC (OBD-II) SYSTEM CHECK in «TESTS W/CODES - INTRODUCTION»(ref-16364) article. After performing OBD-II system check, go to next step.
2. Install Tech 2 scan tool on known-good vehicle. If scan tool display VCM data, go to next step. If scan tool does not display VCM data, go to step 17)
3. Reconnect scan tool to vehicle DLC. Turn ignition on. If scan tool powers up, go to next step. If scan tool does not power up with ignition on, go to step 8).
4. Using scan tool, monitor Class II messages. If all modules on serial data circuit communicating, go to next step. If any module(s) on serial data circuit fails to communicate, go to step 6).
5. Using scan tool, check Class II Diagnostic Trouble Codes (DTCs). If any DTCs are stored, diagnose DTC. See «TESTS W/CODES -INTRODUCTION»(ref-16364) article. If no DTCs are stored, check for faulty fuses. Check for loose, corroded or damaged connectors or wiring harness. Repair or replace as necessary and retest system.
6. Check for VCM communication. If VCM is not communicating, go to next step. If no problem is found, see «TESTS W/CODES -INTRODUCTION»(ref-16364) article.
7. Turn ignition off. Disconnect components sharing serial data circuit, leaving VCM harness connectors connected. See «WIRING DIAGRAMS»(/isuzu/amigo/ii-1998-2000/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams) article. Turn ignition on. If scan tool does not display VCM data, go to step 12). If scan tool displays VCM data, problem is intermittent. Check wiring harness and connectors for looseness, damage and corrosion. See «WIRING DIAGRAMS»(/isuzu/amigo/ii-1998-2000/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams) article. Repair or replace as necessary.
8. Using test light connected to ground, probe DLC connector terminal No. 16 (Orange wire). See «WIRING DIAGRAMS»(/isuzu/amigo/ii-1998-2000/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams) article. If test light illuminates, go to next step. If test light does not illuminate, go to step 11).
9. Using test light connected to battery voltage, probe DLC harness connector terminal No. 4 (Black wire). See «WIRING DIAGRAMS»(/isuzu/amigo/ii-1998-2000/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams) article. If test light illuminates, go to next step. If test light does not illuminate, go to step 15).
10. Using test light connected to battery voltage, probe DLC harness connector terminal No. 5 (Black/White wire). See «WIRING DIAGRAMS»(/isuzu/amigo/ii-1998-2000/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams) article. If test light illuminates, go to step 17). If test light does not illuminate, go to step 15).
11. Check PWR AUX fuse in instrument panel fuse box. If fuse is open, go to step 13). If fuse is okay, go to step 14).
12. Inspect class II serial circuits for opens or poor connections. See «WIRING DIAGRAMS»(/isuzu/amigo/ii-1998-2000/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams) article. If problem is found, go to step 16). If no problem is found, go to step 18).
13. Locate and repair short to ground in Orange wire between PWR AUX fuse and DLC. See «WIRING DIAGRAMS»(/isuzu/amigo/ii-1998-2000/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams) article. Replace fuse and go to step 20).
14. Locate and repair open in Orange wire between PWR AUX fuse and DLC. See «WIRING DIAGRAMS»(/isuzu/amigo/ii-1998-2000/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams) article. Replace fuse and go to step 20).
15. Locate and repair open Black wire between DLC and ground. See «WIRING DIAGRAMS»(/isuzu/amigo/ii-1998-2000/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams) article. After repair, go to step 20).
16. Locate and repair opens or poor connections in class II serial data circuits. See «WIRING DIAGRAMS»(/isuzu/amigo/ii-1998-2000/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams) article. After repair, go to step 20).
17. If scan tool does not display VCM data, Scan tool or cables are faulty. See scan tool manual for repair instructions. After repair, go to step 20).
18. Check for poor connections in class II serial data circuit (Dark Green wire) at VCM and DLC harness connectors. See «WIRING DIAGRAMS»(/isuzu/amigo/ii-1998-2000/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams) article. Repair as necessary. If repair was necessary, go to step 20). If no repair was necessary, go to next step.
19. Replace VCM. Program replacement VCM. Perform VDT password learn procedure. Perform CKP sensor variation learn procedure. See «COMPUTER RELEARN PROCEDURES»(ref-12612) article in GENERAL INFORMATION. Retest system.
