Engine Controls - System/component Tests: Other Chevrolet Metro I

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 on PCM ground terminals. See «POWERTRAIN CONTROL MODULE (PCM) CONNECTOR TERMINAL IDENTIFICATION»(ref-181-S09080159222000030800000). see scheme 1 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»(ref-181-S09080159222000030800000). see scheme 1 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.

ENGINE SENSORS & SWITCHES

Note. For additional sensor testing specifications, see appropriate SENSOR OPERATING RANGE CHARTS article.

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

Scheme 7

1. Camshaft Position (CMP) Sensor (1.0L) A malfunction in CMP sensor circuit can set Diagnostic Trouble Code (DTC) P0340. For test procedure with DTC set, see appropriate SELF-DIAGNOSTICS article. Use the following procedure to diagnose CMP sensor. Ensure air gap measures.008-.016" (.2-.4 mm). If air gap is not as specified, align signal rotor ridge with CMP sensor. Loosen CMP sensor and adjust clearance to specification. Tighten sensor screws to 44 INCH lbs. (5 N.m). If air gap is correct, disconnect distributor 2-pin electrical connector. Measure resistance between connector terminals No. 1 (Red wire) and No. 2 (White wire). CMP sensor resistance should be 185-275 ohms at 14-122°F (-10 to 50°C). If resistance is not as specified, replace CMP sensor.
2. Camshaft Position (CMP) Sensor (1.3L & 1.8L) A malfunction in CMP sensor circuit can set Diagnostic Trouble Code (DTC) P0340. For test procedure with DTC set, see appropriate SELF-DIAGNOSTICS article.
3. Crankshaft Position (CKP) Sensor A malfunction in CKP sensor circuit can set Diagnostic Trouble Code (DTC) P0335. For test procedure with DTC set, see appropriate SELF-DIAGNOSTICS article.
4. Electrical Load Diode Module (1.0L & 1.3L) Electric load diode is located under glove box, next to cigarette lighter, taped to instrument panel harness. See «IDLE-UP CIRCUIT (1.0L & 1.3L)»(ref-181-S17090572152000030800000) under IDLE CONTROL SYSTEM. To test electrical load diode module circuit, see «ELECTRICAL LOAD IDLE-UP CIRCUIT (1.0L & 1.3L)»(ref-181-S29903188232000030800000) under CIRCUIT TESTS.
5. Electrical Load Idle-Up Signal (1.8L) Electrical load idle-up signal is received directly from taillight relay and rear defogger relay. To test electrical idle-up signal circuit, see «ELECTRICAL LOAD IDLE-UP CIRCUIT (1.8L)»(ref-181-S01525684442000030800000) under CIRCUIT TESTS.
6. Engine Coolant Temperature (ECT) Sensor A malfunction in ECT sensor circuit can set a related Diagnostic Trouble Code (DTC). For test procedure with DTC set, see appropriate SELF-DIAGNOSTICS article. An out-of-calibration ECT sensor may not set a DTC. Use the following procedure to test sensor calibration. Locate and remove ECT sensor from thermostat housing. Using an ohmmeter, measure resistance of ECT sensor at specified temperatures. See «ENGINE COOLANT TEMPERATURE (ECT) SENSOR RESISTANCE»(ref-181-S37409592682000030800000) table. If resistance is not within specification, replace ECT sensor. ENGINE COOLANT TEMPERATURE (ECT) SENSOR RESISTANCE (1) Temperature °F (°C) Ohms 176 (80) 315 158 (70) 435 140 (60) 580 122 (50) 810 113 (45) 940 104 (40) 1150 95 (35) 1360 86 (30) 1600 77 (25) 2000 68 (20) 2400 59 (15) 3000 50 (10) 3600 41 (5) 4600 32 (0) 5700 23 (-5) 7400 14 (-10) 9800 5 (-15) 12,700 -4 (-20) 16,000 (1) Measure resistance across sensor terminals.
7. Fuel Level Sensor (1.0L & 1.3L) A malfunction in fuel level sensor circuit can set Diagnostic Trouble Codes (DTCs) P0461 and P0463. For test procedure with DTC set, see appropriate SELF-DIAGNOSTICS article.
8. Fuel Tank Pressure Sensor See «FUEL EVAPORATION»(ref-181-S28572725332000030800000) under EMISSION SYSTEMS & SUBSYSTEMS.
9. Intake Air Temperature (IAT) Sensor A malfunction in IAT sensor circuit can set a related Diagnostic Trouble Code (DTC). For test procedure with DTC set, see appropriate SELF-DIAGNOSTICS article. An out-of-calibration IAT sensor may not set a DTC. Use the following procedure to test sensor calibration. Locate and remove IAT sensor. See «INTAKE AIR TEMPERATURE (IAT) SENSOR LOCATION»(ref-181-S37654404142000030800000) table. Using an ohmmeter, measure resistance of IAT sensor at specified temperatures. See «INTAKE AIR TEMPERATURE (IAT) SENSOR RESISTANCE»(ref-181-S09323519422000030800000) table. If resistance is not within specification, replace IAT sensor. INTAKE AIR TEMPERATURE (IAT) SENSOR LOCATION Application Location 1.0L In Lower Air Cleaner Assembly 1.3L In Air Inlet Duct 1.8L In Air Cleaner Assembly INTAKE AIR TEMPERATURE (IAT) SENSOR RESISTANCE (1) Temperature °F (°C) Ohms 176 (80) 315 158 (70) 435 140 (60) 580 122 (50) 810 113 (45) 940 104 (40) 1150 95 (35) 1360 86 (30) 1600 77 (25) 2000 68 (20) 2400 59 (15) 3000 50 (10) 3600 41 (5) 4600 32 (0) 5700 23 (-5) 7400 14 (-10) 9800 5 (-15) 12,700 -4 (-20) 16,000 (1) Measure resistance across sensor terminals.
