Engine Controls - Basic Diagnostic Procedures: Other Suzuki Vitara I

Compression

Note. Before checking engine compression test ensure engine oil and coolant level is correct, battery is fully charged and starter motor is operating properly.

Check engine mechanical condition using a compression gauge, vacuum gauge or an engine analyzer. See engine analyzer manual for specific instructions. Ensure engine is at normal operating temperature. Engine cranking speed must be at least 250 RPM during compression test. Check compression pressure at all cylinders as follow

1. Start engine and allow it to reach normal operating temperature. Turn ignition switch to LOCK position.
2. Disable fuel injectors by disconnecting fuel injector main harness connectors. (Scheme 3) Remove ignition coils and spark plugs. See «SPARK PLUGS & IGNITION COIL ASSEMBLY»(ref-157824-S40644651432003082700000) under IGNITION SYSTEM in REMOVAL & INSTALLATION article.
3. Install compression gauge into spark plug hole. (Scheme 4) For vehicles equipped with (M/T) depress clutch pedal. Depress accelerator pedal to fully open throttle position. Crank engine and read the highest pressure on compression gauge. Compression should be within specification. See «COMPRESSION SPECIFICATIONS»(ref-157312-S27919960092003080800000) table. Carry out this step for each cylinder.

Scheme 3

Scheme 4

COMPRESSION SPECIFICATIONS

Vacuum

Engine vacuum that is developed in intake line is a good indicator of engine condition. Perform engine vacuum check as follow

1. Set transmission shifter lever in "Neutral" position ("P" range for A/T model), set parking brake and block drive wheels. Start engine and allow it to reach normal operating temperature. Ensure that engine idle speed is within specification. See «IDLE SPEED & MIXTURE»(ref-157310-S04310283792003080800000) in ON-VEHICLE ADJUSTMENT article.
2. Turn ignition switch to LOCK position. Disconnect vacuum hose and connect vacuum gauge and 3-way joint hose between vacuum hose and intake manifold (Aerio and Vitara). (Scheme 5) Disconnect vacuum hose and connect vacuum gauge and 3-way joint hose between vacuum hose and fuel pressure regulator valve (Grand Vitara and XL-7). (Scheme 5)
3. Start engine and let it idle. Read vacuum gauge, vacuum should be within specification. See «VACUUM SPECIFICATION»(ref-157312-S42455583672003090300000) table. If vacuum is not as specified, check engine compression. See «COMPRESSION»(ref-157312-S26769249702003080800000). Also check exhaust backpressure. See «EXHAUST SYSTEM BACKPRESSURE»(ref-157312-S28869455082003080800000).

Scheme 5

VACUUM SPECIFICATION

Exhaust System Backpressure

1. Exhaust system backpressure can be checked with a vacuum or pressure gauge. If using a pressure gauge, remove oxygen sensor. Connect a 0-5 psi (0-0.35 kg/cm 2 ) pressure gauge and run engine at 2500 RPM. If exhaust system backpressure is greater than 2 psi (0.14 kg/cm 2 ), exhaust system or catalytic converter is plugged.
2. If using a vacuum gauge, connect vacuum gauge hose to intake manifold vacuum port. (Scheme 5) Start engine and allow it to reach normal operating temperature. Observe vacuum gauge while opening throttle part way and holding steady. If vacuum gauge reading slowly drops after stabilizing, exhaust system should be checked for a restriction.

FUEL SYSTEM

Note. For diagnosis of a no-start or rough running condition related to a fuel system problem, go to CIRCUIT TESTS .

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 engine compartment relay box (Aerio), and under left side of dash panel (Grand Vitara, Vitara and XL-7). (Scheme 6)- (Scheme 8).
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.

Scheme 6

Scheme 7

Scheme 8

FUEL PRESSURE

Note. If fuel pressure is not as specify, perform fuel filter inspection. For fuel filter location, removal & installation, see FUEL FILTER under FUEL SYSTEM in REMOVAL & INSTALLATION article. If fuel filter check okay, check fuel pump. See FUEL PRESSURE TEST .

Fuel System Circuit

Turn ignition switch to ON position leaving engine OFF. Fuel pump should operate for 3 seconds. If fuel pump does not operate, check fuses, fuel pump relay, fuel pump, all system electrical connections and PCM. See CIRCUIT TESTS .

IGNITION CHECKS

Note. To diagnose a no-spark condition, perform all procedures listed under IGNITION CHECKS.