20. Using scan tool, display CAPTURE INFO. Review CAPTURE INFO functions. If no DTCs are displayed, system is okay. If DTC(s) is displayed, refer to affected DTC to diagnose problem. See «TESTS W/CODES - INTRODUCTION»(ref-16364) article.

1. Ensure proper starting procedure is being used. Visually check vacuum hoses for splits, kinks and proper connections, as shown on Vehicle Emission Control Information label. Check ignition wires for cracking, hardness and proper connections at both coil pack and spark plugs.
2. Remove spark plugs. Check and replace as necessary. In very cold temperatures, ensure oil is proper viscosity and not contaminated with gasoline.

1. Perform On-Board Diagnostic II (OBD-II) System Check. See ON-BOARD DIAGNOSTIC (OBD-II) SYSTEM CHECK in «TESTS W/CODES - INTRODUCTION»(ref-16364) article. After performing OBD-II system check, go to next step.
2. Relieve fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-16362-S34788331672001010800000) under FUEL SYSTEM. Connect Fuel Pressure Gauge (J-34730-1A ) to fuel pressure test port. Turn ignition on with engine off. Fuel pressure should be 60-66 psi (4.2-4.6 kg/cm 2 ) and should hold steady. If fuel pressure is as specified, go to next step. If fuel pressure is not as specified, go to step 8).
3. Turn ignition off for 10 seconds. Ensure A/C is off, if equipped. Turn ignition on. Fuel pump should run for 2 seconds. Observe fuel pressure after pump stops. If pressure is 60-66 psi (4.2-4.6 kg/cm 2 ) and holds steady, go to step 5). If pressure is not within specification, or is within specification but does not hold, go to next step.
4. Relieve fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-16362-S34788331672001010800000) under FUEL SYSTEM. Remove fuel filter and drain fuel from lines into acceptable container. Install 3/8" Fuel Feed Pipe Shut-Off Valve (J42964 ) in place of fuel filter. Ensure valve installation is free of leaks. Idle engine for 30 seconds. Turn ignition off for 10 seconds. Turn ignition on and allow pressure to build. Close shut-off valve and turn ignition off. Pressure should remain constant at 60-66 psi (4.2-4.6 kg/cm 2 ). If fuel pressure is as specified, go to step 12). If fuel pressure is not as specified, go to step 6).
5. If fuel pressure is suspected of dropping off during acceleration, cruise or hard cornering, go to step 27). If fuel pressure is not suspected of dropping during described conditions, go to step 26).
6. Inspect fuel feed line between shut-off valve and fuel rail. If no problem is found, go to next step. If problem is found, go to step 25).
7. Open fuel shut-off valve. Relieve fuel pressure. Drain fuel from lines into approved gasoline container. Install 5/16" Fuel Return Pipe Shut-Off Valve (J42873-2 ) in place of fuel return pipe union at fuel rail. Ensure valve installation is free of leaks. Idle engine for 30 seconds. Turn ignition off for 10 seconds. Turn ignition on and allow pressure to build. Close shut-off valve and turn ignition off. Pressure should remain constant. If fuel pressure remains constant, go to step 22). If fuel pressure does not remain constant, go to step 29).
8. Turn ignition off for 10 seconds. Ensure A/C is off, if equipped. Turn ignition on with engine off. Pump should operate for 2 seconds. If fuel pressure does not exist, go to next step. If fuel pressure exists, go to step 13).
9. Turn ignition off. Install fused jumper wire connected to battery voltage to fuel pump test terminal. See «WIRING DIAGRAMS»(/isuzu/amigo/ii-1998-2000/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams) article. If fuel pump operates, go to next step. If fuel pump does not operate, see «FUEL SYSTEM»(ref-16362-S24725806132001010800000) under ENGINE CRANKS BUT WILL NOT START.
10. Inspect fuel system for restricted fuel lines, plugged fuel filter or clogged fuel pump strainer. If problem was found, go to next step. If no problem was found, go to step 12).
11. Repair or replace components causing fuel system restriction as necessary. Go to step 30).
12. Disconnect negative battery cable. Raise vehicle on hoist. Lower fuel tank sufficiently to disconnect fuel hoses and electrical connectors. Remove fuel tank. Remove and replace fuel tank sender unit module. After repair, go to step 30).