10. Knock Sensor (1.8L) A malfunction in Knock Sensor (KS) circuit can set Diagnostic Trouble Code (DTC) P0325. For test procedure with DTC set, see SELF-DIAGNOSTICS article. Use the following procedure to diagnose KS. Locate KS on right rear of engine block, near water pump. KS has a Black connector. Using an ohmmeter, measure resistance between KS terminal and ground. If resistance is not one megohm or greater, replace KS. Disconnect KS connector. Connect a voltmeter between KS terminal and ground. Adjust voltmeter to 200 millivolts on AC scale. Tap on engine block near KS and note reading. If no reading is present, replace KS.
11. Heated Oxygen Sensor-1 A malfunction in Heated Oxygen Sensor-1 (HO2S-1) circuit can set a related Diagnostic Trouble Code (DTC). For test procedure with DTC set, see appropriate SELF-DIAGNOSTICS article. Use the following procedure to diagnose HO2S-1. A voltage is produced in response to amount of oxygen in exhaust gases. A lean mixture (high oxygen content) will produce a low voltage of about 100 mV. A rich mixture (low oxygen content) will produce a high voltage of about 900 mV. Voltage reading (activity) should vary above idle.
12. Heated Oxygen Sensor-2 A malfunction in Heated Oxygen Sensor-2 (HO2S-2) circuit can set a related Diagnostic Trouble Code (DTC). For test procedure with DTC set, see appropriate SELF-DIAGNOSTICS article. Use the following procedure to diagnose HO2S-2. A voltage is produced in response to amount of oxygen in exhaust gases. A lean mixture (high oxygen content) will produce a low voltage of about 100 mV. A rich mixture (low oxygen content) will produce a high voltage of about 900 mV. Unlike HO2S-1, HO2S-2 voltage reading (activity) should seem lazy if TWC is operating properly.
13. Manifold Absolute Pressure (MAP) Sensor A malfunction in MAP sensor circuit can set a related Diagnostic Trouble Code (DTC). For test procedure with DTC set, see appropriate SELF-DIAGNOSTICS article. Use the following procedure to diagnose MAP sensor. If driveability problems exist, MAP sensor failure is suspected, and no DTCs are set, disconnect MAP sensor connector. If driveability improves, replace MAP sensor. Locate and remove MAP sensor. See «MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR LOCATION»(ref-181-S11265989672000030800000) table. Turn ignition on. Using a voltmeter, measure reference voltage from PCM to MAP sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. Voltage should be about 5 volts. Disconnect vacuum hose at MAP sensor. Install a hand-held vacuum pump. Turn ignition on. Check signal voltage at MAP sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. Apply vacuum and note change in signal voltage. As vacuum reading changes, signal voltage should change. Reading should be about 1.0-1.5 volts at high vacuum (idle position), or 4.0-4.5 volts at low vacuum (full throttle position). MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR LOCATION Application Location 1.0L & 1.3L On Firewall 1.8L On Throttle Body
14. Park/Neutral Position (PNP) Switch (1.8L With A/T) A malfunction in PNP switch circuit can set Diagnostic Trouble Code (DTC) P1780. For test procedure with DTC set, see appropriate SELF-DIAGNOSTICS article. Use the following procedure to diagnose PNP switch. Disconnect PNP switch connector (located on transmission next to shift linkage). Using an ohmmeter, check for continuity between PNP switch terminals No. 2 (Black/White wire) and No. 3 (Black wire) with gearshift in Park or Neutral. Continuity should exist. If continuity does not exist in specified gear ranges, replace PNP switch.
15. Throttle Position (TP) Sensor (1.0L) A malfunction in TP sensor circuit can set Diagnostic Trouble Code (DTC) P0121, P0122 or P0123. For test procedure with DTC set, see appropriate SELF-DIAGNOSTICS article. Use the following procedure to diagnose TP sensor. Insert a.14" (3.5 mm) feeler gauge between throttle stop screw and throttle lever. (Scheme 7) Check Idle Speed Control (ISC) motor plunger for contact with throttle lever screw. If ISC motor plunger is contacting throttle lever screw, engine must be brought to normal operating temperature. Install scan tool. Using scan tool, read TP sensor voltage parameter. Turn ignition on. Voltage reading should be.98-1.02 volts. If voltage is not.98-1.02 volts, adjust TP sensor. Loosen TP sensor mounting screws and turn TP sensor until voltage is as specified. Replace TP sensor if not adjustable.
16. Throttle Position (TP) Sensor (1.3L & 1.8L) A malfunction in TP sensor circuit can set Diagnostic Trouble Code (DTC) P0121, P0122 or P0123. For test procedure with DTC set, see appropriate SELF-DIAGNOSTICS article.
17. Vehicle Speed Sensor (1.0L & 1.3L) On A/T, Vehicle Speed Sensor (VSS) is mounted on transmission case. On M/T, VSS is integral with speedometer head. A malfunction in VSS circuit can set an A/T or M/T specific Diagnostic Trouble Code (DTC) P0500. For test procedure with DTC set, see appropriate SELF-DIAGNOSTICS article. Use illustration for identification of VSS terminals on M/T. (Scheme 8)
18. Vehicle Speed Sensor (1.8L) Vehicle Speed Sensor (VSS) is mounted on transaxle. A malfunction in VSS circuit can set Diagnostic Trouble Code (DTC) P0500. For test procedure with DTC set, see appropriate SELF-DIAGNOSTICS article.

