Engine Controls - System/component Tests Suzuki Swift II

INTRODUCTION

Before testing separate components or systems, perform procedures in BASIC TESTING article in the ENGINE PERFORMANCE Section. Since many computer-controlled and monitored components set a trouble code if they malfunction, also perform procedures in TESTS W/CODES article in the ENGINE PERFORMANCE Section.

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.

ELECTRONIC CONTROL MODULE (ECM)

Note. For identification of ECM connectors and terminals, see WIRING DIAGRAMS or PIN VOLTAGE CHART S articles in the ENGINE PERFORMANCE Section.

ECM LOCATION

ECM Power Circuits

Turn ignition on. Check for battery voltage between ground and indicated ECM connector terminal. See ECM POWER & GROUND CIRCUITS table. If battery voltage is not indicated, check EFI main relay. See RELAYS & SOLENOIDS.

ECM Ground Circuits

Disconnect ECM connector. Check continuity between ground and indicated ECM connector terminal. See ECM POWER & GROUND CIRCUITS table. If continuity does not exist, repair appropriate wire between ECM connector and ground.

ECM POWER & GROUND CIRCUITS

ECM Circuit Resistance

Make circuit resistance tests with ECM connector disconnected. See CIRCUIT RESISTANCE CHARTS at the end of this article for specifications.

Airflow Meter (DOHC)

1. Turn ignition switch to ON position. Without disconnecting airflow meter connector, move connector seal for access to terminals. Turn ignition on. Using a DVOM with a minimum 10-megohm input impedance, backprobe between White and Red wire terminals of connector.
2. If battery voltage is present, go to next step. If battery voltage is not present, check continuity of White and Red wire circuits between ECM and airflow meter connector.
3. Measure voltage between Black and Red wire terminals of airflow meter connector. If voltage is not 0.2-0.8 volt, check continuity of Black and Red wire circuits between ECM and airflow meter connector.
4. Start engine. Airflow meter voltage signal should increase as engine RPM increases. If airflow meter does not test as described, check airflow meter connections. If connections are okay, replace airflow meter.

Air Temperature Sensor (SOHC)

1. Disconnect air temperature sensor connector. Turn ignition on. Check voltage between Gray wire (SOHC) terminals and ground. If voltage is not 4-5 volts, check sensor resistance or wiring harness for open or short.
2. Remove air temperature sensor and place it in water with a thermometer. Heat water to specified temperature and check resistance. See AIR TEMPERATURE SENSOR RESISTANCE table. Replace air temperature sensor if resistance is not within specification.

AIR TEMPERATURE SENSOR RESISTANCE

Coolant (Water) Temperature Sensor

Remove sensor from intake manifold and place in water with a thermometer. Heat water to specified temperature and check resistance. See COOLANT (WATER) TEMPERATURE SENSOR RESISTANCE table. Replace sensor if resistance is not within specification.

COOLANT (WATER) TEMPERATURE SENSOR RESISTANCE

Crank Angle Sensor

For testing, see CODE 42 in TESTS W/CODES article in the ENGINE PERFORMANCE Section.

Regulated Exhaust Gas Temperature Sensor (DOHC Calif.)

See EXHAUST GAS RECIRCULATION (EGR) under EMISSION SYSTEMS & SUB-SYSTEMS.

Oxygen Sensor

1. Start and warm engine to operating temperature. Pull back seal at oxygen sensor connector. Using a DVOM with at least a 10-megohm input impedance, backprobe oxygen sensor connector.
2. Increase engine speed to 2000 RPM and hold for about one minute while watching voltmeter. Reading should fluctuate between zero and one volt, without being constantly high or low. If voltage is not as specified, see CODE 13 in TESTS W/CODES article in the ENGINE PERFORMANCE Section.

Park/Neutral Switch (A/T)

1. Engine ECM receives Park/Neutral gear selection information from automatic transmission ECM. Disconnect connector at Park/Neutral switch on right side of transmission.
2. With ignition on and transmission in Drive, check voltage on appropriate shift lever switch terminals. See PARK/NEUTRAL SWITCH VOLTAGE table.