13. Turn ignition off for 10 seconds. Turn ignition on with engine off. Pump should operate for 2 seconds. Monitor fuel pressure. Fuel pressure should be 66 psi (4.6 kg/cm 2 ). If fuel pressure is as specified, go to next step. If fuel pressure is not as specified, go to step 15).
14. Relieve fuel pressure. Disconnect engine compartment fuel return line. Install flex fuel line to return line. Insert other end of flex fuel line into approved container. Turn ignition on and monitor fuel pressure within 2 seconds. Fuel pressure should be 60-66 psi (4.2-4.6 kg/cm 2 ). If fuel pressure is as specified, go to step 16). If fuel pressure is not as specified, go to step 17).
15. Turn ignition off for 10 seconds. Turn ignition on with engine off. Pump should operate for 2 seconds. Monitor fuel pressure Fuel pressure should be 60 psi (4.2 kg/cm 2 ). If fuel pressure is as specified, go to step 19). If fuel pressure is not as specified, go to step 30).
16. Locate and repair restriction in fuel return line. After repair, go to step 30). If no restriction was found, go to next step.
17. Visually and physically inspect fuel return line for restriction where is was disconnected. If restriction was found, go to next step. If no restriction was found, go to step 22).
18. Replace faulty engine fuel lines as necessary. After repair, go to step 30).
19. Check for restricted fuel line or fuel filter. If problem was found, go to next step. If no problem was found, go to step 21).
20. Repair or replace faulty fuel filter and/or fuel line(s) as necessary. After repair, go to step 30) NOTE: DO NOT permit fuel pressure to rise to more than 75 psi (5.3 kg/cm 2 ).
21. Relieve fuel pressure. Drain fuel from lines into acceptable container. Install 5/16" Fuel Return Pipe Shut-Off Valve (J42873-2) in place of fuel return pipe union located near fuel filter. Ensure valve installation is free of leaks. Turn ignition off for 10 seconds. Turn ignition on and bleed air from pressure gauge into approved fuel container. Connect 20-amp fused jumper wire between battery voltage and fuel pump test terminal. See «WIRING DIAGRAMS»(/isuzu/amigo/ii-1998-2000/remont/wiring-diagrams-engine-performance/#engine-performance-wiring-diagrams) article. While monitoring pressure gauge, slowly close shut-off valve on fuel return line. Fuel pressure should be greater than 66 psi (4.6 kg/cm 2 ). If fuel pressure is as specified, go to next step. If fuel pressure is not as specified, go to step 23).
22. Replace fuel pressure regulator. After repair, go to step 30).
23. Check fuel pump for loose or corroded connections, pump motor binding, and poor ground connection. Also check for faulty or incorrect fuel pump. If problem is found, go to next step. If no problem is found, go to step 12).
24. Repair or replace fuel system components as necessary. After repair, go to step 30).
25. Replace faulty fuel feed line and go to step 30).
26. Start engine and let it idle until normal operating temperature is reached. While monitoring fuel pressure, open throttle quickly. Fuel pressure should quickly increase to almost 66 psi (4.6 kg/cm 2 ). If fuel pressure is not as specified, go to next step. If fuel pressure is as specified, fuel system is operating correctly.
27. Inspect fuel system components for leaks or restrictions. Ensure correct fuel pump is installed. If problem is found, go to next step. If no problem is found, go to step 12).
28. Repair or replace faulty fuel system component(s) as necessary. After repair, go to step 30).
29. Locate and replace leaking injector(s). After repair, go to next step.
30. Using scan tool, select CAPTURE INFO, REVIEW INFO function. If additional DTC(s) are stored, diagnose and clear DTC(s). See appropriate «TESTS W/CODES - INTRODUCTION»(ref-16364) article. If DTC(s) are not present, system is okay.

TROUBLE SHOOTING - TROOPER & SLX 3.5L

Note. If PCM requires replacement, PCM must be reprogrammed using a Tech 1 or other OBD-II compatible scan tool. Some models may require additional equipment to program EEPROM.

Note. See PIN VOLTAGE CHARTS and WIRING DIAGRAMS article for PCM harness connector, wire terminal and wire color identification.

