Engine Controls - System & Component Testing: Other Suzuki Vitara I

COMPUTERIZED ENGINE CONTROLS

Note. For ECM terminal identification, see PIN VOLTAGE/CIRCUIT RESISTANCE CHARTS article. For engine performance related component locations, see appropriate figure under COMPONENT LOCATIONS . For vacuum diagram identification, see VACUUM DIAGRAMS article.

ENGINE CONTROL MODULE

Perform testing at ECM. ECM is located under instrument panel, behind glove box. (Scheme 62)

Scheme 62

ECM Power & Ground Circuits

For ECM power and ground circuit testing, see A3: ENGINE CONTROL MODULE POWER & GROUND CIRCUIT CHECK/ENGINE DOES NOT START under SYSTEM TEST in appropriate SELF DIAGNOSTICS article.

ECM Circuit Resistance

Perform circuit resistance tests with ECM/PCM harness connectors disconnected. See CIRCUIT RESISTANCE CHARTS in PIN VOLTAGE/CIRCUIT RESISTANCE CHARTS article.

ENGINE SENSORS & SWITCHES

Note. For ECM terminal identification, see PIN VOLTAGE/CIRCUIT RESISTANCE CHARTS article. For engine performance related component locations, see appropriate figure under COMPONENT LOCATIONS . For vacuum diagram identification, see VACUUM DIAGRAMS article.

CAMSHAFT POSITION SENSOR

For Camshaft Position (CMP) sensor testing procedures, see DTC P0340 in appropriate SELF-DIAGNOSTICS article.

CRANKSHAFT POSITION SENSOR

For Crankshaft Position (CKP) sensor testing procedures, see DTC P0335 in appropriate SELF-DIAGNOSTICS article.

ENGINE COOLANT TEMPERATURE SENSOR

Remove Engine Coolant Temperature (ECT) sensor from intake manifold and place in water with a thermometer. Heat water to specified temperature and check resistance. (Scheme 63) Replace sensor if resistance is not within specification.

Scheme 63

HEATED OXYGEN SENSOR NO. 1

1. Start engine and allow it to reach normal operating temperature. Pull back seal at Heated Oxygen Sensor (HO2S) No. 1 connector. Using DVOM, backprobe HO2S No. 1 connector between sensor signal and sensor ground terminals. (Scheme 64)
2. Increase engine speed to 2000 RPM and hold for about one minute while observing voltmeter. Reading should fluctuate between zero and one volt, without being constantly high or low. If voltage is not as specified, see DTCs P0131 and P0132 in appropriate SELF-DIAGNOSTICS article.

Scheme 64

HEATED OXYGEN SENSOR NO. 2

1. Start engine and allow it to reach normal operating temperature. Pull back seal at Heated Oxygen Sensor (HO2S) No. 2 connector. Using a voltmeter, backprobe HO2S No. 2 connector between sensor signal and sensor ground terminals. (Scheme 64)
2. Increase engine speed to 2000 RPM and hold for about one minute while observing voltmeter. Voltage readings should have slight fluctuations above and below.3 volts. If voltage is not as specified, see DTC P0136 and DTC P0420 in appropriate SELF-DIAGNOSTICS article.

HEATED OXYGEN SENSOR HEATERS NO. 1 & 2

Turn ignition off. Disconnect Heated Oxygen (HO2S) sensor No. 1 or 2 pigtail connector. Using an ohmmeter, measure resistance between VB and GND terminals. (Scheme 64) See HEATED OXYGEN SENSOR HEATER RESISTANCE table. Replace HO2S if resistance is not as specified.

HEATED OXYGEN SENSOR HEATER RESISTANCE @ 68°F (20°C)

Aerio

Measure resistance between IAT sensor terminals while it is immersed in a container of water. Heat water slowly and ensure resistance changes as specified. See IAT SENSOR RESISTANCE SPECIFICATIONS table. (Scheme 65) If resistance is not as specified, replace IAT sensor.

Scheme 65

Grand Vitara, Vitara & XL-7

1. Disconnect IAT sensor connector. Turn ignition on. Check voltage between ground and Light Blue wire (Grand Vitara and XL-7) or Gray/Red wire (Vitara) terminal of connector. If voltage is not 4-6 volts (4.5-5.5 on Grand Vitara and XL-7), check wiring harness for an open or short. If voltage is as specified, go to next step.
2. Remove IAT sensor and place in container of water with a thermometer. Heat water to specified temperature and check resistance. See «IAT SENSOR RESISTANCE SPECIFICATIONS»(ref-158706-S33921398402003101500000) table. (Scheme 66) Replace IAT sensor if resistance is not within specification.

IAT SENSOR RESISTANCE SPECIFICATIONS

Scheme 66

KNOCK SENSOR

For testing procedures, see DTC P0327 and P0328 in appropriate SELF-DIAGNOSTICS article.

1. Disconnect MAP sensor from connector and remove. Measure voltage between "Vout" and "Ground" according to test procedures found in (Scheme 67). Refer to «MAP SENSOR OUTPUT SIGNAL (AERIO)»(ref-158706-S28237006812003101500000) for voltage specifications and test conditions.
2. If voltage is not within specification, replace MAP sensor. MAP SENSOR OUTPUT SIGNAL (AERIO) Altitude (Feet) Vacuum (In. Hg) Output Voltage 0-2000 29.9-27.8 3.3-4.3 2001-5000 27.8-24.9 3.0-4.1 5001-8000 24.9-22.3 2.7-3.7 8001-10,000 22.3-20.7 2.5-3.3

Scheme 67

MANIFOLD DIFFERENTIAL PRESSURE SENSOR (GRAND VITARA, VITARA & XL-7)

1. Remove Manifold Differential Pressure (MDP) sensor from intake manifold. Inspect intake manifold vacuum passage, MDP sensor air vent hole and vacuum passage for clogs. Clean passages if necessary. Inspect sensor O-ring for damage and deterioration. If no problem is found, go to next step.
2. Connect three 1.5 volt batteries in series. Connect positive terminal of batteries to MDP sensor terminal No. 3 (Vin). Connect negative terminal of batteries to MAP sensor terminal No. 2 (GROUND). (Scheme 67) Using DVOM, measure voltage between MDP sensor terminal No. 1 (Vout) and ground side of batteries. Voltage reading should be 4.5 volts. Using hand-held vacuum pump apply specified vacuum to MDP sensor, and check MDP sensor output voltage at specified pressure. See «MANIFOLD DIFFERENTIAL PRESSURE SENSOR OUTPUT VOLTAGE (GRAND VITARA, VITARA & XL-7)»(ref-158706-S04229861302003101500000) table for voltage specifications. If voltage readings are not within specifications, replace MDP sensor and retest system.

MANIFOLD DIFFERENTIAL PRESSURE SENSOR OUTPUT VOLTAGE (GRAND VITARA, VITARA & XL-7)

Note. To avoid damaging MAF sensor, DO NOT remove sensor from throttle body. When MAF sensor requires replacement, replace throttle body.

1. Turn ignition off. Disconnect Mass Airflow (MAF) sensor 3-pin harness connector. Turn ignition on. Measure voltage between ground and MAF sensor harness connector terminal No. 3 (Green wire). If battery voltage is present, go to next step. If battery voltage is not present, check wiring for an open circuit or poor connection. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
2. Turn ignition off. Reconnect MAF sensor harness connector. Access ECM. (Scheme 62) Turn ignition on. Backprobing at ECM, measure voltage between ground and ECM connector C46 terminal No. 24. (Scheme 77) Voltage should be.5-1.0 volt. Start engine and ensure voltage is lower than 5 volts and increases as RPM increases. If voltages are to specification, system is okay. If voltages are not to specification, go to DTC P0101: MASS AIR FLOW SENSOR - PERFORMANCE PROBLEM under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.

Grand Vitara

1. Disconnect MAF sensor connector. Turn ignition on. Using a DVOM, measure voltage between MAF sensor connector Blue/Black wire and ground. If battery voltage is indicated, go to next step. If battery voltage is not indicated, repair open or short circuit in Blue/Black wire between MAF sensor and main relay.
2. Turn ignition off and remove ECM/PCM cover. Reconnect MAF sensor. Turn ignition on and measure voltage (backprobe) between ECM/PCM connector C51-3 terminals No. 20 (Grey/Yellow wire) and No. 23 (Violet/White wire). Voltage reading should be .5-1.0 volt. Start engine. At idle, voltage should read between 1.5-1.8 volts. Voltage should stay below 5 volts but increase as engine speed is increased. If test results are not as specified, go to DTC P0101: MASS AIRFLOW (MAF) CIRCUIT PERFORMANCE PROBLEM under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.