PARK/NEUTRAL SWITCH VOLTAGE

Power Steering (P/S) Pressure Switch (SOHC)

1. Disconnect wire connector from P/S pressure switch on P/S pump. Start engine. Connect ohmmeter between ground and switch terminal. With steering wheel in straight-ahead position, there should be no continuity.
2. Turn steering wheel. As steering pressure increases, continuity should exist. If there is no continuity when steering wheel is turned or if there is continuity with steering wheel in straight-ahead position, replace P/S switch.

Power Steering Vacuum Switching Valve (VSV)

1. Turn ignition off. Disconnect power steering VSV connector. Check resistance of VSV at connector terminals. Resistance should be 33-39 ohms. Replace VSV if resistance is not correct. If resistance is okay, remove vacuum hoses from VSV.
2. Blow air into one VSV vacuum fitting. Air should not pass through VSV. If air passes through VSV, replace VSV. Apply battery voltage to VSV connector terminals. Air should pass through VSV. If air does not pass through VSV, replace VSV.

Pressure Sensor (SOHC)

1. Sensor is mounted to right center of firewall. To test pressure sensor on vehicle, turn ignition on. Connect voltmeter between ground and indicated ECM connector terminal (backprobe ECM terminal). See PRESSURE SENSOR OUTPUT VOLTAGE (ON-VEHICLE) table.
2. If voltage is not within specification, see CODE 31 or 32 in TESTS W/CODES article in the ENGINE PERFORMANCE Section. To bench test pressure sensor, see PRESSURE SENSOR OUTPUT VOLTAGE (OFF-VEHICLE) table. If voltage is not within specification, replace pressure sensor.

PRESSURE SENSOR OUTPUT VOLTAGE (ON-VEHICLE)

PRESSURE SENSOR OUTPUT VOLTAGE (OFF-VEHICLE)

Throttle Position Sensor (TPS)

1. Disconnect negative battery cable and TPS connector. (Scheme 75)or (Scheme 76). Using ohmmeter, check resistance between indicated terminals. See THROTTLE POSITION SENSOR (TPS) RESISTANCE table. If resistance is not as specified, adjust TPS.
2. See ADJUSTMENTS article in the ENGINE PERFORMANCE Section. If resistance is not as specified after adjustment, replace TPS. For further diagnostic procedures, see TESTS W/CODES article in the ENGINE PERFORMANCE Section.

THROTTLE POSITION SENSOR (TPS) RESISTANCE (1) (2)

Scheme 75

Scheme 76

Vehicle Speed Sensor (VSS)

1. Disconnect negative battery cable. Remove instrument cluster. Connect ohmmeter between RSW and GND terminals on back of instrument cluster. Insert screwdriver into speedometer cable connector; rotate screwdriver. (Scheme 77)or (Scheme 78).
2. Ohmmeter reading should alternate between zero and infinity 4 times for each revolution of speedometer cable. Replace speedometer if VSS does not test as described.

Scheme 77

Scheme 78

RELAYS & SOLENOIDS

Note. For relay terminal and circuit identification, see WIRING DIAGRAMS article in the ENGINE PERFORMANCE Section.

EFI Main Relay

1. Remove relay from main fuse box in engine compartment, located between battery and left fenderwell. (Scheme 79) Turn ignition on. Check for battery voltage on White/Red wire terminal and Black/White wire terminal of relay connector. Battery voltage should be present.
2. If battery voltage is not present, check White/Red wire and Black/White wire circuits between fuse and relay. Repair as necessary. Turn ignition off. Disconnect negative battery cable. Remove relay from main fuse box. Check for continuity between terminals "A" and "B". (Scheme 80)
3. Continuity should not be present. If continuity exists, replace relay. Measure resistance between terminals "C" and "D". Resistance should be 56-84 ohms. If resistance is not correct, replace relay. Apply battery voltage to terminals "C" and "D". Continuity should be present. If continuity is not present, replace relay.

Fuel Pump Relay

1. Fuel pump relay is constructed the same as EFI main relay and should be checked in same manner. See appropriate EFI MAIN RELAY. (Scheme 79)and (Scheme 80). Turn ignition off. Disconnect negative battery cable. Disconnect relay connector and remove relay. Using an ohmmeter, check continuity between terminals "A" and "B". If continuity is not present, go to next step. If continuity is present, replace relay.
2. Check resistance between terminals "C" and "D". If resistance is 56-84 ohms, go to next step. If resistance is not 56-84 ohms, replace relay.
3. Energize relay by applying battery voltage and ground to terminals "C" and "D". Check continuity between terminals "A" and "B". If continuity is present, relay is okay. If continuity is not present, replace relay.