1. Perform On-Board Diagnostic II (OBD-II) System Check. See ON-BOARD DIAGNOSTIC II (OBD-II) SYSTEM CHECK in «TESTS W/CODES - INTRODUCTION»(ref-16364) article. After performing OBD-II system check, go to next step.
2. Install fuel pressure tester to fuel inlet line test fitting. Using Tech 2 scan tool, command fuel pump on. Fuel pressure should build up immediately. If fuel pressure builds up immediately, go to next step. If fuel pressure does not build up, go to step 4).
3. Verify fuel pump is not running by removing gas cap and listening for fuel pump motor. Using scan tool, command fuel pump on. If fuel pump runs for 2 seconds and turns off, fuel electrical system is operating properly. Test is complete. If fuel pump does not run or runs continuously, go to step 12).
4. Turn ignition off. Remove fuel pump relay from fuse/relay box located in engine compartment. Using a test light connected to ground, probe battery feed circuit at fuel pump relay harness terminal No. 4 (White wire). If test light illuminates, go to step 6). If test light does not illuminate, go to next step.
5. Repair open or short in White wire between fuel pump relay and fuse/relay box in engine compartment.
6. Connect a test light between fuel pump relay harness terminals No. 1 (Red/White wire) and No. 3 (Black wire). Turn ignition on. If test light illuminates for 2 seconds then turns off, go to step 12). If test light does not illuminate, go to next step.
7. Using test light connected to negative battery terminal, probe fuel pump relay harness terminal No. 1 (Red/White wire). Turn ignition on. If test light illuminates for 2 seconds then turns off, go to next step. If test light does not illuminate, go to step 9).
8. Repair open in Black wire between fuel pump relay and ground.
9. Check for open or short in Red/White wire between fuel pump relay and PCM connector C-3 terminal E13. Repair as necessary. If circuits are okay, go to next step.
10. Check for poor connections at fuel pump relay. Repair as necessary. If connections are okay, go to next step.
11. Replace PCM. Program PCM. Verify system is operating properly.
12. If removed, reinstall fuel pump relay. Disconnect fuel pump electrical connector at fuel tank. Using a test light connected to ground, probe fuel pump harness connector terminal No. 1 (Black/Red wire). Using scan tool, command fuel pump on. If test light illuminates for 2 seconds, go to step 15). If test light does not illuminate for 2 seconds, go to next step.
13. Honk horn to verify horn relay is functional. Substitute horn relay for fuel pump relay. Repeat test procedure from step 12). If test light does not illuminate for 2 seconds, go to next step. If test light illuminates for 2 seconds, go to step 17).
14. Check for open or short in Red or Black/Red wire between fuel pump relay and fuel pump. Check for blown FUEL PUMP fuse F-10 (15-amp) located in fuse/relay box in engine compartment. Repair or replace as necessary. Reinstall horn relay.
15. Connect a test light between fuel pump harness terminals No. 1 (Black/Red wire) and No. 2 (Black wire). Using scan tool, command fuel pump on. If test light illuminates for 2 seconds, go to step 18). If test light does not illuminate for 2 seconds, go to next step.
16. Repair open in Black wire between fuel pump and ground.
17. Replace fuel pump relay. Reinstall horn relay.
18. Replace fuel pump. Retest system.

1. Perform On-Board Diagnostic II (OBD-II) System Check. See ON-BOARD DIAGNOSTIC II (OBD-II) SYSTEM CHECK in «TESTS W/CODES - INTRODUCTION»(ref-16364) article. After performing OBD-II system check, go to next step.
2. Turn ignition off. Turn A/C system off. Relieve fuel system pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-16362-S34788331672001010800000) under FUEL SYSTEM. Install Fuel Pressure Gauge (J-34730-1). Turn ignition on. Fuel pump should run for 2 seconds (it may be necessary to turn ignition on several times to obtain highest possible fuel pressure). If fuel pressure is 42-55 psi (3.0-3.9 kg/cm 2 ), go to next step. If fuel pressure is not 42-55 psi (3.0-3.9 kg/cm 2 ), go to step 17 .