MODULES, MOTORS, RELAYS & SOLENOIDS

Note. Manufacturer does not provide test procedures for many individual systems and components. For module, motor, relay and solenoid testing not listed, perform related DTC test procedure. See appropriate SELF-DIAGNOSTICS article.

A/C Compressor Control Module (1.0L & 1.3L)

See IDLE-UP CIRCUIT (1.0L & 1.3L) under IDLE CONTROL SYSTEM.

Diode Module (1.0L & 1.3L)

See ELECTRICAL LOAD DIODE MODULE (1.0L & 1.3L) under ENGINE SENSORS & SWITCHES.

Circuit Opening Relay (1.8L)

Circuit opening relay is located behind left side of instrument panel, above kick panel. To test circuit opening relay, see FUEL SYSTEM ELECTRICAL CIRCUIT test under appropriate NO START - ENGINE CRANKS OKAY test in appropriate BASIC DIAGNOSTIC PROCEDURES article.

Fuel Pump Relay (1.0L & 1.3L)

Fuel pump relay is located in underhood fuse/relay block. To test fuel pump relay, see FUEL SYSTEM ELECTRICAL CIRCUIT test under appropriate NO START - ENGINE CRANKS OKAY test in appropriate BASIC DIAGNOSTIC PROCEDURES article.