FUEL PUMP RELAY LOCATION

Scheme 79

Scheme 80

Lock-Up Relay (TBI A/T)

1. Relay is located in relay panel, near right shock tower in engine compartment. Turn ignition on. Check for battery voltage at lock-up relay White/Red and Blue/Black wire terminals. DO NOT depress brake pedal.
2. If no voltage is present, check electrical circuit of each terminal (including brake pedal switch). If voltage is present, connect jumper wire between relay White/Yellow wire terminal and ground. Lock-up relay should operate and battery voltage should be present at relay White wire terminal. Replace lock-up relay if test results are not as specified.

EGR Vacuum Switching Valve (VSV)

See EXHAUST GAS RECIRCULATION (EGR) under EMISSION SYSTEMS & SUB-SYSTEMS.

Canister Purge Vacuum Switching Valve (VSV)

See FUEL EVAPORATION under EMISSION SYSTEMS & SUB-SYSTEMS.

Fuel Injector(s)

See FUEL CONTROL under FUEL SYSTEM.

Idle Speed Control (ISC) Solenoid

See IDLE SPEED CONTROL (ISC) under IDLE CONTROL SYSTEM.

Throttle Opener Vacuum Switching Valve (TBI)

See THROTTLE OPENER SYSTEM (TBI) under IDLE CONTROL SYSTEM.

See FUEL PUMP RELAY under RELAYS.

Fuel Pressure Regulator (Except SOHC)

1. Regulator is mounted to throttle body, or at end of fuel rail closest to distributor (DOHC).
2. Start and idle engine. Disconnect vacuum hose from regulator. If vacuum is present, go to next step. If no vacuum is present, check for blocked hose between regulator and intake manifold.
3. Check fuel pressure with engine running and vacuum hose connected to regulator. Disconnect vacuum hose from fuel pressure regulator. If fuel pressure does not increase, replace fuel pressure regulator.

Note. For fuel system pressure testing and specifications, see BASIC TESTING article in the ENGINE PERFORMANCE Section.

Fuel Pressure Regulator (SOHC)

Regulator is mounted on top of throttle body. If fuel pressure is not within specification, check fuel pump unregulated pressure. If unregulated pressure is within specification, check for clogged vacuum passage between intake manifold and fuel pressure regulator. If passage is clear, replace regulator.

Fuel Pump Circuit Test (DOHC)

1. Turn ignition on. Operating sound of fuel pump should be heard for 3 seconds. If fuel pump operating sound is heard, fuel pump circuit is okay. If fuel pump operating sound is not heard, go to next step.
2. Remove fuel pump relay with connector from main fuse box, located near battery. (Scheme 79) With fuel pump relay connected, ensure voltage exists at White/Blue wire. If voltage does not exist, check EFI main relay. See EFI MAIN RELAY under RELAYS. With ignition on and engine off, install a jumper wire between fuel pump relay Pink and White/Blue wires. Fuel pump should activate.
3. If fuel pump activates, go to next step. If fuel pump does not activate, check fuel pump relay connector for poor connection and fuel pump relay Pink wire for an open. If okay, check for faulty fuel pump. See BASIC TESTING article in the ENGINE PERFORMANCE Section.
4. If fuel pump activates when fuel pump relay is jumpered, check ignition fuse. If ignition fuse is okay, check for faulty fuel pump relay. See FUEL PUMP RELAY under RELAYS. If fuel pump relay is okay, check for open or poor connection between ECM and fuel pump relay Pink/White wire. If wire is okay, substitute a known good ECM and retest.

