Engine Controls - System/component Tests - 1.5L: Other Mazda Protege BH

Power & Ground Circuits

Locate control module. Using a DVOM, backprobe appropriate power and ground circuits. See PIN VOLTAGE CHART S - 1.5L article, for terminal specification. If power and ground circuits are open or have excessive resistance, refer to WIRING DIAGRAMS - 1.5L article.

ECM LOCATION

AIRFLOW SENSOR (HEAT RESISTOR TYPE)

1. Pull rubber boot back from airflow sensor connector. Backprobe specified terminals for voltage. (Scheme 96) See «AIRFLOW SENSOR VOLTAGES (HEAT RESISTOR TYPE)»(ref-18619-S07308193242000123000000) table.
2. If voltages are not correct, check wiring for open or short. If voltages are still incorrect, replace airflow sensor.

AIRFLOW SENSOR VOLTAGES

Scheme 96

BRAKELIGHT SWITCH

Disconnect brakelight switch connector. Measure resistance between terminals of brakelight switch. With brake pedal released, continuity should not exist. With brake pedal depressed, continuity should be present. Replace switch as necessary.

CAMSHAFT POSITION (CMP) SENSOR

1. Remove distributor. Disconnect distributor 3-pin connector and leave 6-pin connector plugged-in. Connect analog voltmeter (or oscilloscope) negative lead to distributor ground (distributor body or Black/Pink wire terminal). With voltmeter positive lead, backprobe Violet/Red wire terminal. Turn ignition on and rotate distributor shaft by hand. Voltmeter should indicate one voltage pulse (5 volts) per revolution.
2. Move positive voltmeter lead to Violet/Green wire terminal. Rotate distributor shaft. Voltmeter should indicate 4 voltage pulses (5 volts) per revolution. Replace distributor if necessary.

CRANKSHAFT POSITION (CKP) SENSOR

Unplug CKP sensor connector. Measure resistance between Blue wire and Green wire on sensor. Resistance should be 500-600 ohms at 68 °F (20 °C). Replace sensor if not within specification. When installing sensor, adjust air gap to .020-.060" (.5-1.5 mm).

CLUTCH SWITCH

Disconnect clutch switch electrical connector. Using ohmmeter, check continuity between switch terminals. With clutch pedal depressed, continuity should be present. With clutch pedal released, continuity should not exist. Replace switch as necessary.

ENGINE COOLANT TEMPERATURE (ECT) SENSOR

Remove engine coolant temperature sensor. Place sensor and thermometer in container of coolant. Connect ohmmeter to sensor terminals. Slowly heat coolant. Note resistance at specified temperatures. See ECT SENSOR RESISTANCE table. Replace sensor as necessary.

ECT SENSOR RESISTANCE

HEATED OXYGEN SENSOR (HO2S)

1. Warm engine to normal operating temperature. Disconnect oxygen sensor connector. On front HO2S, connect negative voltmeter lead to ground. On rear oxygen sensor, connect voltmeter negative lead to terminal "B".
2. With engine running at idle, voltage at terminal "A" should be fluctuating at less than one volt. (Scheme 97) While accelerating engine, voltage should be.5-1.0 volt. While decelerating engine, voltage should be.1-.4 volt.
3. To test oxygen sensor heating element, let sensor cool to room temperature. Disconnect sensor connector. On front (3-pin) oxygen sensors, measure resistance across terminals "B" and "C". (Scheme 97) On rear (4-pin) oxygen sensors, measure resistance between terminals "C" and "D". Replace sensor if resistance is not about 6 ohms at 68°F (20° C).

Scheme 97

IDLE SWITCH

Idle switch is part of throttle position sensor. Perform adjustment procedure before replacing. See ADJUSTMENTS - 1.5L article. If sensor will not adjust properly, replace sensor.

INHIBITOR SWITCH

See TRANSMISSION RANGE SWITCH (A/T) .

INTAKE AIR TEMPERATURE (IAT) SENSOR

Sensor is located in air cleaner housing. With sensor disconnected, measure resistance between sensor terminals. See appropriate IAT SENSOR RESISTANCE table. Replace sensor as necessary.

IAT SENSOR RESISTANCE

NEUTRAL SWITCH (M/T)

Disconnect neutral switch. Using ohmmeter, check continuity between switch terminals. Ensure continuity exists with transmission in Neutral and does not exist in any other gear. Replace switch as necessary.

OXYGEN (O2S) SENSOR

See HEATED OXYGEN SENSOR (HO2S) .