Main Relay

Main relay is located in underhood fuse/relay block. To test main relay, see MAIN RELAY CIRCUIT under appropriate NO START-ENGINE CRANKS OKAY in appropriate BASIC DIAGNOSTIC PROCEDURES article.

Early Fuel Evaporative Heater Relay (1.0L)

Note. Early Fuel Evaporation (EFE) heater may also be referred to as Positive Temperature Coefficient (PTC) heater.

1. Early Fuel Evaporative Heater (PTC HTR) relay is located in underhood fuse/relay block. Remove PTC HTR relay from fuse/relay block. Using an ohmmeter, ensure continuity exists between terminals No. 1 (White/Blue wire) and No. 2 (Yellow/Red wire) of PTC HTR relay.
2. Apply battery voltage to terminal No. 1 (White/Blue wire), and ground terminal No. 2 (Yellow/Red wire). Continuity should exist between terminals No. 3 (White/Black wire) and No. 4 (White wire) of PTC HTR relay. If continuity is not as specified, replace PTC HTR relay

Evaporative Emission (EVAP) Canister Purge Valve

See FUEL EVAPORATION under EMISSION SYSTEMS & SUBSYSTEMS.

Evaporative Emission (EVAP) Canister Purge Solenoid Valve (1.8L)

See FUEL EVAPORATION under EMISSION SYSTEMS & SUBSYSTEMS.

Evaporative Emission (EVAP) Canister Vent Solenoid (1.0L & 1.3L)

See FUEL EVAPORATION under EMISSION SYSTEMS & SUBSYSTEMS.

Evaporative Emission (EVAP) Fuel Tank Pressure Control Solenoid Vacuum Valve (1.0L & 1.3L)

See FUEL EVAPORATION under EMISSION SYSTEMS & SUBSYSTEMS.

Evaporative Emission (EVAP) Fuel Tank Pressure Vent Solenoid Valve (1.8L)

See FUEL EVAPORATION under EMISSION SYSTEMS & SUBSYSTEMS.

Exhaust Gas Recirculation (EGR) Solenoid Vacuum Valve (EGR-SVV 1.0L)

See EXHAUST GAS RECIRCULATION under EMISSION SYSTEMS & SUBSYSTEMS.

Idle Air Control (IAC) Valve (1.8L)

See IDLE AIR CONTROL (IAC) VALVE (1.8L) under IDLE CONTROL SYSTEM.

FUEL SYSTEM

Note. For fuel system pressure testing, see appropriate BASIC DIAGNOSTIC PROCEDURES article.

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

Fuel Pressure Regulator

On 1.0L, fuel pressure regulator is located on top of throttle body assembly. Fuel pressure regulator maintains fuel pressure applied to fuel injector 26 psi (1.8 kg/cm 2 ) more than intake manifold pressure. To test fuel pressure regulator, see FUEL SYSTEM PRESSURE TEST under BASIC FUEL SYSTEM CHECKS in appropriate BASIC DIAGNOSTIC PROCEDURES article.

On 1.3L, fuel pressure regulator is located on fuel rail. Fuel pressure regulator maintains fuel pressure applied to fuel injector 41 psi (2.9 kg/cm 2 ) more than intake manifold pressure. To test fuel pressure regulator, see FUEL SYSTEM PRESSURE TEST under BASIC FUEL SYSTEM CHECKS in appropriate BASIC DIAGNOSTIC PROCEDURES article.

On 1.8L, fuel pressure regulator is located on fuel sending unit assembly, on bottom of fuel filter. Fuel pressure regulator maintains fuel pressure at 44-50 psi (3.0-3.4 kg/cm 2 ). To test fuel pressure regulator, see FUEL SYSTEM PRESSURE TEST under BASIC FUEL SYSTEM CHECKS in appropriate BASIC DIAGNOSTIC PROCEDURES article.

Fuel Injector

PCM energizes fuel injectors sequentially when reference pulses are received from ignition system. Fuel pump pressurizes fuel injectors as long as engine is cranking and PCM is receiving ignition system reference pulses. To test fuel injector circuit, see FUEL INJECTOR CIRCUIT under CIRCUIT TESTS.

See RELAYS under MODULES, MOTORS, RELAYS & SOLENOIDS.