Fuel Pump Circuit Test (SOHC)

1. With ignition on and engine off, listen for operating sound of fuel pump. Pump should run for 2 seconds after switch is turned on.
2. If operating sound is not heard, go to next step. If operating sound is heard, fuel pump circuit is okay. Check fuel pressure to ensure pump is operating at full volume. See BASIC TESTING article in the ENGINE PERFORMANCE Section.
3. Remove fuel pump relay. See FUEL PUMP RELAY LOCATION table under RELAYS. (Scheme 79) Apply battery voltage to Pink wire terminal (harness side of connector) and ground to body.
4. If pump operates, go to next step. If pump does not operate, check continuity of Pink wire between fuel pump relay and pump (in tank). If continuity exists, replace pump. If continuity does not exist, repair circuit.
5. Turn ignition on. Check for battery voltage on Black/White and White/Blue wire terminals of fuel pump relay connector. If battery voltage is present on both terminals, go to next step. If battery voltage is not present on one or both terminals, check appropriate fuses and feed circuits.
6. Check fuel pump relay. See FUEL PUMP RELAY under RELAYS. If fuel pump relay is okay, check continuity of Pink/White wire between fuel pump relay and ECM connector terminal B10. If circuit is okay, replace ECM.

1. If engine does not run, go to step 3). If engine runs, listen for operational noise from fuel injector(s). Cycling of injectors should increase and decrease with engine speed.
2. On TBI models, if fuel is not injected in a conical-shaped pattern while engine is cranking or running, replace injector. Turn ignition off. If fuel leaks from injector at a rate of more than 1 drop per minute with ignition off, replace injector.
3. On all models, turn ignition off. Disconnect injector connector. Measure resistance across injector terminals. At 68°F (20°C), resistance should be as specified in FUEL INJECTOR RESISTANCE table.

FUEL INJECTOR RESISTANCE

Fuel Injector Resistor (SOHC)

Disconnect 2-wire connector from resistor, mounted on left end of firewall. Check resistance between terminals. If resistance is not 1.9-2.1 ohms, replace resistor.

Note. For fuel system pressure testing and specifications, see BASIC TESTING article in the ENGINE PERFORMANCE Section.

Fuel Injector Circuit Test (DOHC)

1. Crank engine and check operating sound of each fuel injector. If operating sound can be heard from all 4 fuel injectors, fuel injector circuit is okay. If no operating sound at all is heard from any of the fuel injectors, go to next step. If one or more fuel injector(s) makes no operating sound, go to step 6).
2. If no operating sound is heard at all from any of the fuel injectors, turn ignition off. Disconnect ECM 10-pin connector.
3. Using an ohmmeter, check for continuity between ECM 10-pin connector terminals C3 and C8. (Scheme 81) If continuity does not exist, check for open between terminals C3 and C8 or poor connections at fuel injector. Check for continuity between terminal C5 and ground. If continuity does not exist, check C5 wire for open or poor ground.
4. Disconnect ohmmeter. Turn ignition on. Using a voltmeter, check for battery voltage between ECM terminal C2 and ground. If battery voltage is not present, check for open circuit. Check EFI main relay. See EFI MAIN RELAY under RELAYS. If ohmmeter and voltmeter readings are okay, go to next step.
5. If ohmmeter and voltmeter readings are okay, check connections at ECM 10-pin connector terminal C3 to C4, C8 to C9, C5 to C10 and C2 to C7. (Scheme 82) If connections are okay, substitute a known good ECM and retest.
6. If one or more fuel injector(s) makes no operating sound, check each fuel injector connector for poor connection. If okay, check fuel injectors. See FUEL INJECTOR(S) under FUEL CONTROL.

Scheme 81

Scheme 82

Fuel Injector Circuit Test (SOHC)

1. Turn ignition on. If fuel is not injected from injector when ignition is turned on (without cranking engine), go to step 3). If fuel is injected from injector when ignition is turned on (without cranking engine), go to next step.
2. Check for short to ground in Yellow/Black wire between injector and ECM. If wire is okay, check fuel injector and fuel injector resistor. See FUEL INJECTOR(S) and FUEL INJECTOR RESISTOR (SOHC) under FUEL CONTROL. If fuel injector and fuel injector resistor are okay, replace ECM.
3. Crank engine. If fuel is NOT injected during cranking, go to step 4). If fuel is injected during cranking, turn ignition off and check fuel injector for leaks. See FUEL INJECTOR(S) under FUEL CONTROL. If fuel injector leaks, replace fuel injector. If fuel injector does not leak, fuel injector circuit is okay.
4. Listen for operating sound of fuel injector while cranking engine. If operating sound is not heard, go to next step. If operating sound is heard, check fuel pump. See appropriate FUEL PUMP CIRCUIT TEST under FUEL DELIVERY.
5. Turn ignition off. Disconnect fuel injector connector. Check resistance between fuel injector connector terminals. If resistance is 0.5-1.5 ohms at 68°F (20°C), go to step 7). If resistance is not within specification, check for open sub-wires (short section of wires between fuel injector and connector).
6. If sub-wires are okay, check for poor connection at sub-wire connector. If connection is okay, replace fuel injector.
7. Check fuel injector resistor. See FUEL INJECTOR RESISTOR (SOHC) under FUEL CONTROL. Replace fuel injector resistor if not within specification. If fuel injector resistor is okay, turn ignition off. Connect fuel injector and fuel injector resistor connectors.
8. Disconnect 12-pin ECM connector. Turn ignition on. If battery voltage is present on ECM terminal A2, go to next step. If battery voltage is not present, repair open in circuit between EFI main relay and ECM.
9. Check for poor connection at ECM connector terminal A2. If connection is good, replace ECM.