Aerio, Grand Vitara, Vitara & XL-7

1. Turn ignition switch to LOCK position. Disable fuel injectors by disconnecting fuel injector main harness connectors. (Scheme 3) Remove ignition coils and spark plugs. See «SPARK PLUGS & IGNITION COIL ASSEMBLY»(ref-157824-S40644651432003082700000) under IGNITION SYSTEM in REMOVAL & INSTALLATION article. Inspect spark plugs for fouling or improper gap. Repair as necessary.
2. Connect spark plugs to ignition coils and reconnect ignition coils harness connectors. Ground spark plugs. Have an assistant depress clutch pedal (M/T) and crank engine. Check for strong blue spark at spark plug. If spark is not present, check for faulty spark plug. If spark plug is okay, check ignition coil resistance. See «IGNITION COIL RESISTANCE»(ref-157312-S00519516882003080800000).

Ignition system is equipped with Distributorless Ignition System (DIS). Each cylinder has its own ignition coil with a built-in igniter (no secondary wire is used). For ignition coils assembly testing, see IGNITION COIL ASSEMBLY INSPECTION .

Ignitor is an integral part of ignition coil. See IGNITION COIL ASSEMBLY INSPECTION for test procedures.

Note. This is a visual inspection only. No other test procedure is available from manufacturer.

Check ignition coil assembly for following possible malfunctions

1. Damage.
2. Deterioration.
3. Terminal corrosion.

If any malfunction is found, repair as necessary.

Grand Vitara, Vitara & XL-7

Disconnect harness connector from noise suppressor, taped to main engine wiring harness. (Scheme 9) Using DVOM, ensure continuity is not present between terminals "A" and "B". (Scheme 10) If test result is not within specification, replace noise suppressor.

Scheme 9

Scheme 10

CAMSHAFT POSITION SENSOR

For Camshaft Position (CMP) sensor testing, perform related DTC testing procedure. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in appropriate SELF DIAGNOSTICS article.

CRANKSHAFT POSITION SENSOR

For Crankshaft Position (CKP) sensor testing, perform related DTC testing procedure. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in appropriate SELF DIAGNOSTICS article.

IDLE SPEED & IGNITION TIMING

Note. Idle speed is adjustable only on Aerio model.

Note. On all models, Suzuki scan tool is used to disable computer and check base timing. Timing is adjustable on all models, if timing is out of specification, check system related parts and readjust timing.

Note. Ensure ignition timing advances as engine speed increases.

Ensure idle speed and base ignition timing are set to specification. See IDLE SPEED SPECIFICATIONS and IGNITION TIMING tables. If necessary, see ON-VEHICLE ADJUSTMENTS article for adjustment procedures. If scan tool is available, check for correct IAC duty. See IAC DUTY AT SPECIFIED IDLE SPEED table.

IDLE SPEED SPECIFICATIONS

IAC DUTY AT SPECIFIED IDLE SPEED

IGNITION TIMING (Degrees BTDC @ RPM)

Scheme 11

Scheme 12

Scheme 13

Scheme 14

Scheme 15

CIRCUIT TESTS

Note. See PIN VOLTAGE/CIRCUIT RESISTANCE CHARTS article and ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL for PCM connector and wire terminal identification.

CIRCUIT TEST DIRECTORY

1. Perform customer complain analysis as follow: Record details of problem (failure, complain) and how it occurred as described by customer. For this purpose, use of an inspection form will facilitate collecting information to the point required for proper analysis and diagnose. After performing customer complain analysis, go to next step.
2. Retrieve, record and clear DTCs and freeze frame data. See SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article. If any DTC is retrieved, go to next step. If no DTC is retrieved, go to step 4 .
3. Perform a visual inspection. See «VISUAL INSPECTION»(ref-157312-S05956516382003080800000) under PRELIMINARY INSPECTION. If no malfunction is found, go to step 5 . If malfunction is found, repair or replace a necessary and go to step 11 .
4. Perform a visual inspection. See «VISUAL INSPECTION»(ref-157312-S05956516382003080800000) under PRELIMINARY INSPECTION. If no malfunction is found, go to step 8 . If malfunction is found, repair or replace a necessary and go to step 11 .
5. Perform trouble symptom confirmation as follow: Based on information recorded in step 1 and 2 , confirm trouble symptoms. Also, reconfirm DTC described in each DTC diagnosis. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in appropriate SELF-DIAGNOSTICS article. If trouble symptom is identified, go to next step. If trouble symptom is not identified, go to step 7 .
6. Re-retrieve and record DTCs and freeze frame data. See SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article. If no DTC is retrieved, go to step 8 . If any DTC is retrieved, go to step 9 .
7. Re-retrieve and record DTCs and freeze frame data. See SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article. If any DTC is retrieved, go to step 9 . If no DTC is retrieved, go to step 10 .
8. Check and repair complain described by customeraccording to «TROUBLE SHOOTING - NO-CODES»(ref-158314) article. After malfunction was repaired, go to step 11 .
9. Check and repair malfunction according to appropriate DTC test. See DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article. After malfunction was repaired, go to step 11 .
10. Check for intermittent problem. See «INTERMITTENTS»(ref-158314-S36733713052003092200000) in TROUBLE SHOOTING - NO CODES article. After malfunction is found and repair is performed, go to next step.
11. Perform final confirmation test as follow: Confirm that problem is not present and engine is free from any abnormal conditions. If what has been repaired is related to DTCs, clear DTCs and perform self-diagnostics. See SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS.