POWER STEERING PRESSURE SWITCH (PSPS)

Disconnect power steering pressure switch electrical connector. Connect ohmmeter to PSPS terminal and ground. Start engine, and operate it at idle. Turn steering wheel from side to side, and observe ohmmeter. Ohmmeter should indicate continuity when front wheels are turned. Continuity should not exist when wheels are not turned. Replace switch as necessary.

THROTTLE POSITION SENSOR

See ADJUSTMENTS - 1.5L article for checking and adjustment procedures.

TRANSMISSION RANGE SWITCH (A/T)

Note. Transmission range switch may also be known as inhibitor switch.

Disconnect Transmission Range (TR) switch electrical connector. Connect ohmmeter to indicated switch terminals. See appropriate Fig. (Scheme 98). Continuity should be present with gearshift in Park and Neutral positions. Continuity should not exist in any other gear positions. Replace switch as necessary.

Scheme 98

VEHICLE SPEED SENSOR (VSS)

See PIN VOLTAGE CHART S - 1.5L article.

FUEL PUMP RELAY

Remove fuel pump relay (located to right of center console). Check continuity between terminals "C" and "D". (Scheme 99) Continuity should not exist. Apply 12 volts to terminal "A", and ground terminal "B". Continuity should exist between terminals "C" and "D" with 12 volts applied. Replace relay as necessary.

Scheme 99

MAIN RELAY

1. Ensure main relay clicks when ignition is turned on and off. If no sound is heard, remove relay (located in main fuse box). Apply 12 volts to terminal "A", and ground terminal "B".
2. Using ohmmeter, check continuity between terminals "C" and "D". Continuity should be present with 12 volts applied. Continuity should not exist without voltage applied. Replace main relay as necessary.

EGR Solenoid

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

Pressure Regulator Control Solenoid

Disconnect vacuum hose from pressure regulator control solenoid. Blow air through solenoid port "A". (Scheme 100) Ensure air flows through port "B". Disconnect solenoid valve electrical connector. Connect 12 volts and ground to solenoid terminals. Blow air through solenoid port "A". Air should flow through valve air filter. Replace solenoid as necessary.

Scheme 100

Purge Control Solenoid

See FUEL EVAPORATION under EMISSION SYSTEMS & SUB-SYSTEMS.

VICS Solenoid

See VARIABLE INERTIA CHARGING SYSTEM under AIR INDUCTION SYSTEMS.

VRIS Solenoid

See VARIABLE RESONANCE INDUCTION SYSTEM under AIR INDUCTION SYSTEMS.

FUEL DELIVERY

Note. For fuel system pressure testing, see BASIC TESTING - 1.5L article.

Fuel Pump Circuit

See FUEL PRESSURE under FUEL SYSTEM in BASIC TESTING - 1.5L article.

Fuel Pressure Regulator

See FUEL PRESSURE under FUEL SYSTEM in BASIC TESTING - 1.5L article.

Pressure Regulator Control

1. Engine must be at operating temperature (150°-200°F (66°-93°C)) and ambient temperature must be high. Turn engine off. Disconnect vacuum hose at fuel pressure regulator and connect a vacuum gauge to hose.
2. Without touching throttle, start engine. Observe vacuum gauge. Vacuum should not exist for a period of 1-3 minutes. If vacuum is present, check vacuum routing, pressure regulator control solenoid, and related circuits.
3. If vacuum gauge shows intake manifold vacuum after specified amount of time, system is okay. (Scheme 101) If intake manifold vacuum is not present after 3 minutes, check vacuum source, pressure regulator control solenoid and related circuits.

See PRESSURE REGULATOR CONTROL SOLENOID under SOLENOIDS .

Scheme 101

Fuel Injectors

Using stethoscope, listen for normal clicking sound at each injector during idle and acceleration. If clicking sound is not heard, check injector wiring circuit, or main relay and circuit.

Fuel Injector Resistance

Disconnect fuel injector electrical connector. Using ohmmeter, measure resistance between injector terminals. Resistance should be 12-16 ohms. Replace injector as necessary.