Vitara

1. Disconnect MAF sensor connector. Turn ignition on. Using a DVOM, measure voltage between MAF sensor connector Blue/Black wire and ground. If battery voltage is indicated, go to next step. If battery voltage is not indicated, repair open or short circuit in Blue/Black wire between MAF sensor and main relay.
2. Turn ignition off and remove ECM/PCM cover. Reconnect MAF sensor. Turn ignition on and measure voltage (backprobe) at ECM/PCM connector terminal C51-3 terminal No.10 (Violet/White wire). Voltage reading should be 1.0-1.6 volts. Start engine. At idle, voltage should read between 1.7-2.0 volts. Voltage should stay below 5 volts but increase as engine speed is increased. If test results are not as specified, go to DTC P0101: MASS AIR FLOW (MAF) SENSOR CIRCUIT PERFORMANCE PROBLEM under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.

XL-7

1. Disconnect MAF sensor connector. Turn ignition on. Using a DVOM, measure voltage between MAF sensor connector Blue/Black wire and ground. If battery voltage is indicated, go to next step. If battery voltage is not indicated, repair open or short circuit in Blue/Black wire between MAF sensor and main relay.
2. Turn ignition off and remove ECM/PCM cover. Reconnect MAF sensor. Turn ignition on and measure voltage (backprobe) between ECM/PCM connector C51-3 terminals No. 5 (Grey/Yellow wire) and No. 10 (Purple/White wire). Voltage reading should be .5-1.0 volts. Start engine. At idle, voltage should read between 1.5-1.8 volts. Voltage should stay below 5 volts but increase as engine speed is increased. If test results are not as specified, go to DTC P0101: MASS AIRFLOW (MAF) CIRCUIT PERFORMANCE PROBLEM under DIAGNOSTIC TESTS in «SELF-DIAGNOSTICS - XL7»(ref-159350) article.

POWER STEERING PRESSURE SWITCH

1. Start engine. Using a voltmeter, measure voltage (backprobe) between ground and specified ECM/PCM harness connector terminal with steering wheel in specified position. See «PSP SWITCH VOLTAGE»(ref-158706-S20896627892003101500000) table. If reading is as specified, signal circuit is okay. If reading is not as specified, go to next step. PSP SWITCH VOLTAGE Application/Wheel Position PCM Connector/Terminal No. (1) Volts Aerio Straight C46/17 10-14 Turned To Stop C46/17 0-1 Grand Vitara & XL-7 Straight E61-26 10-14 Turned To Stop E61-26 0-1 Vitara Straight C51-3-7 10-14 Turned To Stop C51-3-7 0-1 (1) For identification of PCM harness connectors and wire terminals, see «PIN VOLTAGE/CIRCUIT RESISTANCE CHARTS»(ref-159417) article.
2. Turn ignition off. Disconnect wire connector from PSP switch on power steering pump. Turn ignition on. Measure voltage between ground and PSP switch signal wire at connector. If reading is 10-14 volts, replace PSP switch. If reading is not as specified, check for an open or short to ground in signal wire. Repair as necessary. If wire is okay, replace ECM/PCM. Retest system.

Scheme 68

Scheme 69

1. Disconnect negative battery cable and Throttle Position (TP) sensor harness connector. (Scheme 68)or (Scheme 69). Using an ohmmeter, check resistance between indicated terminals. See «THROTTLE POSITION SENSOR RESISTANCE»(ref-158706-S08031181632003101500000) table. If resistance is not as specified, replace TP sensor. THROTTLE POSITION SENSOR RESISTANCE Application Ohms (1) Aerio (2) Grand Vitara, Vitara & XL-7 Between Terminals No. 1 & 3 4000-6000 Between Terminals No. 1 & 2 (Vitara & XL-7) At Idle 20 At Wide Open Throttle 6000 Between Terminals No. 2 & 3 (Grand Vitara) At Idle 0 At Wide Open Throttle 4600 (1) Resistance should vary according to throttle opening. (2) Information not available from manufacurer.
2. On Grand Vitara, if resistance is not as specified, adjust TP sensor. See «THROTTLE POSITION SENSOR»(ref-157310-S16134775362003080800000) in ON-VEHICLE ADJUSTMENTS article. If resistance is not as specified after adjustment, replace TP sensor. For further diagnostic procedures, see appropriate SELF-DIAGNOSTICS article.

TRANSMISSION RANGE SENSOR

Disconnect negative battery cable. Disconnect harness connector at Transmission Range Sensor (TRS) on side of transmission. Using an ohmmeter, ensure continuity exists between indicated sensor terminals in specified gear range. (Scheme 70)or (Scheme 71). See TRANSMISSION RANGE SENSOR RESISTANCE (AERIO) or TRANSMISSION RANGE SENSOR RESISTANCE (GRAND VITARA, VITARA & XL-7) table. Ensure continuity does not exist between specified terminals and ground. Replace TRS if it does not test as specified.

Scheme 70

Scheme 71

TRANSMISSION RANGE SENSOR RESISTANCE (AERIO)

TRANSMISSION RANGE SENSOR RESISTANCE (GRAND VITARA, VITARA & XL-7)

For Vehicle Speed Sensor (VSS) testing procedure, see DTC P0500: VEHICLE SPEED SENSOR (VSS) MALFUNCTION in SELF-DIAGNOSTICS - AERIO 2.0L article.

For vehicle speed sensor inspection. Back probing, connect voltmeter between VSS signal wire at ECM/PCM and ground. On Vitara, backprobe ECM/PCM terminal C51-2 terminal No. 25 (Blue/Yellow wire). On Grand Vitara, backprobe ECM/PCM terminal C51-3 terminal No. 1 (Blue/Yellow wire). On XL-7, backprobe ECM/PCM terminal C51-1 terminal No. 14 (Blue/Yellow wire). Hoist vehicle, put vehicle in neutral. Turn ignition switch to ON position. Turn right rear tire slowly, left rear tire needs to be held stationary. While rotating tire, voltmeter should fluctuate a few times between 0-1 volt and 8-14 volts (exact number of times not given by manufacturer). If voltages are not as specified, see DTC P0500. VEHICLE SPEED SENSOR (VSS) MALFUNCTION under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.

Remove VSS from transaxle. Inspect VSS assembly for damage or binding. Using an ohmmeter, measure resistance between sensor terminals. See VEHICLE SPEED SENSOR RESISTANCE table.

VEHICLE SPEED SENSOR RESISTANCE

RELAYS & SOLENOIDS

Note. For ECM terminal identification, see PIN VOLTAGE/CIRCUIT RESISTANCE CHARTS article. For engine performance related component locations, see appropriate figure under COMPONENT LOCATIONS . For vacuum diagram identification, see VACUUM DIAGRAMS article.

Fuel Pump Relay & Main Relay (Aerio)

Note. A/C condenser fan, fuel pump, heated oxygen sensor and main relays are identical. Following test procedures apply to both.

1. Turn ignition off. Disconnect negative battery cable. Disconnect relay connector and remove relay. (Scheme 72) Using DVOM, measure resistance between relay terminals No. 1 and 2. (Scheme 73) Resistance should be infinity. Measure resistance between relay terminals No. 3 and 4. Resistance should be 70-110 ohms. If resistance is not as specified, replace relay.
2. Energize relay by applying battery voltage and ground to terminals No. 3 and 4. Check continuity between terminals No. 1 and 2. If continuity is present, relay is okay. If continuity is not present, replace relay.

Scheme 72

Scheme 73

Fuel Pump Relay & Main Relay (Grand Vitara, Vitara & XL-7)

Note. Fuel pump and main relay are identical. Following test procedures apply to both.

1. Turn ignition off. Disconnect negative battery cable. Disconnect relay connector and remove relay. (Scheme 74)or (Scheme 75) for location. Using an ohmmeter, check continuity between terminals No. "A" and "B". (Scheme 76) 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 70-110 ohms (79-95 on Vitara), go to next step. If resistance is not as specified, 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.

Scheme 74

Scheme 75

Scheme 76

EVAP Canister Purge Valve

See FUEL EVAPORATION under EMISSION SYSTEMS & SUB-SYSTEMS.

Idle Air Control (IAC) Valve

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

Fuel Tank Pressure Control Solenoid Valve

See FUEL EVAPORATION under EMISSION SYSTEMS & SUB-SYSTEMS.

FUEL SYSTEM

Note. For ECM terminal identification, see PIN VOLTAGE/CIRCUIT RESISTANCE CHARTS article. For engine performance related component locations, see appropriate figure under COMPONENT LOCATIONS . For vacuum diagram identification, see VACUUM DIAGRAMS article.

Fuel Pump Relay

See RELAYS under RELAYS & SOLENOIDS.

Fuel Pressure Regulator

For fuel pressure regulator testing, following appropriate testing procedure under FUEL PRESSURE .

