Engine Control System - System Testing & Engine Component Tests Cadillac DeVille Concours I final

MODEL IDENTIFICATION

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

MODEL IDENTIFICATION

INTRODUCTION

Before testing separate components or systems, perform all procedures listed in appropriate BASIC DIAGNOSTIC PROCEDURES article. Since many computer-controlled and monitored components will set a Diagnostic Trouble Code (DTC) if they malfunction, it is also recommended self-diagnostics be performed. See appropriate SELF-DIAGNOSTICS article.

Note. Testing individual components does not isolate shorts or opens. Perform all voltage tests with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens.

AIR INDUCTION SYSTEMS

Note. Manufacturer does not provide testing procedures for many individual systems and components. For system and component testing not listed, perform related DTC testing procedure. See appropriate SELF-DIAGNOSTICS article.

Boost Control System Check (3.8L VIN 1)

1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in appropriate SELF-DIAGNOSTICS article. After performing OBD system check, go to next step.
2. Disconnect boost control solenoid harness connector located at left rear of engine, near valve cover. Turn ignition on. Using a test light connected to ground, probe ignition feed circuit at boost control solenoid harness connector. See appropriate wiring diagram in WIRING DIAGRAMS article. If test light illuminates, go to next step. If test light does not illuminate, go to step 11 .
3. Connect test light between boost control solenoid harness connector terminals. If test light illuminates, go to step 14 . If test light does not illuminate, go to next step.
4. Connect scan tool to Data Link connector (DLC). Using scan tool, select OUTPUT TESTS, and then BOOST SOL. Observe test light while commanding boost control solenoid output ON using scan tool. If test light illuminates when solenoid output is commanded ON, go to next step. If test light does not illuminate when solenoid output is commanded ON, go to step 16 .
5. Reconnect boost control solenoid harness connector. Disconnect boost vacuum hose between solenoid and by-pass valve actuator located above boost control solenoid. Connect vacuum gauge to boost control solenoid. Place transmission in Park, start engine and allow engine to idle. Observe vacuum gauge reading. If vacuum does not exist, go to next step. If vacuum exists, go to step 17 .
6. Using scan tool, command boost control solenoid OFF. Observe vacuum gauge reading. If vacuum is greater than 15 in. Hg, go to next step. If vacuum is less than 15 in. Hg, go to step 10 .
7. Check for restriction in boost vacuum hose between boost control solenoid and by-pass valve actuator. If restriction does not exist, go to next step. If restriction exists, repair as necessary and go to step 21 .
8. Reconnect boost vacuum hose between boost control solenoid and by-pass valve actuator. Connect vacuum gauge to read inlet vacuum signal to by-pass valve actuator. Place transmission in Park, start engine and allow engine to idle. Observe vacuum gauge reading. If vacuum is greater than 15 in. Hg, go to «DIAGNOSTIC AIDS»(/cadillac/deville-concours/i-final-1999-1999/remont/testing-diagnostics/#engine-control-system-system-testing-engine-component-tests__diagnostic-aids) . If vacuum is less than 15 in. Hg, go to next step.
9. Repair restriction in inlet vacuum signal hose to by-pass valve actuator or blocked inlet vacuum source. After repairs, go to step 21 .
10. Check for restriction in vacuum hose to boost control solenoid. If restriction does not exist, go to step 18 . If restriction exists, repair as necessary and go to step 21 .
11. Check boost control solenoid ignition feed circuit fuse. If fuse is blown, go to next step. If fuse is okay, go to step 13 .
12. Locate and repair short to ground in ignition feed circuit to boost control solenoid. After repairs, go to step 21 .
13. Locate and repair open in ignition feed circuit to boost control solenoid. After repairs, go to step 21 .
14. Turn ignition off. Disconnect PCM harness connectors. Turn ignition on. Connect test light between boost control solenoid harness connector terminals. If test light illuminates, go to next step. If test light does not illuminate, go to step 20 .
15. Locate and repair short to ground in boost control solenoid control circuit. After repairs, go to step 21 .
16. Turn ignition off. Disconnect PCM harness connector. Turn ignition on. Check boost control solenoid control circuit for an open or short to voltage. If open or short exists, repair as necessary and go to step 21 . If open or short does not exist, go to step 19 .
17. Check for poor terminal connections at boost control solenoid. If problem does not exist, go to next step. If problem exists, repair as necessary and go to step 21 .
18. Replace boost control solenoid. After repairs, go to step 21 .
19. Check boost control solenoid control circuit for a poor terminal connection at PCM. If problem does not exist, go to next step. If problem exists, repair as necessary and go to step 21 .
20. Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
21. Disconnect inlet vacuum signal hose from by-pass valve actuator. Start engine and allow engine to idle. Using scan tool, select OUTPUT TESTS, and then BOOST SOL. Observe MAP sensor reading on scan tool while cycling boost control solenoid ON and OFF. If MAP sensor value decreases while boost control solenoid is commanded ON, and increases while boost solenoid is commanded OFF, system is operating properly. Reconnect inlet vacuum signal hose to by-pass valve actuator. If MAP sensor value is not as specified, go to step 2 .