Idle-Up Circuit (1.0L & 1.3L)

PCM monitors a signal from electrical load diode module. An electrical load will be indicated by either heater blower motor request, rear defogger request or headlight/parking light request idle-up signal. PCM will adjust engine idle speed using Idle Speed Control (ISC) motor when an electrical load voltage signal is received. When electrical load voltage signal is removed, PCM will return engine to normal idle speed. To check electrical load idle-up circuit, see ELECTRICAL LOAD IDLE-UP CIRCUIT (1.0L & 1.3L) under CIRCUIT TESTS.

A/C compressor control module sends an idle-up signal to PCM when A/C compressor clutch is in operation. PCM will activate Idle Speed Control (ISC) motor. ISC motor opens throttle plate to control engine speed to prevent rough idle or stalling condition. To check A/C idle-up circuit, see A/C IDLE-UP CIRCUIT (1.0L & 1.3L) under CIRCUIT TESTS.

A/C Idle-Up Circuit (1.8L)

A/C compressor control module sends an idle-up signal to PCM when A/C compressor clutch is in operation. PCM compensates for extra engine load by adjusting engine idle speed through IAC valve. See IDLE AIR CONTROL (IAC) VALVE (1.8L) . PCM then sends A/C compressor control module an A/C cut-out signal to cut operation of A/C compressor clutch. A/C compressor control module will then resume normal cycling of A/C compressor clutch when engine returns to a lighter load. A malfunction in A/C idle-up circuit can set Diagnostic Trouble Code (DTC) P0505. For test procedure with DTC set, see appropriate SELF-DIAGNOSTICS article.

Idle Air Control (IAC) valve is located on bottom of throttle body. IAC valve opens and closes air by-pass passage according to signal from PCM. When open, air is supplied to intake manifold, which increases engine RPM for different engine loads. A malfunction in IAC valve circuit can set Diagnostic Trouble Code (DTC) P0505. For test procedure with DTC set, see appropriate SELF-DIAGNOSTICS article.

Idle Speed Control (ISC) Motor (1.0L & 1.3L)

Idle Speed Control (ISC) motor is located in lower section of throttle body. A malfunction in ISC motor circuit can set Diagnostic Trouble Code (DTC) P0505. For test procedure with DTC set, see appropriate SELF-DIAGNOSTICS article. ISC motor is adjusted at the factory. If manual adjustment is attempted, damage to ISC system may occur.

IGNITION SYSTEM

Note. For basic ignition checks, see appropriate BASIC DIAGNOSTIC PROCEDURES article.

Electronic Ignition Timing Control (1.0L)

Ignition timing is calculated by PCM based on current engine status. PCM receives signals indicating vehicle speed, manifold vacuum, throttle position and engine coolant temperature. PCM selects an appropriate, preprogrammed ignition timing adjustment. A signal is sent from PCM to ignition control module and changes ignition timing accordingly.

For ignition timing adjustment procedure, see IGNITION TIMING in appropriate ON-VEHICLE ADJUSTMENTS article. Diagnostic Trouble Code (DTC) P1530 can set in PCM memory during ignition timing adjustment. For test procedure with DTC set, see appropriate SELF-DIAGNOSTICS article.

Electronic Ignition Timing Control (1.3L)

Ignition timing is calculated by PCM based on current engine status. PCM receives signals indicating vehicle speed, manifold vacuum, throttle position and engine coolant temperature. PCM uses reference pulses from crankshaft position sensor to determine engine speed. PCM cannot operate ignition system without engine speed signal from crankshaft position sensor. PCM controls ignition timing by controlling ignition coils.

Ignition timing is controlled by PCM and is not adjustable. See IGNITION TIMING in appropriate ON-VEHICLE ADJUSTMENTS article. Diagnostic Trouble Code (DTC) P1530 can set in PCM memory during idle speed adjustment. For test procedure with DTC set, see appropriate SELF-DIAGNOSTICS article.

Electronic Ignition Timing Control (1.8L)

Ignition timing is controlled by PCM and is not adjustable. If ignition timing is not within specification, check for an engine mechanical failure. To check ignition timing, see ELECTRONIC IGNITION TIMING INSPECTION (1.8L) . If ignition signal is not present at PCM, Diagnostic Trouble Codes (DTCs) P1300 and P1310 can set in PCM memory. For test procedure with DTC set, see appropriate SELF-DIAGNOSTICS article.