Injector Fuel Leakage

1. Relieve fuel system pressure. See procedures in BASIC TESTING - 1.5L article. Remove air valve or dynamic chamber as necessary. Remove delivery pipe with hoses still connected. Remove fuel injectors. If necessary, secure injectors tightly onto delivery pipe using wire. CAUTION: Ensure injectors are securely tied to delivery pipe. If injectors are not properly secured to delivery pipe, fuel may spray from loose connections.
2. Connect a jumper wire between terminals F/P and GND of diagnostic connector located near battery. (Scheme 102) Turn ignition on. Ensure no fuel leakage exists at injectors. After one minute, a single drop of fuel is acceptable. If fuel excessive leakage is present, replace faulty injector.

Scheme 102

Bypass Air Control (BAC) Valve

Remove BAC valve from throttle body. Let valve cool. Place air valve in water at temperature greater than 176°F (80°C) or heat with heat gun. Plunger should move outward. (Scheme 103)

Scheme 103

ISC Valve

Disconnect ISC valve electrical connector. Connect ohmmeter to ISC valve 2-wire connector. Measure resistance. See ISC RESISTANCE SPECIFICATIONS table. If resistance is not within specification, replace ISC valve.

ISC RESISTANCE SPECIFICATIONS

IGNITION SYSTEM

Note. For basic ignition checks, see BASIC TESTING - 1.5L article.

DECELERATION CONTROL SYSTEM

Note. Deceleration control system is a function of dashpot and ECM. Dashpot prevents sudden closure of throttle valve. ECM controls fuel cut during deceleration. For adjustment and testing, see ADJUSTMENTS - 1.5L article.

System Check

Check all connectors and hose routing. Check for cracks, leakage and restrictions, and repair as necessary. Start engine and operate throttle. Diaphragm of EGR control valve should not move while engine is cold. Warm engine to operating temperature. Increase engine speed to about 2000 RPM, EGR control valve diaphragm should move. If no movement is detected, check EGR valve, solenoids and position sensor. (Scheme 104)

Scheme 104

EGR Valve

Warm engine to normal operating temperature and operate at idle. Disconnect and plug vacuum hose at EGR control valve. Engine should run smoothly. Connect vacuum pump to EGR control valve, and apply 1.5-3.5 in. Hg vacuum. Engine should run rough or stall. If engine does not operate as specified, clean or replace EGR control valve.

EGR Position Sensor

1. Disconnect EGR position sensor electrical connector. Disconnect vacuum hose from EGR control valve. Apply vacuum to EGR control valve.
2. Check sensor resistance between indicated terminals. See «EGR POSITION SENSOR RESISTANCE»(ref-18619-S08720607832000123000000) table. (Scheme 105) If resistance is not within specifications, replace sensor.

EGR POSITION SENSOR RESISTANCE

Scheme 105

EGR Vacuum Solenoid Valve

Remove EGR vacuum solenoid. Try to blow air through valve. Air should not flow. Apply 12 volts and a ground to solenoid valve terminals. (Scheme 106) Blow air through valve. Air should flow with voltage applied. If valve does not operate as described, replace valve.

EGR Vent Solenoid Valve

Remove EGR vacuum solenoid. Air should flow through all 3 ports with power not applied to valve. With 12 volts applied to vent solenoid, air should flow through ports "A" and "B" only. (Scheme 106) Air should NOT pass through port "C" with power applied.

Scheme 106

Charcoal Canister

Check for loose, missing, cracked and broken connections and parts. Repair or replace as necessary. No liquid should exist in canister.

2-Way Check Valve

Remove check valve. Connect a vacuum pump to one end of check valve. Air should flow with about 1-1.7 in. Hg applied. Connect vacuum pump to other end of check valve. Air should also flow with about 1-1.7 in. Hg applied. Replace valve as necessary.

Tank Pressure Control Valve

1. Remove valve (located on top of fuel tank). Apply pressure to inlet port (on same side as electrical connector). At pressures less than .5 psi, air should not flow. At pressures greater than .9 psi, air should flow through valve.
2. Using a vacuum pump, apply vacuum to inlet port. At vacuum greater than .3 in Hg. air should flow through valve.

Scheme 107

Fuel Vapor Rollover Valve

Remove fuel vapor valve. Hold valve in level upright position. Blow air into port (hose barb). Air should flow through valve to lower port. Turn valve upside down. Air should not flow. Replace valve as necessary.

Purge Control Solenoid Valve

Unplug purge control solenoid electrical connector. Ensure air cannot flow through solenoid valve vacuum ports. Connect 12 volts and a ground to solenoid valve terminals. Blow air through check valve. Air should flow through valve. Replace if valve does not operate as described.

Separator

Check for loose, missing, cracked and broken connections and parts. Repair or replace as necessary. No liquid should exist in canister.