Aerio

Note. Perform all voltage and resistance tests using a Digital Volt-Ohm Meter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens.

1. Using a mechanic's stethoscope, check each fuel injector for operating "clicking" sound as engine is cranked or running. see scheme 4 If any one or all fuel injectors do not make operating sound, go to next step. If all fuel injectors made operating sound, fuel injector circuit is okay.
2. Turn ignition switch to LOCK position. Disconnect suspect fuel injector(s) 2-pin harness connector(s). (Scheme 16) Check fuel injector(s) harness connector(s) for poor, loose corroded or damaged connector terminals. If connector and terminals are okay, go to next step. If connector or terminals are faulty, repair or replace as necessary. After repair, retest system for normal operation.
3. Using DVOM, measure continuity between all fuel injectors connector terminals No. 1 and 2 and fuel injector body (component side). If continuity is not found, go to next step. If continuity is found, replace fuel injector. See «FUEL RAILS & INJECTORS»(ref-157824-S28405279342003082700000) underFUEL SYSTEM in REMOVAL & INSTALLATION article. After repair, retest system for normal operation.
4. Turn ignition switch to ON position. Using DVOM, measure voltage between ground and fuel injector(s) harness connector terminal No. 2 (Blue/Black wire). (Scheme 16) See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If voltage is 10-14 volts, go to next step. If voltage is less than 10 volts, check for open or short circuit in Blue/Back wire between fuel injector and main relay. After repair, retest system for normal operation.
5. Turn ignition switch to LOCK position. Disconnect ECM 28-pin harness connector C46. ECM is located under instrument panel, behind glove box. (Scheme 17) Using DVOM, measure resistance between ground specified ECM connector terminal. See «CHECKING CIRCUITS BETWEEN FUEL INJECTOR & ECM»(ref-157312-S42531422352003090500000) table. (Scheme 18) See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If resistance is infinity, go to next step. If any resistance is found, repair faulty circuit for short to ground between fuel injector and ECM. After repair, retest system for normal operation. CHECKING CIRCUITS BETWEEN FUEL INJECTOR & ECM ECM Connector Terminal No. Wire Color C46 20 (Blue/Yellow) C46 8 (Blue/White) C46 1 (Blue/Red) C46 2 (Blue/Green)
6. Turn ignition switch to ON position. Using DVOM, measure voltage between ground and specified ECM connector terminal. See «CHECKING CIRCUITS BETWEEN FUEL INJECTOR & ECM»(ref-157312-S42531422352003090500000) table. (Scheme 18) See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If voltage is zero volts, go to next step. If any voltage is found, repair appropriate faulty circuit for short to power between fuel injector and ECM. After repair, retest system for normal operation.
7. Turn ignition switch to LOCK position. Connect ECM and all fuel injector connectors. Turn ignition switch to ON position. Backprobe and measure voltage between ground and specified ECM connector terminal. See «CHECKING CIRCUITS BETWEEN FUEL INJECTOR & ECM»(ref-157312-S42531422352003090500000) table. (Scheme 18) See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If voltage is 10-14 volts, perform fuel injector component test. See FUEL INJECTORS under FUEL SYSTEM in SYSTEM & COMPONENT TESTING article. If any fuel injector is faulty, replace as necessary. If fuel injectors are okay, substitute ECM with known good module. See «ENGINE CONTROL MODULE»(ref-157824-S39119365112003082700000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. If voltage is less than 10 volts, repair open circuit at appropriate wire between fuel injector and ECM. After repair, retest system for normal operation.

Scheme 16

Scheme 17

Scheme 18

Grand Vitara

Note. Perform all voltage and resistance tests using a Digital Volt-Ohm Meter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens.