1. Using a mechanic's stethoscope, check each fuel injector for operating "clicking" sound as engine is cranked. If all fuel injectors made operating sound, fuel injector circuit is in good condition. If any one or all fuel injectors do not make operating sound, go to next step .
2. Disconnect connectors from fuel injectors with ignition switch OFF. Connect ohmmeter between terminals of injector and measure resistance. Resistance should be 10.8-13.2 ohms at 68°F (20°C). If resistance is not as specified, injector is faulty. If all injectors are within specification, go to next step.
3. Check for short to each other in fuel injector circuits. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If problem is found, repair as necessary. After repair, retest system. If no problem is found, go to next step.
4. Measure voltage between each Black/Red wire terminal and engine ground with ignition switch turned ON. If voltage is between 10-14 volts, go to next step. If voltage is not within specification, Black/Red wire circuit open or shorted to ground. If it is in good condition, check ECM power and ground circuit. See «ECM POWER & GROUND CIRCUITS»(ref-158706-S42531897472003101500000)
5. Turn ignition switch OFF. Disconnect connectors from ECM. ECM is located under instrument panel, behind glove box. Measure resistance between each Blue/Yellow, Blue/White, Blue/Red and Blue/Green wire terminal and vehicle body ground. If resistance is infinite, go to next step. If resistance is out of specification, Blue/Yellow, Blue/White, Blue/Red, Blue/Green wire shorted to ground.
6. With ignition switch OFF, measure voltage between Blue/Yellow, Blue/White, Blue/Red, Blue/Green wire terminal and vehicle body ground . Voltage should be zero volts. If voltage is within specification, go to next step. If voltage is not within specification, Blue/Yellow, Blue/White, Blue/Red, Blue/Green wire shorted to power supply circuit.
7. With ignition switch ON, measure voltage between Blue/Yellow, Blue/White, Blue/Red, Blue/Green wire terminal and vehicle body ground . Voltage should be 10-14 volts. If voltage is not within specification, Blue/Yellow, Blue/White, Blue/Red, Blue/Green wire circuit open. If voltage is within specification and injector is in good condition, substitute a known-good ECM and recheck.

Scheme 77

1. Using a mechanic's stethoscope, check each fuel injector for operating "clicking" sound as engine is cranked. If all fuel injectors made operating sound, go to next step. If any one or all fuel injectors do not make operating sound, go to step 3.
2. Turn ignition off. Disconnect ECM harness connectors C51-2. ECM is located under instrument panel, behind glove box. (Scheme 62) Using DVOM, measure resistance between specified circuits. See «CHECKING FUEL INJECTOR CIRCUITS AT ECM (GRAND VITARA)»(ref-158706-S37328250262003101500000) table. (Scheme 78) Resistance should be 10-14 ohms at 68°F (20°C). If resistance is not as specified, go to next step. If resistance is as specified, substitute ECM with known good unit and retest system. CHECKING FUEL INJECTOR CIRCUITS AT ECM (GRAND VITARA) Measure Between ECM Harness Connector Terminals Wire Color C51-2/6 & C51-2/20 Pink/Black C51-2/7 & C51-2/20 Pink C51-2/18 & C51-2/20 Pink/Blue C51-2/19 & C51-2/20 Pink/Green C51-2/27 & C51-2/20 Grey/Black C51-2/28 & C51-2/20 Grey/Green
3. Check for short to each other in fuel injector circuits. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If problem is found, repair as necessary. After repair, retest system. If no problem is found, go to next step.
4. If none of the injectors makes operating sounds, go to step 6. Check suspect fuel injector harness connectors for poor, loose corroded or damaged terminal connections. If problem is found, repair as necessary. If no problem is found, go to next step.
5. Measure resistance between fuel injector terminals. Resistance should be 10-14 ohms at 68°F (20°C). If resistance is as specified at all injectors, substitute ECM with known good unit and retest system. If resistance is not as specified at any injector, replace suspect injector. See «FUEL SYSTEM»(ref-157824-S42753626782003082700000) in REMOVAL, OVERHAUL & INSTALLATION article.
6. Turn ignition on. Using test light connected to ground, probe fuel injector harness connector terminal No. 2 (Blue/Black wire), at each injector. If test light illuminates, go to next step. If test light does not illuminate, check for open or short in Blue/Black wire between fuel injector and main relay. (Scheme 80) If problem is found, repair as necessary. After repair, retest system.
7. Using test light connected to battery voltage, probe fuel injector harness connector terminal No. 1. If test light does not illuminate, check for and repair open or short in appropriate circuit between injector and ECM. After repair, retest system. If test light illuminates, repeat step 5.

1. Using a mechanic's stethoscope, check each fuel injector for operating "clicking" sound as engine is cranked. If all fuel injectors made operating sound, go to next step. If any one or all fuel injectors do not make operating sound, go to step 3.
2. Turn ignition off. Disconnect ECM harness connectors C51-2 and C51-3. ECM is located under instrument panel, behind glove box. (Scheme 62) Using DVOM, measure resistance between specified circuits. See «CHECKING FUEL INJECTOR CIRCUITS AT ECM (VITARA)»(ref-158706-S17262790322003101500000) table. (Scheme 78) Resistance should be 13-16 ohms at 68°F (20°C). If resistance is not as specified, go to next step. If resistance is as specified, substitute ECM with known good unit and retest system. CHECKING FUEL INJECTOR CIRCUITS AT ECM (VITARA) Measure Between ECM Harness Connector Terminals Wire Color C51-2/1 & C51-3/4 Pink/Black C51-2/2 & C51-3/4 Pink C51-2/8 & C51-3/4 Pink/Blue C51-2/9 & C51-3/4 Pink/Green
3. Check for short to each other in fuel injector circuits. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If problem is found, repair as necessary. After repair, retest system. If no problem is found, go to next step.
4. If none of the injectors makes operating sounds, go to step 6. Check suspect fuel injector harness connectors for poor, loose corroded or damaged terminal connections. If problem is found, repair as necessary. If no problem is found, go to next step.
5. Measure resistance between fuel injector terminals. Resistance should be 13-16 ohms at 68°F (20°C). If resistance is as specified at all injectors, substitute ECM with known good unit and retest system. If resistance is not as specified at any injector, replace suspect injector. See «FUEL SYSTEM»(ref-157824-S42753626782003082700000) in REMOVAL, OVERHAUL & INSTALLATION article.
6. Turn ignition on. Using test light connected to ground, probe fuel injector harness connector terminal No. 2 (Blue/Black wire), at each injector. If test light illuminates, go to next step. If test light does not illuminate, check for open or short in Blue/Black wire between fuel injector and main relay. (Scheme 79) If problem is found, repair as necessary. After repair, retest system.
7. Using test light connected to battery voltage, probe fuel injector harness connector terminal No. 1. If test light does not illuminate, check for and repair open or short in appropriate circuit between injector and ECM. After repair, retest system. If test light illuminates, repeat step 5.

Scheme 78

Scheme 79

1. Using a mechanic's stethoscope, check each fuel injector for operating "clicking" sound as engine is cranked. If all fuel injectors made operating sound, go to next step. If any one or all fuel injectors do not make operating sound, go to step 3.
2. Turn ignition off. Disconnect ECM harness connectors C51-2 and C51-3. ECM is located under instrument panel, behind glove box. (Scheme 62) Using DVOM, measure resistance between specified circuits. See «CHECKING FUEL INJECTOR CIRCUITS AT ECM (XL-7)»(ref-158706-S20729184482003101500000) table. (Scheme 78) Resistance should be 14.2-14.8 ohms at 68°F (20°C). If resistance is not as specified, go to next step. If resistance is as specified, substitute ECM with known good unit and retest system. CHECKING FUEL INJECTOR CIRCUITS AT ECM (XL-7) Measure Between ECM Harness Connector Terminals Wire Color C51-2/1 & C51-3/4 Pink/Blue C51-2/2 & C51-3/4 Pink C51-2/8 & C51-3/4 Pink/Blue C51-2/9 & C51-3/4 Pink/Green C51-2/21 & C51-3/4 Grey/Black C51-2/22 & C51-3/4 Grey/Green
3. Check for short to each other in fuel injector circuits. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If problem is found, repair as necessary. After repair, retest system. If no problem is found, go to next step.
4. If none of the injectors makes operating sounds, go to step 6. Check suspect fuel injector harness connectors for poor, loose corroded or damaged terminal connections. If problem is found, repair as necessary. If no problem is found, go to next step.
5. Measure resistance between fuel injector terminals. Resistance should be 14.2-14.8 ohms at 68°F (20°C). If resistance is as specified at all injectors, substitute ECM with known good unit and retest system. If resistance is not as specified at any injector, replace suspect injector. See «FUEL SYSTEM»(ref-157824-S42753626782003082700000) in REMOVAL, OVERHAUL & INSTALLATION article.
6. Turn ignition on. Using test light connected to ground, probe fuel injector harness connector terminal No. 2 (Blue/Black wire), at each injector. If test light illuminates, go to next step. If test light does not illuminate, check for open or short in Blue/Black wire between fuel injector and main relay. (Scheme 80) If problem is found, repair as necessary. After repair, retest system.
7. Using test light connected to battery voltage, probe fuel injector harness connector terminal No. 1. If test light does not illuminate, check for and repair open or short in appropriate circuit between injector and ECM. After repair, retest system. If test light illuminates, repeat step 5.