3. After fuel pump has shut off, fuel pressure should stabilize and remain constant. If fuel pressure remains constant, go to next step. If fuel pressure does not remain constant, go to step 12 .
4. With vehicle at normal operating temperature, turn ignition on. Allow fuel pressure to build (it may be necessary to turn ignition on several times to obtain highest possible fuel pressure). Start engine. If fuel pressure drops 3-15 psi (0.2-1.0 kg/cm 2 ), go to next step. If fuel pressure does not drop 3-15 psi (0.2-1.0 kg/cm 2 ), go to step 9 .
5. If fuel pressure is suspected of dropping off during acceleration, cruise or hard cornering, go to next step. If fuel pressure is okay, check for improper fuel.
6. Inspect fuel filter and fuel supply line. If no restriction is found, go to next step. If restriction is found, repair as necessary.
7. Remove fuel tank. Inspect fuel pump strainer for a restriction. Check fuel line for leaks. Verify correct fuel pump is installed in vehicle. If no problem is found, go to next step. If a problem is found, repair as necessary.
8. Replace fuel pump. Verify system is operating properly.
9. Disconnect vacuum hose to fuel pressure regulator. With engine at idle, apply 12-14 in. Hg of vacuum to fuel pressure regulator. If fuel pressure drops 3-15 psi (0.2-1.0 kg/cm 2 ), go to next step. If fuel pressure does not drop 3-15 psi (0.2-1.0 kg/cm 2 ), go to step 11 .
10. Locate and repair loss of vacuum to fuel pressure regulator. See «VACUUM DIAGRAMS»(ref-16361) article. Verify system operation.
11. Replace fuel pressure regulator. Verify fuel system is operating properly.
12. Using Tech 2 scan tool, operate fuel pump sufficiently to pressurize fuel system. Using locking pliers, pinch fuel supply hose. If fuel pressure remains constant, go to next step. If fuel pressure does not remain constant, go to step 15 .
13. Check fuel supply line for leaks. Repair as necessary.
14. Remove fuel tank. Check for leaks in hose or in-tank fuel line. Repair as necessary. If no leaks are found, go to step 8 .
15. Remove locking pliers from fuel supply hose. Using scan tool, operate fuel pump sufficiently to pressurize fuel system. Using locking pliers, pinch fuel return line. If fuel pressure does not remain constant, go to next step. If fuel pressure remains constant, go to step 11 .
16. Locate and replace leaking fuel injector(s). Verify system is operating properly.
17. If fuel pressure is greater than 55 psi (3.9 kg/cm 2 ), go to next step. If fuel pressure is not greater than 55 psi (3.9 kg/cm 2 ), go to step 21 .
18. Relieve fuel system pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-16362-S34788331672001010800000) under FUEL SYSTEM. Disconnect fuel return line from fuel rail. Connect a flexible hose to fuel rail return outlet passage, and place open end of hose into approved gasoline container. Turn ignition off for about 10 seconds. Turn ignition on. While fuel pump is running, observe fuel pressure gauge. If fuel pressure is 42-55 psi (3.0-3.9 kg/cm 2 ), go to next step. If fuel pressure is not 42-55 psi (3.0-3.9 kg/cm 2 ), go to step 20 .
19. Repair restriction in fuel return line. Verify system is operating properly.
20. Check for restriction in fuel rail outlet passages. Repair as necessary. If there is no restriction, go to step 11 .
21. If any fuel pressure exists, go to next step. If fuel pressure does not exist, go to step 23 . CAUTION: In the next step, DO NOT allow fuel pressure to exceed 60 psi (4.2 kg/cm 2 ), or fuel pressure regulator or fuel pressure gauge may be damaged.
22. Using scan tool, operate fuel pump sufficiently to pressurize fuel system. Using pliers, gradually pinch fuel return hose. If fuel pressure is greater than 55 psi (3.9 kg/cm 2 ), go to step 11 . If fuel pressure is not greater than 55 psi (3.9 kg/cm 2 ), go to step 7 .
23. Using scan tool, command fuel pump ON. Remove gas cap, and listen for sound of fuel pump. If fuel pump is running, go to step 7 . If fuel pump is not running, go to «FUEL SYSTEM ELECTRICAL TEST»(ref-16362-S06945948212001010800000) .

See also:
• WIRING DIAGRAMS