AIR VALVE

DOHC

Air valve is bolted to intake manifold. To check air valve on vehicle, turn engine off. Remove air valve cap at end of air valve. With coolant temperature less than 176°F (80°C), air valve should be open. With temperature greater than 176°F (80°C), air valve should be closed. Install new air valve cap gasket when installing air valve cap.

SOHC

Remove throttle body. See THROTTLE BODY in N - REMOVE/INSTALL/OHAUL article in the ENGINE PERFORMANCE Section. Immerse air valve portion of throttle body in water. Ensure air valve closes gradually as water temperature rises. Air valve should be fully closed at approximately 176°F (80°C).

1. Before idle speed/ISC duty is checked or adjusted, ensure all wires and vacuum hoses are connected securely, accelerator cable has some play, valve clearance and timing are set to specification, and all accessories are turned off.
2. Warm engine to normal operating temperature. Connect tachometer. Using a service wire, connect terminal "D" (ground) and terminal "B" (diagnostic switch). Ensure CHECK ENGINE light indicates a Code 12. Connect duty meter between terminal "D" (ground) and terminal "F" (duty output). If idle speed and ISC duty are not within specification, remove adjusting screw protective cap and adjust idle speed by turning adjusting screw. See ADJUSTMENTS article in the ENGINE PERFORMANCE Section. Replace ISC solenoid if defective. If ISC solenoid is okay, go to next step.
3. If vehicle is equipped with A/C, go to step 4). If vehicle is not equipped with A/C, replace adjusting screw protective cap and remove service wire.
4. Turn A/C on, and set heater blower switch to high (maximum) speed. With A/C working properly, ensure idle speed and ISC duty are within specification. If idle speed and/or ISC duty are not within specification, adjust at A/C Vacuum Switching Valve (VSV). See ADJUSTMENTS article in the ENGINE PERFORMANCE Section. Replace ISC solenoid and/or A/C VSV if defective. Remove service wire. Replace adjusting screw protective cap if removed.

1. Before idle speed/ISC duty is checked or adjusted, ensure all wires and vacuum hoses are connected securely, accelerator cable has some play, valve clearance and timing are set to specification, and all accessories are turned off.
2. Warm engine to normal operating temperature. Connect tachometer. Using a service wire, connect terminal "D" (ground) and terminal "B" (diagnostic switch). Ensure CHECK ENGINE light indicates a Code 12. Connect duty meter between terminal "D" (ground) and terminal "F" (duty output). If idle speed and/or ISC duty are not within specification, adjust by turning idle speed adjusting screw. See ADJUSTMENTS article in the ENGINE PERFORMANCE Section. If idle is too high, go to step 3). If idle is too low, go to step 5). If idle is unchanged (even with headlights on), go to step 7).
3. If idle is too high, and cannot be lowered, pinch ISC solenoid valve hose shut. If engine speed reduces, check ISC solenoid resistance. If ISC solenoid resistance is not 30-33 ohms, replace ISC solenoid. Ensure idle switch and circuit are okay. If Red/White wire from ECM (terminal No. A4) to ISC is not grounded, replace ECM with a known good unit and recheck system.
4. If engine speed does not reduce, ensure air intake system is free from vacuum leaks. If there are no vacuum leaks, adjust duty and idle speed by turning idle speed adjusting screw. See ADJUSTMENTS article in the ENGINE PERFORMANCE Section. If engine speed is still not adjustable, check air valve for proper operation.
5. If idle is too low and cannot be increased, ensure air is being drawn into ISC hose to air cleaner case. If engine speed increases, adjust duty and idle speed. If idle remains unchanged, check ISC solenoid resistance. If ISC solenoid resistance is not 30-33 ohms, replace ISC solenoid.
6. Check for clogged ISC hose, open circuit in Red/White wire or poor connection at ISC solenoid. If okay, replace ECM with a known good unit and recheck system.
7. If idle speed remains unchanged, turn ignition off. Disconnect ECM connector. If resistance between terminals No. A4 and A13 is 30-33 ohms, check connector terminal. If connection is okay, replace ECM with a known good unit and recheck. If resistance reading is not 30-33 ohms, check for poor terminal connection or an open wire in harness. If ECM terminal connection and wire harnesses are okay, replace ISC solenoid.