Scheme 80

1. Release fuel pressure. See «RELIEVING FUEL PRESSURE»(ref-158706-S33624230102003101500000) . Using appropriate "T" connector and adapters, install fuel pressure gauge to fuel inlet at intake manifold. Check fuel pressure as ignition switch is cycled on and off. If fuel pressure is 38.4-44.0 psi (2.7-3.1 kg/cm 2 ), go to next step. If fuel pressure is not as specified, go to step 5 .
2. If fuel pressure maintains 28.4 psi (2.0 kg/cm 2 ) or greater for one minute after fuel pump stops, go to next step. If fuel pressure is not as specified, go to step 4 .
3. Start engine and allow it to reach normal operating temperature. If fuel pressure is 31.3-36.9 psi (2.2-2.6 kg/cm 2 ) with engine at idle, fuel pressure is okay. If fuel pressure is not as specified, check for clogged vacuum passage to fuel pressure regulator or faulty fuel pressure regulator. If problem is found, repair as necessary.
4. Check for fuel leaks from fuel feed hose, pipe or connections. If problem is found, repair as necessary. If no leaks are present, go to step 10 .
5. If fuel pressure is 38.4-44.0 psi (2.7-3.1 kg/cm 2 ) or more, go to next step. If fuel pressure is not as specified, go to step 7 .
6. Disconnect fuel return hose from fuel pressure regulator. Connect a separate hose to pressure regulator and insert hose end into a container. Turn ignition on. If fuel pressure is 38.4-44.0 psi (2.7-3.1 kg/cm 2 ), repair restriction in fuel return hose. If fuel pressure is not as specified, replace fuel pressure regulator and retest system.
7. If no fuel pressure is present, go to next step. If fuel pressure is present and is less than 38.4-44.0 psi (2.7-3.1 kg/cm 2 ), go to step 9 .
8. Using appropriate clamping pliers, pinch fuel return hose. Observe fuel pressure gauge as ignition switch is cycled on and off. If fuel pressure increases, replace fuel pressure regulator. If fuel pressure is not as specified, ensure there is an adequate supply of fuel in fuel tank. If fuel supply is adequate, check fuel pump and fuel pump circuits. See «FUEL PUMP CIRCUIT CHECK»(ref-158706-S22842602792003101500000) . If problem is found, repair as necessary. After repair, retest system.
9. Using appropriate clamping pliers, pinch fuel return hose. Observe fuel pressure gauge as ignition switch is cycled on and off. If fuel pressure is 63.9 psi (4.5 kg/cm 2 ) or more, replace fuel pressure regulator. If fuel pressure is not as specified, check for clogged fuel filter, restricted fuel feed hose, faulty fuel pump or fuel leakage at hose connection in fuel tank. If problem is found, repair as necessary. After repair, retest system.
10. Disconnect fuel return hose from pressure regulator. Connect a separate hose to pressure regulator and insert hose end into a container. Recheck fuel pressure. If fuel is discharged into container, replace fuel pressure regulator. If fuel does not discharge into container, check for leaking injector or fuel rail, faulty fuel pump check valve or leaking fuel pressure regulator diaphragm. If problem is found, repair as necessary. After repair, retest system.

Grand Vitara & XL-7)

1. Check fuel pressure as ignition switch is cycled on and off. See appropriate fuel pressure test under FUEL PRESSURE. If fuel pressure is 38.4-44.1 psi (2.7-3.1 kg/cm 2 ) and holds at 28.4 psi (2.0 kg/cm 2 ) or greater for one minute after fuel pump stops, go to next step. If fuel pressure is not present, go to step 3 . If fuel pressure is as specified, but does not hold, go to step 4 . If fuel pressure is low, go to step 5 . If fuel pressure is high, go to step 6 .
2. Start engine and allow it to reach normal operating temperature. If fuel pressure is 29.9-37.0 psi (2.1-2.6 kg/cm 2 ) with engine at idle, fuel pressure is okay. If fuel pressure is not as specified, check for clogged vacuum passage for fuel pressure regulator or faulty fuel pressure regulator. Repair as necessary and retest system.
3. Pinch fuel return hose. Turn ignition on. If fuel pressure increases, replace fuel pressure regulator. If fuel pressure is not as specified, go to «B-3: FUEL PUMP CIRCUIT INSPECTION»(ref-157312-S14054230572003080800000) . Repair as necessary and retest system.
4. Disconnect fuel return hose from pressure regulator. Connect a separate hose to pressure regulator and insert hose end into a container. Recheck fuel pressure. If fuel is discharged into container, replace fuel pressure regulator. If fuel does not discharge into container, check for leaking injector or fuel rail, faulty fuel pump check valve or leaking fuel pressure regulator diaphragm. Repair as necessary and retest system.
5. Pinch fuel return hose. Turn ignition on. If fuel pressure is 38.4 psi (2.7 kg/cm 2 ) or greater, replace fuel pressure regulator. If fuel pressure is not as specified, check for clogged fuel filter, restricted fuel feed hose, faulty fuel pump or fuel leakage at hose connection in fuel tank. Repair as necessary and retest system.
6. Disconnect fuel return hose from fuel pressure regulator. Connect a separate hose to pressure regulator and insert hose end into a container. Turn ignition on. If fuel pressure is 38.4-44.0 psi (2.7-3.1 kg/cm 2 ), repair restriction in fuel return hose. If fuel pressure is not as specified, replace fuel pressure regulator and retest system.

1. Check fuel pressure as ignition switch is cycled on and off. See appropriate fuel pressure test under FUEL PRESSURE. If fuel pressure is 35.6-42.7 psi (2.5-3.0 kg/cm 2 ) and holds at 25.6 psi (1.8 kg/cm 2 ) or greater for one minute after fuel pump stops, go to next step. If fuel pressure is not present, go to step 3 . If fuel pressure is as specified, but does not hold, go to step 4 . If fuel pressure is low, go to step 5 . If fuel pressure is high, go to step 6 .
2. Start engine and allow it to reach normal operating temperature. If fuel pressure is 29.8-37.0 psi (2.1-2.6 kg/cm 2 ) with engine at idle, fuel pressure is okay. If fuel pressure is not as specified, check for clogged vacuum passage for fuel pressure regulator or faulty fuel pressure regulator. Repair as necessary and retest system.
3. Pinch fuel return hose. Turn ignition on. If fuel pressure increases, replace fuel pressure regulator. If fuel pressure is not as specified, go to «B-3: FUEL PUMP CIRCUIT INSPECTION»(ref-157312-S14054230572003080800000) . Repair as necessary and retest system.
4. Disconnect fuel return hose from pressure regulator. Connect a separate hose to pressure regulator and insert hose end into a container. Recheck fuel pressure. If fuel is discharged into container, replace fuel pressure regulator. If fuel does not discharge into container, check for leaking injector or fuel rail, faulty fuel pump check valve or leaking fuel pressure regulator diaphragm. Repair as necessary and retest system.
5. Pinch fuel return hose. Turn ignition on. If fuel pressure is 64.0 psi (4.5 kg/cm 2 ) or greater, replace fuel pressure regulator. If fuel pressure is not as specified, check for clogged fuel filter, restricted fuel feed hose, faulty fuel pump or fuel leakage at hose connection in fuel tank. Repair as necessary and retest system.
6. Disconnect fuel return hose from fuel pressure regulator. Connect a separate hose to pressure regulator and insert hose end into a container. Turn ignition on. If fuel pressure is 35.6-42.7 psi (2.5-3.0 kg/cm 2 ), repair restriction in fuel return hose. If fuel pressure is not as specified, replace fuel pressure regulator and retest system.

FUEL PUMP

Remove fuel filler cap. Turn ignition on, while listening for fuel pump sounds. Fuel pump should run for 2 seconds and stop, every time ignition is cycled on and off. If fuel pump is not heard, perform appropriate procedure under FUEL PUMP CIRCUIT CHECK .

Fuel pressure pulses should be felt in fuel return line when ignition is cycled on and off. If pulses are not felt, perform appropriate procedure under FUEL PRESSURE .

1. Turn ignition on. If fuel pump is heard for 2 seconds, circuit is in good condition. If fuel pump is not heard, go to next step.
2. Turn ignition off. Remove fuel pump relay from underhood fuse/relay box. (Scheme 72) Check for poor, loose, corroded or damage to main relay socket connections. If problem is found, repair as necessary. If no problem is found, go to next step.
3. With ignition switch turned ON, measure voltage between engine ground and Black/Red wire terminals. If voltage is 10-14 volts, to next step. If voltage is not within specification, check ECM power and ground. If in good condition, Black/Red wire open or shorted to ground.
4. Check fuel pump relay. Refer to «FUEL PUMP RELAY & MAIN RELAY (AERIO)»(ref-158706-S21316284552003101500000). If relay is in good condition, go to next step. If not, replace relay.
5. With ignition switch turned OFF, disconnect connectors between floor harness and instrument harness. Connect fuel pump relay to relay/fuse box. Check for proper connection of Grey/Blue wire terminal at engine harness and Brown/Yellow wire terminal at instrument harness. If wire terminals are OK, measure voltage between connector G04 terminal No. 12 and vehicle body ground 3 seconds after ignition switch is turned ON. (Scheme 77) If voltage is 10-14 volts, go to next step. If voltage is not as specified, Brown/Yellow or Grey/Blue wire is open or shorted to ground.
6. Using same conditions as previous step, turn ignition switch ON and measure voltage within 3 seconds. If voltage is 0-1 volt, go to next step. If voltage is not as specified, substitute known-good ECM and recheck.
7. With ignition switch turned OFF, connect connectors between floor harness and instrument harness. Remove fuel tank and disconnect connector from fuel pump. Check resistance between Pink wire terminal and vehicle body ground. If resistance is infinity, go to next step. If resistance is not as specified, Pink wire is shorted to ground.
8. With ignition turned OFF, connect fused jumper wire between connector G04 terminal No. 12 and vehicle body ground. Turn ignition switch ON and measure voltage between Pink terminal at fuel pump connector and vehicle body ground. If voltage is 10-14 volts, go to next step. If voltage is not as specified, Pink wire is open.
9. Check for continuity between Black terminal at fuel pump and vehicle body ground with ignition switch OFF. If there is continuity, fuel pump is faulty. If there is no continuity, Black wire is open.