Electronic Ignition Timing Retard (1.8L)

Knock sensor is located at right rear of engine in cylinder block near water pump. Knock sensor sends a variable AC voltage signal to PCM depending on engine detonation. PCM uses this signal to determine if ignition timing should be retarded. If a fault occurs in knock sensor circuit or knock sensor fails, DTC P0325 can set in PCM memory. For test procedure with DTC set, see appropriate SELF-DIAGNOSTICS article.

Scheme 8

EMISSION SYSTEMS & SUBSYSTEMS

Note. For emission system and subsystem testing not listed, perform related DTC test procedure. See appropriate SELF-DIAGNOSTICS article.

EGR System Check (1.0L)

1. With engine cool, ensure EGR valve is not loose or broken. Replace as necessary. Start engine and warm to normal operating temperature.
2. Place finger on bottom of EGR valve diaphragm. Increase engine speed. EGR valve diaphragm should move. If diaphragm does not move, allow engine to idle. Disconnect vacuum hose from EGR valve. (Scheme 10)
3. Apply 8 in. Hg of vacuum to EGR valve and place finger on diaphragm. Vacuum should hold, diaphragm should move and engine should run rough and may stall. If EGR valve operation is as specified, go to next step. If EGR valve operation is not as specified, replace EGR valve.
4. Check for carbon in valve which may cause a restriction. Restriction may be small enough so that engine may not stall, but large enough to cause DTC P0400 to set. See appropriate SELF-DIAGNOSTICS article. If EGR valve is plugged, replace EGR valve. If EGR valve is okay, go to «EGR PRESSURE TRANSDUCER (1.0L)»(ref-181-S25504229252000030800000).

Scheme 9

EGR Pressure Transducer (1.0L)

1. Check filter for any contamination and damage. Using compressed air, clean filter. Replace filter as necessary. (Scheme 11)
2. Remove 3 vacuum hoses from EGR pressure transducer. Place finger over one of 2 ports on top of EGR pressure transducer and blow into opposite port. If air passes through filter part of pressure transducer, go to next step. If air does not pass through filter part, replace EGR pressure transducer.
3. Connect a hand-held vacuum pump to one of 2 ports on top of EGR pressure transducer and plug opposite port. Blow into bottom port and apply vacuum. While blowing into bottom port, vacuum should be shown on vacuum pump gauge. Stop blowing into bottom port. Vacuum should read zero. If vacuum cannot be obtained or does not release, replace EGR pressure transducer.

Scheme 10

EGR Solenoid Vacuum Valve (EGR-SVV 1.0L)

Note. EGR solenoid vacuum valve and EGR by-pass valve are very similar in appearance. EGR by-pass valve does not have a filter on lower port.

1. Locate EGR Solenoid Vacuum Valve (EGR-SVV) on rear of engine, near EGR valve. Disconnect EGR-SVV vacuum hoses and electrical connector.
2. Check for continuity between each EGR-SVV terminal and body. If continuity exists at either terminal, replace EGR-SVV.
3. Measure resistance between terminals of EGR-SVV (valve side). Resistance should be 28-36 ohms at 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace EGR-SVV.
4. Blow air into EGR-SVV port No. 2. Air should flow out through air filter and NOT out through port No. 1. see scheme 7 Apply battery voltage and ground to EGR-SVV terminals. With EGR-SVV energized, blow air into port No. 2. Air should flow out through port No. 1 and NOT out through air filter. If operation is not as specified, replace EGR-SVV.

EGR By-Pass Valve (1.0L)

Note. EGR solenoid vacuum valve and EGR by-pass valve are very similar in appearance. EGR by-pass valve does not have a filter on lower port.

1. Locate EGR by-pass valve on rear of engine, near EGR valve. Disconnect EGR by-pass valve vacuum hoses and electrical connector.
2. Check for continuity between each EGR by-pass valve terminal and body. If continuity exists at either terminal, replace EGR by-pass valve.
3. Measure resistance between terminals of EGR by-pass valve (valve side). Resistance should be 33-44 ohms at 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace EGR by-pass valve.
4. Blow air into EGR by-pass valve port No. 2. Air should flow out through lower port and NOT out through port No. 1. see scheme 7 Apply battery voltage and ground to EGR by-pass valve terminals. With EGR by-pass valve energized, blow air into port No. 2. Air should flow out through port No. 1 and NOT out through lower port. If operation is not as specified, replace EGR by-pass valve.