1. Turn ignition off. Disconnect electrical connector from ISC solenoid.
2. Check resistance between ISC solenoid terminals. Resistance should be 30-33 ohms. On Sidekick (PFI), disconnect ECM connectors and measure resistance between terminals No. B12 and A12. Resistance should be 11-14 ohms. Replace ISC solenoid if defective.
3. If reading is okay, disconnect ISC solenoid air hose from air intake case. It should be difficult to blow air into hose. If resistance is felt, connect battery voltage to ISC solenoid valve terminals. If it is still difficult to blow air through valve, replace ISC solenoid valve. Reinstall hose and connector securely.

TIMING CONTROL SYSTEMS

Note. Ensure increasing engine speed advances ignition timing.

1. Ensure transmission is in Neutral or Park and parking brake is set. Inspect crankshaft pulley timing mark and timing mark indicator on timing belt cover. Clean marks as required. Start engine, and warm it to normal operating temperature. Turn all accessories off. Attach timing light to No. 1 spark plug wire. Ensure idle speed is correct. See IDLE SPEED SPECIFICATIONS table in SPECIFICATIONS article in the ENGINE PERFORMANCE Section. CAUTION: Driving with jumper wire installed in monitor connector will damage catalytic converter.
2. Connect ground terminal "D" and test switch terminal "E" of monitor connector. Aim timing light at crankshaft pulley and timing cover timing marks. If ignition timing is not within specification, loosen distributor hold-down bolt and rotate distributor to obtain correct ignition timing. See IGNITION TIMING table in SPECIFICATIONS article in the ENGINE PERFORMANCE Section. Tighten distributor hold-down bolt, and recheck ignition timing.

Note. With jumper wire installed, timing should be fixed. If timing varies, terminal "D" is not properly grounded.

EXHAUST GAS RECIRCULATION (EGR)

Note. Swift Federal vehicles are not equipped with EGR system.

EGR System Test (Calif.)

1. To check system operation, place transaxle in Park (A/T) or Neutral (M/T). Apply parking brake.
2. With coolant temperature less than 122°F (50°C) on DOHC models, or 104°F (40°C) on SOHC models, start engine and operate at high RPM. EGR valve diaphragm should not retract.
3. Warm engine to normal operating temperature. Operate engine at high RPM. EGR valve diaphragm should retract.
4. If EGR valve does not operate as specified, check for misrouted, restricted, clogged or deteriorated vacuum hoses. If vacuum hoses are okay, check EGR valve and EGR modulator. See EGR VALVE and EGR MODULATOR.
5. If EGR valve and EGR modulator are okay, check EGR Vacuum Switching Valve (VSV). See EGR VACUUM SWITCHING VALVE (VSV).
6. If VSV is okay, check wiring and ECM. ECM will set a Code 51 if EGR system failure is present. See TESTS W/CODES article in the ENGINE PERFORMANCE Section for system diagnosis.
7. To check for clogged EGR passages, allow engine to idle. Manually open EGR valve. Engine RPM should decrease. If engine speed does not decrease, check for clogged EGR passages.

Recirculated Exhaust Gas Temperature Sensor (REGTS) (DOHC Calif.)