Scheme 81

1. Turn ignition on. If fuel pump is heard for 3 seconds, circuit is in good condition. If fuel pump is not heard, go to next step. CAUTION: Ensure jumper connections are made correctly. Improper connections may result in damage to PCM and wire harness.
2. Turn ignition off. Using a fused jumper wire, connect Pink/Black wire and Blue/Black wire terminals at fuel pump relay connector located on right side of engine compartment. Turn ignition on. If fuel pump is heard, go to next step. If fuel pump is not heard, check Pink/Black wire or Blue/Black wire for an open or poor connection. Repair as necessary. If wire and connections are okay, replace fuel pump and retest system.
3. Turn ignition off. Remove fuel pump relay. Using DVOM, measure resistance between fuel pump relay terminals. (Scheme 81) Continuity should not be present between relay terminals "A" and "B". On Vitara, resistance between relay terminals "C" and "D" should be 79-95 ohms at 68°F (20°C). On Grand Vitara and XL-7, resistance between relay terminals "C" and "D" should be 70-110 ohms at 68°F (20°C). Continuity should be present between relay terminals "A" and "B" as battery voltage and ground are applied to relay terminals "C" and "D". If resistance is as specified, go to next step. If resistance is not as specified, replace fuel pump relay and retest system.
4. Check for poor connection or open in Blue/Black wire or White/Green wire to fuel pump relay. Repair as necessary. If wire and connections are okay, replace PCM and retest system.

RELIEVING FUEL PRESSURE

1. Place transmission in Neutral (M/T) or Park (A/T). Set parking brake and block drive wheels. Disconnect fuel pump relay. Fuel pump relay is located in underhood fuse/relay box.
2. Remove fuel filler cap to release fuel vapor pressure in fuel tank. Reinstall fuel filler cap. Start engine and let run until it stalls. After engine stalls, crank engine 2-3 times for about 3 seconds to dissipate remaining fuel pressure in fuel lines. To restore normal operation, reinstall fuel pump relay.

IDLE CONTROL SYSTEM

Note. For ECM terminal identification, see PIN VOLTAGE/CIRCUIT RESISTANCE CHARTS article. For engine performance related component locations, see appropriate figure under COMPONENT LOCATIONS . For vacuum diagram identification, see VACUUM DIAGRAMS article.

FAST IDLE AIR VALVE

Note. A Thermo wax device which is incorporated as part of throttle body, may control a plunger or air bypass valve. When coolant temperatures are low 75-78°F (23-26°C) conditions for a higher than normal idle speed exist. As coolant temperatures raise, fast idle speed falls to a specified RPM, idle speed is then controlled by ECM/PCM and Idle Air Control (IAC) valve.

Aerio & Grand Vitara

Note. These models use thermo wax capsules to control a plunger and lever outside throttle body.

1. Check throttle valve lever moves freely. Measure plunger protrusion of fast idle control arm with coolant temperature at 77°F (25°C). (Scheme 82) Plunger measurement should be 1.048-1.078 in. (26.62-27.38 mm).
2. Start engine, check that higher than normal idle speed exists. As engine coolant temperature increases, fast idle speed should gradually reduce. As engine coolant temperatures reach 126-154°F (52-68°C), check to make sure fast control cam is off cam follower lever. (Scheme 83) If fast idle valve does not operate as specified, valve could be faulty or coolant passage could be blocked. If no problem is found with coolant passage, replace throttle body assembly.

Scheme 82

Scheme 83

Note. This model uses thermo wax to control an air bypass valve inside throttle body.

Ignition off, with coolant temperature at 75-78°F (23-26°C), disconnect Idle Air Control (IAC) valve. Start engine, check that higher than normal idle speed exist. As engine coolant temperatures raise, fast idle speed should gradually reduce. If results are as specified, fast idle air valve is in good condition. If not as specified, valve could be faulty or coolant passage could be blocked.

1. Turn ignition off. Disconnect IAC valve 2-pin harness connector. Measure resistance between IAC valve terminals. Resistance should be 8.6-10.6 ohms. Also, check continuity between IAC valve terminals and valve body. No continuity should be present. If measurements are as specified, go to next step. If measurements are not as specified, replace IAC valve.
2. Reconnect IAC valve harness connector. Start engine and run until it reaches normal operating temperature. Disconnect IAC valve connector and check idle RPM. Connect 12-volt battery negative terminal to IAC terminal No. 1. Connect 12-volt battery positive terminal to IAC terminal No. 2. (Scheme 84) If idle speed increases, IAC valve is okay. If idle speed does not increase, replace IAC valve.

Scheme 84

1. Remove IAC valve electrical connector. Using DVOM, check resistance of IAC valve between terminals No. 1 and 2, 2 and 3, 4 and 5, and 5 and 6. Resistance should be 35-43 ohms between each set of terminals. If resistance is as specified, go to next step. If resistance is not as specified, replace IAC valve and retest system.
2. Remove air cleaner hose and IAC valve. With electrical connector attached to IAC valve, crank engine for 2 seconds while observing valve. It should move once and then stop as soon as ignition is turned off. If IAC valve plunger does not move as specified, check for poor connections, open or short circuits in wiring. If electrical circuit is okay, replace IAC valve.

1. Remove IAC valve electrical connector. Using DVOM, check resistance of IAC valve between terminals "A" and "B", "B" and "C", "D" and "E", and "E" and "F". (Scheme 85) Resistance should be 20-24 ohms between each set of terminals at approximately 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace IAC valve and retest system.
2. Remove IAC valve from intake collector. With electrical connector attached to IAC valve, crank engine for 2 seconds while observing valve. It should move once and then stop as soon as ignition is turned off. If IAC valve plunger does not move as specified, check for poor connections, opens or shorts in wiring. If wiring is okay, replace IAC valve and retest system.

Scheme 85

1. Remove IAC valve electrical connector. Using DVOM, check resistance of IAC valve between terminals No. 1 and 2, 2 and 3, 4 and 5, and 5 and 6. (Scheme 86) Resistance should be 25.5-33.5 ohms between each set of terminals at approximately 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace IAC valve and retest system.
2. Remove IAC valve from throttle body. With electrical connector attached to IAC valve, crank engine for 2 seconds while observing valve. It should move once and then stop as soon as ignition is turned off. If IAC valve plunger does not move as specified, check for poor connections, opens or shorts in wiring. If wiring is okay, replace IAC valve and retest system.

Scheme 86

1. Check engine idle speed and Idle Air Control (IAC) duty cycle. See «IDLE SPEED & MIXTURE»(ref-157310-S04310283792003080800000) in ON-VEHICLE ADJUSTMENTS article. If idle speed is within specification, go to next step. If idle speed is not as specified, go to step 4 .
2. Turn headlights, heater blower and/or rear defogger on. If idle speed stays within specifications, system is okay. If idle speed drops below specification, go to step 5 .
3. For vehicles with power steering, check that idle speed is kept within specification even when the steering wheel is turned right or left until it stops. If idle speed stays within specification, system is in good condition. If not, check power steering pressure switch signal circuit. See «POWER STEERING PRESSURE SWITCH CIRCUIT CHECK (AERIO)»(ref-158706-S16889872002003101500000) . If check result is OK, go to step 5 .
4. Check air intake system for leaks or clogging. Also, check fast idle plunger adjustment. See «FAST IDLE AIR VALVE»(ref-158706-S25186211302003101500000) . If no problem is found, go to next step. If problem is found, repair as necessary. After repair, retest system.
5. Check IAC valve operation. See «IDLE AIR CONTROL VALVE OPERATION CHECK»(ref-158706-S15096799052003101500000) . If no problem is found, go to step 8 . If problem is found, go to next step.
6. Disconnect IAC valve 2-pin harness connector. Check for poor terminal connection at IAC valve harness connector. If problem is found, repair as necessary. After repair, retest system. If no problem is found, go to next step.
7. Measure resistance between IAC valve terminals. Resistance should be 8.6-10.6 ohms at 68°F (20°C). Measure resistance between terminals and IAC valve body. Resistance should be infinity. If resistance is as specified, go to next step. If resistance is not as specified, clean or replace IAC valve as necessary. After repair, retest system.
8. Check A/C input signal to ECM. See «A/C SIGNALS CIRCUIT CHECK»(ref-158706-S16779344502003101500000) under MISCELLANEOUS CONTROLS. If no problem is found, go to next step. If problem is found, repair as necessary. After repair, retest system.
9. Check for malfunction in following systems: High accessory engine load. EGR valve malfunction. EVAP system malfunction. Engine mechanical malfunction. Throttle position sensor malfunction. Engine coolant temperature sensor malfunction. PCV system malfunction. If no problem is found, go to next step. If problem is found, repair or replace as necessary. After repair, retest system.
10. Check engine idle speed and Idle Air Control (IAC) duty cycle. See «IDLE SPEED & MIXTURE»(ref-157310-S04310283792003080800000) in ON-VEHICLE ADJUSTMENTS article. If idle speed is within specification, testing is complete. If idle speed is not as specified, check for clogged idle air passages. If problem is found, repair as necessary. If no problem is found, substitute ECM with known good unit and retest system.