Scheme 11

EGR Vacuum Supply (1.0L)

Locate EGR vacuum supply port on throttle body or intake manifold. Disconnect vacuum supply hose. Connect vacuum gauge to port. Start engine. Increase engine speed to 2000 RPM and note vacuum reading. At least 10 in. Hg of vacuum should be obtained. If vacuum is low, check vacuum supply port for restriction (carbon, dirt, etc.).

FUEL EVAPORATION

Evaporation Emission (EVAP) Canister Purge Check (1.0L & 1.3L)

Note. On 1.0L and 1.3L equipped with EVAP fuel tank pressure control solenoid vacuum valve, operation of EVAP canister purge system is conditional. EVAP canister purge system only operates when engine is sufficiently warmed up and Heated Oxygen Sensor (HO2S) is fully activated. Also, when purge hose is disconnected when checking for vacuum, fresh air will be drawn into purge line. PCM will detect a change in purge gas concentration and may stop purge operation. If this occurs, it is considered normal. If no vacuum is felt during following test, it may be necessary to repeat test to avoid replacement of good components.

1. Allow engine to cool to room temperature. Start engine when cold. Disconnect purge hose from EVAP canister. see scheme 8or see scheme 9. Check for vacuum at end of disconnected purge hose. Vacuum should not be present when engine temperature is less than normal operating temperature. Reconnect purge hose to EVAP canister and warm engine to normal operating temperature.
2. Disconnect purge hose from EVAP canister. Check for vacuum at end of disconnected purge hose. Vacuum should be present when engine temperature is more than normal operating temperature.

Required Service

PCV system may require service for an obstructed PCV valve or hose if any of the following conditions exist

1. Excessive exhaust emissions.
2. High crankcase pressure.
3. Oil leaks.
4. Oil in air cleaner.
5. Oil consumption.
6. Rough idle.
7. Sludge in engine.
8. Stalling or low idle speed.

A leaking PCV valve or hose could cause

1. Excessive exhaust emissions.
2. Incorrect crankcase pressure.
3. High idle speed.
4. Rough idle.
5. Stalling.

If engine idles roughly, check for clogged PCV valve, or plugged or broken hoses before attempting to repair incorrect idle. Check PCV valve application to ensure correct valve is fitted. Replace PCV valve as necessary.

Checking PCV Valve Function

1. Disconnect PCV valve vacuum hose from cylinder head cover. Run engine at idle. Place thumb over open end of PCV valve vacuum hose to check for vacuum. If vacuum does not exist, check for obstruction in source vacuum supply. If source vacuum supply is okay, replace PCV valve.
2. Turn ignition off. Remove PCV valve. Shake valve and listen for rattle of check valve inside. If a clear rattle is not heard, replace PCV valve.
3. Visually inspect valve for varnish or deposits which may make PCV valve operation sticky or restricted, or cause incomplete seating of valve. Replace PCV valve as necessary.
4. An engine must be sealed for PCV system to function as designed. If leakage, sludging or dilution of oil is noted and PCV system is functioning properly, check engine for cause and repair as required to ensure PCV system will continue to function properly.
5. An engine operating without any crankcase ventilation can be damaged. It is important to check PCV valve and air cleaner breather (if equipped) at regular intervals (at least every 30,000 miles). Check all hoses and clamps for failure or deterioration.

MISCELLANEOUS CONTROLS

Note. Although some controlled devices listed here are not technically engine performance components, they can affect driveability if they malfunction.

Manual Transmission Shift Indicator Light (1.0L With M/T)

UPSHIFT indicator light is controlled by PCM and illuminates when preferred transaxle shift point for maximum fuel economy is reached. To test manual transmission shift light circuit, see MANUAL TRANSMISSION SHIFT LIGHT CIRCUIT (1.0L WITH M/T) under CIRCUIT TESTS.

CIRCUIT TESTS

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