1. Sensor is threaded into EGR valve. Disconnect negative battery cable. Disconnect 2-wire connector from sensor and remove sensor. Position sensor threads in container of water with thermometer. Connect ohmmeter leads to sensor terminals.
2. Apply heat to container until water reaches specified temperature. See REGTS RESISTANCE table. Replace sensor if resistance is not within specification.

REGTS RESISTANCE

EGR Valve

1. Disconnect EGR vacuum hose and attach a hand-held vacuum pump to vacuum hose port. Apply approximately 8 in. Hg to EGR valve while checking for smooth operation of diaphragm. Ensure diaphragm maintains position without loosing vacuum.
2. With engine at idle, apply vacuum to EGR diaphragm. Engine should idle rough and/or stall. If diaphragm retracts and engine RPM does not change, remove EGR valve and check for clogged passages.

EGR Modulator

1. For EGR modulator location, see appropriate vacuum diagram in VACUUM DIAGRAMS article in the ENGINE PERFORMANCE Section. Remove upper cap from modulator. Remove filter and clean with compressed air. Reinstall filter and upper cap. Remove EGR modulator.
2. Using low air pressure, apply air to one upper vacuum hose port and plug opposite vacuum hose port. Air should flow freely through filter housing.
3. Connect hand-held vacuum pump to one upper vacuum hose port. Connect vacuum gauge to opposite vacuum hose port. Using low air pressure, apply air to bottom port while applying vacuum with vacuum pump. Vacuum should be indicated on gauge. When low air pressure application stops at bottom port, vacuum gauge indicator should return to zero. Replace EGR modulator if operation is not as specified.

1. Turn ignition off. Disconnect connector from VSV. On DOHC, VSV is mounted behind engine, near center of firewall. On SOHC, VSV is located between distributor and EGR modulator.
2. Turn ignition on and then off. Check resistance between VSV terminals. If resistance is not 30-39 ohms at 68°F (20°C), replace VSV.
3. Disconnect upper and lower hoses from VSV. Connect short section of hose to lower horizontal port of VSV. Blow air through hose connected to VSV. Air should exit through other port, not filter.
4. If air exits through filter, replace solenoid. If air does not exit through filter, energize solenoid by applying battery voltage to appropriate wire terminal and ground to other terminal. See EGR VACUUM SWITCHING VALVE TERMINAL IDENTIFICATION table. Solenoid should click. Blow air through hose connected to solenoid. Air should now exit through filter and not through other port. If test is not as specified, replace solenoid.

EGR VACUUM SWITCHING VALVE TERMINAL ID

Note. For EGR control system vacuum and wiring diagrams, see Figs. 9 and 10.

Scheme 83

Scheme 84

Bimetallic Vacuum Switching Valve

Disconnect vacuum hose from valve, located under intake manifold. Connect a hose to port on valve. Blow through hose. With engine coolant temperature less than 113°F (45°C), air should exit through filter on valve. With engine coolant temperature greater than 140°F (60°C), air should not exit through filter.

Canister Purge Valve

1. Disconnect hoses at purge valve on top of canister. (Scheme 85) Using low air pressure, blow through fuel tank port. Air should exit through air vent. Blow air through purge port. No air should exit and pressure should hold.
2. While applying more than 3.1 in. Hg to throttle body port, blow air through purge port. Air should exit through fuel tank port and air vent. If canister purge valve does not test as specified, replace canister.

Scheme 85

Canister Purge Vacuum Switching Valve (DOHC)

1. Turn ignition off. Using ohmmeter, check resistance between terminals of Vacuum Switching Valve (VSV) connector. If resistance is not 33-39 ohms, replace VSV. Disconnect vacuum hoses from VSV. Connect short section of hose to either port of VSV. Blow through hose. Air should not pass through VSV.
2. Apply battery voltage to White/Blue wire terminal and ground to other wire terminal. Blow through hose. Air should pass through VSV. If VSV does not test as specified, replace VSV.

PCV Valve

Valve is located in intake manifold. Start engine. Remove valve from intake manifold. Place finger over valve. Vacuum should be present. Remove finger from PCV valve. Valve should snap back.

TRANSMISSION

Note. Although the lock-up relay system is not technically an engine performance system, it can affect driveability if it malfunctions.

Circuit Resistance Identification Chart (DOHC). Scheme 86

Scheme 87

Circuit Resistance IdentificationChart (SOHC). Scheme 88

Scheme 89