1. Check engine idle speed and Idle Air Control (IAC) duty cycle. See «IDLE SPEED & MIXTURE»(ref-157310-S04310283792003080800000). If idle speed is within specification, go to next step. If idle speed is not as specified, go to step 3.
2. Turn headlights on. If idle speed stays within specifications, system is okay. If idle speed drops below specification, go to next step.
3. Check IAC valve operation. See «IDLE AIR CONTROL VALVE»(ref-158706-S30889331512003101500000). If no problem is found, go to next step. If problem is found, check wire harness for open, short or poor coupler connections. If check is OK, substitute a known-good ECM (PCM) and recheck IAC valve operation.
4. If idle speed was not within specification in step 1, go to next step. If idle speed was within specification in step 1, check for the following: Vacuum leaks. Air inhaling. EVAP system malfunction. High accessory engine load. PCV system malfunction. Clogged idle air passage. MAF sensor malfunction. Throttle position sensor malfunction. Engine coolant temperature sensor malfunction. EGR valve malfunction. A/C signal malfunction. Transmission range switch signal malfunction.
5. If idle speed was higher than specification in step 1, go to next step. If not, go to step 9.
6. Check A/C input signal to ECM. See «A/C SIGNALS CIRCUIT CHECK»(ref-158706-S16779344502003101500000) under MISCELLANEOUS CONTROLS. If no problem is found, go to next step. If problem is found, repair as necessary. After repair, retest system.
7. Turn ignition switch ON and check voltage between ECM connector E61 terminal No. 30 and body ground. (Scheme 78) If voltage is 10-14 volts, go to next step. If voltage is not within specification, ABS signal circuit shorted to ground or ABS malfunction.
8. If IAC duty was less than about 2% in step 1, check for air leaks in intake manifold, throttle body, PCV valve and EVAP canister purge control system. If IAC duty was not less than 2% in step 1, check throttle position sensor and ECT sensor for performance. If sensors are OK, substitute a known-good ECM (PCM) and recheck.
9. Check transmission range switch signal. See «TRANSMISSION RANGE SENSOR»(ref-158706-S42908542962003101500000). If check results are satisfactory, go to next step. If results are not satisfactory, transmission range switch is malfunctioning or its circuits are open or short.
10. If IAC duty was more than about 30% in step 1, check parts or systems that can cause engine low idle. If IAC duty was not more then 30% in step 1, substitute a known-good ECM (PCM) and recheck.

1. Check engine idle speed and Idle Air Control (IAC) duty cycle. See «IDLE SPEED & MIXTURE»(ref-157310-S04310283792003080800000) . If idle speed is within specification, go to next step. If idle speed is not as specified, go to step 3 .
2. Turn headlights on. If idle speed stays within specifications, system is okay. If idle speed drops below specification, go to next step.
3. Check IAC valve operation. See «IDLE AIR CONTROL VALVE»(ref-158706-S30889331512003101500000) . If no problem is found, go to next step. If problem is found, check wire harness for open, short or poor coupler connections. If check is OK, substitute a known-good ECM (PCM) and recheck IAC valve operation.
4. If idle speed was not within specification in step 1 , go to next step. If idle speed was within specification in step 1 , check for the following: Vacuum leaks. Air inhaling. EVAP system malfunction. High accessory engine load. PCV system malfunction. Clogged idle air passage. MAF sensor malfunction. Throttle position sensor malfunction. Engine coolant temperature sensor malfunction. EGR valve malfunction. A/C signal malfunction. Transmission range switch signal malfunction.
5. If idle speed was higher than specification in step 1 , go to next step. If not, go to step 8 .
6. Check A/C input signal to ECM. See «A/C SIGNALS CIRCUIT CHECK»(ref-158706-S16779344502003101500000) under MISCELLANEOUS CONTROLS. If no problem is found, go to next step. If problem is found, repair as necessary. After repair, retest system.
7. If IAC duty was less than about 2% in step 1 , check for abnormal air inhaling from intake manifold, throttle body, PCV valve and EVAP canister purge control system. If IAC duty was not less than 2% in step 1 , check throttle position sensor and ECT sensor for performance. If sensors are OK, substitute a known-good ECM (PCM) and recheck.
8. Check transmission range switch signal. See «TRANSMISSION RANGE SENSOR»(ref-158706-S42908542962003101500000) . If check results are satisfactory, go to next step. If results are not satisfactory, transmission range switch is malfunctioning or its circuits are open or short.
9. If IAC duty was more than about 30% in step 1 , check parts or systems that can cause engine low idle. Check Fast Idle Air (FIA) valve. If IAC duty was not more then 30% in step 1 , substitute a known-good ECM (PCM) and recheck.

IGNITION SYSTEM

Note. For ECM terminal identification, see PIN VOLTAGE/CIRCUIT RESISTANCE CHARTS article. For engine performance related component locations, see appropriate figure under COMPONENT LOCATIONS . For vacuum diagram identification, see VACUUM DIAGRAMS article.

Aerio, Grand Vitara, Vitara & XL-7

For testing procedure, see IGNITION COIL ASSEMBLY INSPECTION in BASIC DIAGNOSTIC PROCEDURES article.

For testing procedures, see IGNITION TIMING in ON-VEHICLE ADJUSTMENTS article.

EMISSION SYSTEMS & SUB-SYSTEMS

Note. For ECM terminal identification, see PIN VOLTAGE/CIRCUIT RESISTANCE CHARTS article. For engine performance related component locations, see appropriate figure under COMPONENT LOCATIONS . For vacuum diagram identification, see VACUUM DIAGRAMS article.

EGR Valve

1. Turn ignition off. Connect scan tool to Data Link Connector (DLC). DLC is located under left side of instrument panel. Start engine and warm up to operating temperature. With engine at idle, select MISC. TEST parameter on scan tool and operate EGR valve. If engine RPM drops, EGR valve is okay. Go to DTC P0400: EXHAUST GAS RECIRCULATION (EGR) FLOW MALFUNCTION in appropriate SELF-DIAGNOSTICS article if other EGR system problems are suspected. If engine RPM did not drop, go to next step.
2. Turn ignition off. Remove EGR valve and inspect EGR passages for clogs. Clean out passages as necessary. Using DVOM, inspect EGR valve resistance between terminals. (Scheme 87)for terminal identification. See «EGR VALVE RESISTANCE»(ref-158706-S22340739572003101500000) table for specifications.

Scheme 87

EGR VALVE RESISTANCE

EVAP Canister

Remove hoses from EVAP canister. Locate port on canister that goes to fuel tank and blow air into it. There should be no restriction of air flow through canister PURGE pipe and AIR pipe. Plug PURGE and AIR pipes and try to blow into TANK port again. If able to blow air into TANK port, canister is leaking and must be replaced.

EVAP Canister Purge Valve Circuit

1. Disconnect purge valve vacuum hoses from vacuum pipes. Blow air into purge valve port "A". (Scheme 88) Air should not come out of port "B". If using scan tool, go to next step. If scan tool is not available, go to step 3.
2. Turn ignition off. Connect scan tool to Data Link Connector (DLC). DLC is located under left side of instrument panel. Turn ignition on. Select MISC TEST mode and use scan tool to turn EVAP canister purge valve on. Blow air into purge valve port "A". Air should now come out of port "B". If purge valve operates as described, purge valve and circuit are working properly. If operation is not as described, inspect for poor connections or open/short circuits in wiring between purge valve, ECM/PCM and fuse box. If wiring and connections are okay, go to «EVAP CANISTER PURGE VALVE»(ref-158706-S27819432102003101500000).
3. Turn ignition on. Using fused jumper wire, ground ECM/PCM terminal connector C46 terminal No. 6 on Aerio, C51-2 terminal No.17 on Vitara, C51-3 terminal No.1 on Grand Vitara, and C51-1 terminal No.15 on XL-7. See «PIN VOLTAGE/CIRCUIT RESISTANCE CHARTS»(ref-159417) article for ECM/PCM connector and terminal identification. Blow air into purge valve port "A". Air should now come out of port "B". If purge valve operates as described, purge valve and circuit are working properly. If operation is not as described, inspect for poor connections or open/short circuits in wiring between purge valve, ECM/PCM and fuse box. If wiring and connections are okay, go to «EVAP CANISTER PURGE VALVE»(ref-158706-S27819432102003101500000).