Diagnostic Aids

If boost control system check has been performed and no electrical or vacuum related fault is noted, check for misadjusted or sticking by-pass valve actuator, or binding by-pass valve or linkage. An intermittent may be caused by a poor connection, rubbed-through wire insulation, or a wire broken inside insulation. Inspect PCM harness connector for backed-out terminals, improper mating, improperly formed or damaged terminals, poor terminal-to-wire connection and damaged harness. To check for intermittent, disconnect PCM and install DVOM to monitor voltage between boost control solenoid control circuit at PCM connector and ground. With ignition on, observe voltage while manipulating related connectors and wiring harness. If failure is induced, voltage display will change. This may indicate location of fault.

MULTI-RAM SYSTEM DIAGNOSIS (3.0L)

Note. Powertrain Control Module (PCM) may also be referred to as Engine Control Module (ECM).

1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in appropriate SELF-DIAGNOSTICS article. After performing OBD system check, go to next step.
2. Connect scan tool to Data Link connector (DLC). Retrieve DTCs. If DTCs P1112 or P1113 are not set, go to next step. If DTC P1112 or P1113 is set, perform appropriate diagnostic test. See appropriate SELF-DIAGNOSTICS article.
3. Visually inspect system. Check for disconnected or damaged vacuum hoses and/or components. Check linkage between vacuum actuators and valves for binding or interference with hoses. Ensure wiring is routed properly and not damaged. If problem does not exist, go to next step. If problem exists, repair as necessary and go to step 14 .
4. Start engine and observe vacuum actuator linkages for switchover valves. Using scan tool, command each valve ON and OFF. If both valves operate, go to next step. If either valve does not operate, go to step 6 .
5. Turn ignition off. Remove duct from between intake resonance switchover valve and throttle body. Hold throttle plates open to view moveable divider in back of intake manifold. Move actuator linkage by hand and ensure divider moves with linkage. Look down passages in intake resonance switchover valve to view moveable divider between 2 sides of valve. Move actuator linkage by hand to ensure divider moves with linkage. If both valves operate properly, system is okay. If either valve does not operate, go to step 13 .
6. Using scan tool, exit device control. Disconnect manifold vacuum supply hose at solenoid valve while observing actuator linkage. If actuator does not move when vacuum is disconnected, go to next step. If actuator moves when vacuum is disconnected, go to step 10 .
7. Check for vacuum at manifold vacuum supply hose. If vacuum exists, go to next step. If vacuum does not exist, go to step 11 .
8. Disconnect other hose from solenoid valve and connect hoses together using suitable vacuum connector. If actuator linkage does not operate, go to next step. If actuator linkage operates, go to step 10 .
9. Disconnect vacuum hose from actuator. If vacuum exists, go to step 13 . If vacuum does not exist, go to step 12 .
10. Replace solenoid valve. After repairs, go to step 14 .
11. Repair vacuum supply hose or plugged vacuum source. After repairs, go to step 14 .
12. Repair vacuum hose to actuator. After repairs, go to step 14 .
13. Replace valve/actuator assembly. After repairs, go to next step.
14. Start engine. Observe vacuum actuator linkages for switchover valves. Using scan tool, command each valve ON and OFF. If both valves operate, system is okay. If either valve does not operate, go to step 2 .

PCM OUTPUT DIAGNOSIS (2.2L & 2.4L)

1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in appropriate SELF-DIAGNOSTICS article. After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. Connect scan tool to Data Link connector (DLC). If a No. 1 is displayed below any of the number output drivers, go to next step. If a No. 1 is not displayed below any of the number output drivers, go to step 4 .
3. Disconnect electrical connector from component related to malfunctioning circuit. If a No. 1 is still displayed below corresponding output driver, go to step 6 . If a No. 1 is not displayed below any of the number output drivers, go to step 9 .
4. Using scan tool, command output being checked while watching corresponding position for that circuit. If that circuits position does not change to a No. 1, go to next step. If that circuits position changes to a No. 1, go to step 7 .
5. If component or function does not operate when commanded, go to step 9 . If component or function operates when commanded, go to step 11 .
6. Turn ignition off. Check for an open, short to voltage or short to ground in any corresponding circuit that indicated a No. 1 below output driver. Repair component or component circuit as necessary and go to step 11 . If circuits are okay, go to step 10 .
7. Disconnect electrical connector from component related to malfunctioning circuit. Using scan tool, command output being checked while watching corresponding position for that circuit. If a No. 1 is still displayed below corresponding output driver, go to next step. If a No. 1 is not displayed below any of the number output drivers, go to step 9 .
8. Turn ignition off. Check for an open, short to voltage or short to ground in any corresponding circuit that indicated a No. 1 below output driver. Repair component or component circuit as necessary and go to step 11 . If circuits are okay, go to step 10 .
9. Diagnose and repair any component that malfunctioned when commanded with scan tool. After repairs, go to step 11 .
10. Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
11. Start engine and operate vehicle under condition under which original symptom was noted. If system does not operate properly, go to step 2 . If system operates properly, go to «DIAGNOSTIC AIDS»(/cadillac/deville-concours/i-final-1999-1999/remont/testing-diagnostics/#engine-control-system-system-testing-engine-component-tests) .