Scheme 88

1. Turn ignition off. Disconnect EVAP canister purge valve harness connector. Using an ohmmeter, measure resistance between terminals of purge valve. Resistance should be 30-34 ohms at 68°F (20°C) on Aerio, or 28-36 ohms at 68°F (20°C) on Grand Vitara, Vitara and XL-7. Resistance between each terminal and body of solenoid should be one megaohm or greater. If resistance is as specified, go to next step. If resistance is not as specified, replace EVAP canister purge valve. Retest system.
2. Disconnect vacuum hoses from solenoid. Blow into port "A". (Scheme 88) Air should not flow through solenoid. Using fused jumper wires, connect 12 volts and ground to solenoid terminals. Air should flow through port "B". If operation is not as specified, replace EVAP canister purge valve.

EVAP Canister Vent Valve Circuit

1. Disconnect air valve hose from vapor canister. Blow air into hose "A". (Scheme 89) Air should come out of hose "B". Replace air valve if operation is not as specified. If operation is as specified and a scan tool is available, go to next step. If scan tool is not available, go to step 3.
2. Turn ignition off. Connect scan tool to Data Link Connector (DLC). DLC is located under left side of instrument panel. Turn ignition on. Select MISC TEST and turn on EVAP canister air valve using scan tool. Blow air into hose "A". Air should no longer come out of hose "B". If operation of air valve is as described, EVAP canister air valve and circuit are okay. If operation is not as described, go to step 4.
3. Using a fused jumper wire, ground ECM/PCM connector G04 terminal No. 7 on Aerio, C51-2 terminal No.5 on Vitara, C51-3 terminal No.19 on Grand Vitara and C51-2 terminal No.18 on XL-7. See «PIN VOLTAGE/CIRCUIT RESISTANCE CHARTS»(ref-159417) article for ECM/PCM connector and terminal identification. Blow air into hose "A". Air should no longer come out of hose "B". If operation of air valve is as described, EVAP canister air valve and circuit are okay. If operation is not as described, go to next step.
4. Turn ignition off. Disconnect EVAP canister vent valve harness connector. Canister vent valve is located on top of EVAP canister. Using an ohmmeter, measure resistance between valve terminals. Resistance should be 25-30 ohms at 68°F (20°C). Resistance between each terminal and body of solenoid should be one megohm or greater. If resistance is as specified, go to next step. If resistance is not as specified, replace EVAP canister vent valve. Retest system.
5. Disconnect hoses from solenoid. Blow into port "A". (Scheme 89) Air should flow through valve. Use fused jumper wire to connect battery voltage and ground to air valve terminals. Air should not flow through port "B". If operation is not as specified, replace EVAP canister vent valve. If operation is as specified, inspect for poor connections or open/short circuits in wiring between EVAP canister vent valve, ECM/PCM and fuse box.

Scheme 89

EVAP Canister Vent Valve

1. Check EVAP canister vent valve for damage and check resistance of vent valve. Resistance should be 25-30 ohms at 68°F (20°C) between two terminals and 1 megohm or higher between terminal and valve body. If resistance is as specified, go to next step. If resistance is not as specified, replace vent valve.
2. Blow air into nozzle "A". Air should come out of nozzle "B". Connect 12 volt battery to valve terminals and blow air into nozzle "A". Air should not come out of nozzle "B". (Scheme 89) If result is not as specified, replace vent valve.

EVAP Canister Air Suction Filter

Check air suction filter for damage, contamination of mud or water. (Scheme 90)or (Scheme 91). If any damage or faulty condition is found, replace.

Scheme 90

Scheme 91

Refuel Vapor Control Valve (Aerio)

1. Check refuel vapor control valve for damage.
2. Apply 10 kPa (75 mmHg) vacuum to nozzle "A" while holding body with its upper cap facing downward and closing nozzle "B" with finger using vacuum pump gauge and check that vacuum is maintained at that level (there is no leakage). (Scheme 92) If vacuum leaks, replace.
3. Tilt refuel vapor control valve gradually while holding float in the body through hole "A" to keep it still. Then check that the valve on top of float moves smoothly. (Scheme 93) If found malfunctioning, replace.
4. Put refuel vapor control valve in kerosene and check that float moves smoothly to contact valve seat. (Scheme 94) If found malfunctioning, replace.

Scheme 92

Scheme 93

Scheme 94

Vapor Control Valve (Vitara, Grand Vitara & XL-7)

1. Check refuel vapor control valve for damage.
2. Put refuel vapor control valve in kerosene and check that float moves smoothly to contact valve seat. (Scheme 95) If found malfunctioning, replace.

Scheme 95

EVAP System Leakage Check

1. Disconnect purge hose from intake manifold and fuel tank pressure control valve hose from solenoid vacuum valve. Plug EVAP canister air valve hose end. Turn ignition off. Connect scan tool to Data Link Connector (DLC). DLC is located under left side of instrument panel. Select MISC TEST mode. Turn canister purge valve on using scan tool. If scan tool is not available, using fused jumper wire, ground ECM/PCM connector C46 terminal No 6 on Aerio, C51-2 terminal No.17 on Vitara, C51-2 terminal No.1 on Grand Vitara, and C51-1 terminal No.15 on XL-7. See «PIN VOLTAGE CHARTS»(ref-159417) article for ECM/PCM connector and terminal identification. Go to next step.
2. Connect vacuum pump to disconnected fuel tank pressure control valve hose. Apply 3.5 kPa (14.0 in.Aq.) to purge hose and seal it. After 15 seconds, vacuum should still be 3.3 kPa (13.6 in.Aq.) or more. If system does not meet specified results, leak is present in EVAP system. Locate leak using soapy water or leak detector.

Fuel Tank Pressure Control Valve

1. Disconnect hoses and remove fuel tank pressure control valve. Blow into TANK port. (Scheme 96) Air should flow out of CAN port smoothly when blown hard. If valve operates as specified, go to next step. If valve does not operate as specified, replace fuel tank pressure control valve and retest.
2. Blow air into CAN port. Air should come out of TANK port, even if blown softly. If valve operates as specified, go to next step. If valve does not operate as specified, replace fuel tank pressure control valve and retest.
3. Use vacuum pump attached at vacuum port to open valve. Blow into TANK port. Air should freely flow out of CAN port. If valve does not operate as specified, replace fuel tank pressure control valve and retest.

Scheme 96

Fuel Tank Pressure & Temperature Sensor

1. Remove fuel tank pressure and temp. sensor from fuel tank. Check sensor air vent hole and pressure passage for clog. Clean if clogged. Check sensor O-ring for damage and deterioration. (Scheme 97) Replace as necessary.
2. Arrange 3 new 1.5-volt batteries in series (check that total voltage is 4.5-5.0 volts) and connect its positive terminal to "A" terminal of tank pressure and temp. sensor and negative terminal to "B" terminal. Then check voltage between "C" and "B". Also, check if voltage reduces when vacuum is applied up to 6.6 kPa (50 mmHg) by using vacuum pump and if it increases when positive pressure applied up to 6.6 kPa (50 mmHg) by using hand pump. (Scheme 98) If measured voltage doesn't shown such characteristic as shown in the figure, replace fuel tank pressure and temp. sensor. CAUTION: As connection to wrong terminal will cause damage to tank pressure and temp. sensor, make absolutely sure to connect properly as shown. (Scheme 98) Do not apply pressure higher than 98 kPa (742 mmHg) to tank pressure and temp. sensor by hand pump. Applying excessive pressure will break it.
3. Immerse temperature sensing part of fuel tank pressure and temp. sensor in water (or ice) and measure resistance between sensor terminal "A" and "B" while heating water gradually. (Scheme 99) If measured resistance doesn't show such characteristic as shown in the figure, replace Fuel Tank pressure and temperature sensor.

Scheme 97

Scheme 98

Scheme 99

Fuel Tank Pressure Control Solenoid Valve Circuit

1. On Vitara, disconnect vacuum hose from fuel tank pressure control solenoid valve (FTPCSV). Start engine and run at idle. Check for vacuum at hose from intake manifold. If vacuum is not present, repair or replace clogged vacuum hose or vacuum passage. If vacuum is present, turn engine off and go to next step.
2. Blow into port "A". (Scheme 100) Air should come out of filter and not port "B". Turn ignition off. Connect scan tool to Data Link Connector (DLC). DLC is located under left side of instrument panel. Turn ignition on. Select MISC TEST mode and use scan tool to turn FTCPSV on. If scan tool is not available, remove ECM/PCM cover and using fused jumper wire, ground ECM/PCM harness connector terminal C51-2 terminal No. 6 on Vitara. Blow into port "A" again. Air should now come out of port "B" and not filter. If operation is as specified, FTPCSV, wiring and connections are okay. If operation is not as specified, go to «FUEL TANK PRESSURE CONTROL SOLENOID VALVE (FTPCSV)»(ref-158706-S09902772402003101500000).

Scheme 100

1. Turn ignition off. Disconnect FTPCSV harness connector. Using an ohmmeter, measure resistance between terminals of FTPCSV. Resistance should be 28-36 ohms on Vitara at 68°F (20°C). Resistance between each terminal and body of solenoid should be one megohm or greater. If resistance is as specified, go to next step. If resistance is not as specified, replace FTPCSV. Retest system.
2. Blow into port "A". Air should flow out of filter. (Scheme 100) Use fused jumper wires to connect battery voltage and ground to solenoid valve terminals. Blow into port "A". Air should flow out of port "B" and not to filter. If FTPCSV operates as specified, check for an open or short circuit between FTPCSV, ECM/PCM and main relay. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If FTPCSV does not operate as specified, replace FTPCSV.

POSITIVE CRANKCASE VENTILATION

Disconnect PCV valve from valve cover. Start engine and let idle. Check for vacuum at PCV valve. If vacuum is not present, disconnect PCV valve from hose. If engine runs rough or stalls, replace PCV valve. If engine does not run rough or stall, check for restriction in PCV hose. Repair as necessary. Shake valve and listen for rattle. Replace PCV valve if no rattle is heard.

MISCELLANEOUS CONTROLS

Note. For ECM terminal identification, see PIN VOLTAGE/CIRCUIT RESISTANCE CHARTS article. For engine performance related component locations, see appropriate figure under COMPONENT LOCATIONS . For vacuum diagram identification, see VACUUM DIAGRAMS article.

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

1. With ignition switch OFF, disconnect ECM connectors and check resistance between ECM connector G04 terminal No. 20 and 18 & terminal No. 6 and 18. (Scheme 77) Resistance should be 6.3-6.9 k/ohms at 32°F (0°C) and 1.8-2.2 k/ohms at 77°F (25°C). If resistance is within specification, go to next step. Is resistance is not as specified, A/C evaporator temperature sensor or its circuits are faulty.
2. Measure voltage at ECM connector G04 terminal No. 28. Voltage should be 10-14 volts with ignition switch ON and A/C switch OFF. With ignition switch ON and A/C switch ON, voltage should be 0-1 volt. If voltage is as specified, go to next step. If voltage is not as specified, check Green/Black wire for open or short. Check ECM connector G04 terminal No. 28 for poor connection. If wire and connector are fine, substitute a known-good ECM and recheck.
3. Turn blower switch ON. If A/C cooling fan starts, go to step 7. If A/C cooling fan does not start, go to next step.
4. Measure voltage at ECM connector G04 terminal No. 32. Voltage should be 10-14 volts with ignition switch ON and A/C switch OFF. With ignition switch ON and A/C switch ON, voltage should be 0-1 volt. If voltage is as specified, go to next step. If voltage is not as specified, check Blue/Yellow wire for open or short. Check ECM connector terminal No. 32 for poor connection. If wire and connector are fine, substitute a known-good ECM and recheck.
5. With ignition switch OFF, remove A/C condenser fan control relay. Check for proper connection to relay at terminals 1 and 2. If Okay, check for continuity between 1 and 2 when battery is connected to terminals 3 and 4. (Scheme 73)If check result is satisfactory, go to next step. If result is not satisfactory, replace A/C condenser fan control relay.
6. With ignition turned OFF, disconnect A/C condenser fan motor connector and Check for proper connection at Red/Blue and Black terminals. If OK, connect battery to motor and check for operation. If motor is in good condition, Red/Blue or Black circuit open. If motor is not in good condition, replace A/C condenser fan motor.
7. Turn A/C switch and heater blower switch ON. IF A/C compressor starts, A/C control system is in good condition. If A/C compressor does not start, go to next step.
8. Measure voltage at ECM connector C45 terminal No. 21. With engine running and A/C switch OFF, voltage should be 10-14 volts. With engine running and A/C switch ON, voltage should be 0-1 volt. If voltage is not as specified, check Brown/Yellow wire for open or short. Check ECM connector G04 terminal No. 28 for poor connection. If wire and connector are fine, substitute a known-good ECM and recheck.
9. With ignition switch OFF, remove A/C compressor control relay. Check for proper connection to relay at terminals 1 and 2. If OK, check for continuity between 1 and 2 when battery is connected to terminals 3 and 4. (Scheme 73) If check result is satisfactory, check A/C compressor. If result is not satisfactory, replace A/C compressor control relay.

1. Turn ignition on. Backprobing at ECM, measure voltage between ground and ECM connector E61 terminal No. 28 (Yellow/Black wire). (Scheme 101) With A/C and blower switch Off, voltage should be 10-14 volts. With A/C and blower switch On, voltage should be 0-1.5 volts. If voltage readings are as specified, go to next step. If voltage readings are not as specified, check for open or short in Yellow/Black wire between ECM and A/C control module. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If no problem with wiring is found, check for A/C malfunction. See appropriate MANUAL or AUTOMATIC A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING.
2. Turn ignition on. Backprobing at ECM, measure voltage between ground and ECM connector E61 terminal No. 27 (Grey/White wire). With A/C and blower switch Off, voltage should be 0-1 volt. With A/C and blower switch On, voltage should be 10-14 volts. If voltage readings are as specified, A/C circuit s are okay. If voltage readings are not as specified, go to next step.
3. Check for open or short in Grey/White or Grey/Yellow wire between A/C control module and ECM. (Scheme 101) Also, check for poor performance of ECT sensor, TP sensor, engine start signal input to ECM. For testing procedures, see appropriate DTC testing procedure in SELF DIAGNOSTICS - GRAND VITARA article. If problem is found, repair as necessary. After repair, retest system. If no problem with wiring or sensors is found, substitute ECM with known good unit and retest system.

Scheme 101

1. Turn ignition on. Backprobing at ECM, measure voltage between ground and ECM connector E61 terminal No. 17 (Yellow/Black wire). (Scheme 102) With A/C and blower switch Off, voltage should be 10-14 volts. With A/C and blower switch On, voltage should be 0-1.5 volts. If voltage readings are as specified, go to next step. If voltage readings are not as specified, check for open or short in Yellow/Black wire between ECM and A/C control module. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If no problem with wiring is found, check for A/C malfunction. See appropriate MANUAL or AUTOMATIC A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING.
2. Turn ignition on. Backprobing at ECM, measure voltage between ground and ECM connector E61 terminal No. 8 (Grey/White wire). With A/C and blower switch Off, voltage should be 0-1 volt. With A/C and blower switch On, voltage should be 10-14 volts. If voltage readings are as specified, A/C circuit s are okay. If voltage readings are not as specified, go to next step.
3. Check for open or short in Grey/White or Grey/Yellow wire between A/C amplifier and ECM. (Scheme 102) Also, check for poor performance of ECT sensor, TP sensor, engine start signal input to ECM. For testing procedures, see appropriate DTC testing procedure in appropriate SELF DIAGNOSTICS article. If problem is found, repair as necessary. After repair, retest system. If no problem with wiring or sensors is found, substitute ECM with known good unit and retest system.

Scheme 102

POWER STEERING PRESSURE SWITCH CIRCUIT CHECK (AERIO)

1. If scan tool is not available, go to next step. Turn ignition off. Connect scan tool to Data Link Connector (DLC). DLC is located under left side of instrument panel. Start engine. On scan tool, select DATA LIST and observe POWER STEERING PRESSURE SWITCH parameter. With engine running and steering wheel in straight ahead position, parameter should read OFF and voltage should be 10-14 volts. With engine running and steering wheel turned right or left, parameter should read ON and voltage should be 0-1 volt. If parameter and voltage readings are as specified, power steering signal circuit is okay. If parameter and voltage readings are not as specified, go to step 3.
2. Turn ignition on. Backprobing at ECM, measure voltage between ground and ECM connector C46 terminal No. 17 (Yellow wire). (Scheme 77) With engine running and steering wheel in straight ahead position, voltage should be 10-14 volts. With engine running and steering wheel turned right or left, voltage should be 0-1 volt. If parameter and voltage readings are as specified, power steering signal circuit is okay. If parameter and voltage readings are not as specified, go to next step.
3. Turn ignition off. Disconnect Power Steering Pressure (PSP) switch harness connector. Turn ignition on. Measure voltage between ground and PSP switch harness connector. If voltage reading is 10-14 volts, PSP switch or power steering is malfunctioning. Repair or replace as necessary. If voltage reading is not as specified, go to next step.
4. Check for open or short to ground in Yellow wire between PSP switch and ECM. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Also, check for poor terminal connections at PSP switch and ECM. If problem is found, repair as necessary. After repair, retest system. If no problem with wiring or switch is found, substitute ECM with known good unit and retest system.