Scan tool has the ability to command certain components and functions ON and OFF. If a component or function does not have this capability, operate vehicle during normal function criteria to check for an open or shorted circuit. An open or short to ground will appear in the open positions of the scan tool only when it is not commanded by the PCM or scan tool. A short to voltage will appear in the short positions on the scan tool only while the component is being commanded by the PCM or scan tool.

PCM POWER & GROUND CHECK

Note. To identify circuits referenced in the following ground and power tests, see appropriate wiring diagram in WIRING DIAGRAMS article.

Ground Circuits

1. Using an ohmmeter, check for continuity to ground at PCM ground terminals. See «POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION»(/cadillac/deville-concours/i-final-1999-1999/remont/testing-diagnostics/#engine-control-system-system-testing-engine-component-tests). (Scheme 3) Resistance should be zero ohms. If resistance is not zero ohms, repair open in ground circuit.
2. Connect negative lead of voltmeter to a known good ground. Backprobe positive lead of voltmeter to each PCM ground terminal. With vehicle running, voltmeter should indicate less than one volt. If voltmeter reading is greater than one volt, check for open, short to voltage, corrosion or loose connection in ground circuit.

Power Circuits

1. Using a voltmeter, check for battery voltage between PCM continuous power terminal(s) and ground. See «POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION»(/cadillac/deville-concours/i-final-1999-1999/remont/testing-diagnostics/#engine-control-system-system-testing-engine-component-tests). (Scheme 3) If battery voltage is not present, check for blown fuse or open fusible link. If fuse or fusible link is okay, check for open in circuit between PCM continuous power terminal and power source.
2. Turn ignition switch to RUN position. Using a voltmeter, check for battery voltage between PCM ignition power terminals and ground. If battery voltage is not present, check IGN fuse. If fuse is okay, check for an open in circuit between battery and ignition switch, and between ignition switch and PCM ignition power terminal. If circuits are okay, check for a defective ignition switch.
3. Connect voltmeter between ground and PCM starter (crank) signal terminal. On vehicles with manual transmission/transaxle, depress clutch pedal. On vehicles with automatic transmission/transaxle, place gear shift lever in Park. On all vehicles, turn ignition switch to START position. Battery voltage should be present only when ignition switch is in START position.
4. If voltage is not present, check CRANK fuse or fusible link between ignition switch and PCM starter (crank) signal terminal. If fuse or fusible link is okay, check for an open in circuit between ignition switch and PCM starter (crank) signal terminal, or check for a defective ignition switch.

PCM Harness Resistance

Turn ignition switch to LOCK position. Disconnect PCM and related component harness connectors. Check for open or short circuits between PCM harness connector terminal and component harness connector terminal. See POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION. (Scheme 3) See appropriate wiring diagram in WIRING DIAGRAMS article. If harness is open or shorted, repair as necessary.

Scheme 3

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION (2.2L & 2.4L)

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION (2.2L & 2.4L) (1)

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION (3.1L - CENTURY)

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION (3.1L - CENTURY) (1)

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION (3.1L - CUTLASS & MALIBU)

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION (3.1L - CUTLASS & MALIBU) (1)

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION (3.1L - GRAND PRIX, LUMINA & MONTE CARLO)

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION (3.1L - GRAND PRIX, LUMINA & MONTE CARLO) (1)

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION (3.4L - ALERO & GRAND AM)

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION (3.4L - ALERO & GRAND AM) (1)

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION (3.5L - INTRIGUE)

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION (3.5L - INTRIGUE) (1)

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION (3.8L - BONNEVILLE, EIGHTY EIGHT, LE SABRE & RIVIERA)

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION (3.8L - BONNEVILLE, EIGHTY EIGHT, LE SABRE & RIVIERA) (1)

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION (3.8L - CAMARO & FIREBIRD)

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION (3.8L - CAMARO & FIREBIRD) (1)

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION (3.8L - PARK AVENUE & REGAL)

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION (3.8L - PARK AVENUE & REGAL) (1)

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION (3.8L - GRAND PRIX, LUMINA & MONTE CARLO)

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION (3.8L - GRAND PRIX, LUMINA & MONTE CARLO) (1)

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION (3.8L - INTRIGUE)

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION (3.8L - INTRIGUE) (1)

POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION (4.0L - AURORA)