1. Using a mechanic's stethoscope, check each fuel injector for operating "clicking" sound as engine is cranked or running. see scheme 4 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 switch to LOCK position, Disconnect ECM 28-pin harness connector C51-2. ECM is located under instrument panel, behind glove box. (Scheme 17) Using DVOM, measure resistance at specified circuit between ECM connector terminals. See «CHECKING FUEL INJECTOR CIRCUIT RESISTANCE»(ref-157312-S14494266792003090800000) table. (Scheme 19) See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Resistance should be 10-14 ohms. If resistance is not as specified, go to next step. If resistance is as specified, fuel injector circuit is okay. CHECKING FUEL INJECTOR CIRCUIT RESISTANCE ECM Connector/Terminal (Wire Color) ECM Connector/Terminal (Wire Color) C51-2/7 (Pink) C51-2/20 (Blue/Black) C51-2/6 (Pink/Black) C51-2/20 (Blue/Black) C51-2/19 (Pink/Green) C51-2/20 (Blue/Black) C51-2/18 (Pink/Blue) C51-2/20 (Blue/Black) C51-2/28 (Gray/Green) C51-2/20 (Blue/Black) C51-2/27 (Gray/Black) C51-2/20 (Blue/Black)
3. Connect ECM connector. Turn ignition switch to ON position. Backprobe and measure voltage between ground and specified ECM connector and terminal. See «CHECKING CIRCUITS BETWEEN FUEL INJECTOR & ECM»(ref-157312-S20231615122003090800000) table. (Scheme 19) See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If voltage is 10-14 volts, substitute ECM with known good module. See «ENGINE CONTROL MODULE»(ref-157824-S39119365112003082700000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article. If voltage is less than 10 volts, repair open circuit in Blue/Black wire between fuel injector and ECM. After repair, retest system for normal operation. CHECKING CIRCUITS BETWEEN FUEL INJECTOR & ECM ECM Connector Terminal No. Wire Color C51-2 7 (Pink) C51-2 6 (Pink/Black) C51-2 19 (Pink/Green) C51-2 18 (Pink/Blue) C51-2 28 (Gray/Green) C51-2 27 (Gray/Black)

Scheme 19

Vitara

Note. Perform all voltage and resistance tests using a Digital Volt-Ohm Meter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens.

1. Using a mechanic's stethoscope, check each fuel injector for operating "clicking" sound as engine is cranked or running. see scheme 4 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 switch to LOCK position, Disconnect ECM harness connectors C51-2 and C51-3. ECM is located under instrument panel, behind glove box. (Scheme 17) Using DVOM, measure resistance at specified circuit between ECM connector terminals. See «CHECKING FUEL INJECTOR CIRCUIT RESISTANCE»(ref-157312-S05166219522003090800000) table. (Scheme 20)- (Scheme 21). See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Resistance should be 13-16 ohms at 20 °C (68 °F). If resistance is as specified, fuel injector circuit is okay. If resistance is not as specified, repair short between fuel injectors circuit wires, between fuel injector and ECM. After repair, retest system for normal operation. CHECKING FUEL INJECTOR CIRCUIT RESISTANCE ECM Connector/Terminal (Wire Color) ECM Connector/Terminal (Wire Color) C51-2/2 (Pink) C51-3/4 (Blue/Black) C51-2/1 (Pink/Black) C51-3/4 (Blue/Black) C51-2/9 (Pink/Green) C51-3/4 (Blue/Black) C51-2/8 (Gray/Blue) C51-3/4 (Blue/Black)
3. If all fuel injectors do not make operating sound, go to next step. If any fuel injector does not make operating sound, check fuel injector(s) harness connector(s) for poor, loose corroded or damaged connector terminals. If connectors and terminals are okay, perform fuel injector component test. See «FUEL INJECTORS»(ref-158706-S07976492952003101500000) under FUEL SYSTEM in SYSTEM & COMPONENT TESTING article. If connectors and terminals are faulty, repair or replace as necessary. After repair, retest system for normal operation.
4. Disconnect all fuel injectors 2-pin harness connector. Using DVOM, measure voltage at all fuel injector connectors terminals No. 2 (Blue/Black wire). (Scheme 22) See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If voltage is 10-14 volts, perform fuel injector component test. See «FUEL INJECTORS»(ref-158706-S07976492952003101500000) under FUEL SYSTEM in SYSTEM & COMPONENT TESTING article. If voltage is less than 10 volts, repair open or short circuit in Blue/Black wire between appropriate fuel injector and main relay. After repair, retest system for normal operation.

Scheme 20

Scheme 21

XL-7

Note. Perform all voltage and resistance tests using a Digital Volt-Ohm Meter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens.

1. Using a mechanic's stethoscope, check each fuel injector for operating "clicking" sound as engine is cranked or running. see scheme 4 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 switch to LOCK position, Disconnect ECM harness connectors C51-2 and C51-3. ECM is located under instrument panel, behind glove box. (Scheme 17) Using DVOM, measure resistance at specified circuit between ECM connector terminals. See «CHECKING FUEL INJECTOR CIRCUIT RESISTANCE»(ref-157312-S32131354662003090800000) table. (Scheme 20)- (Scheme 21). See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Resistance should be 14.2-14.8 ohms at 20 °C (68 °F). If resistance is as specified, fuel injector circuit is okay. If resistance is not as specified, repair short between fuel injectors circuit wires, between fuel injector and ECM. After repair, retest system for normal operation. CHECKING FUEL INJECTOR CIRCUIT RESISTANCE ECM Connector/Terminal (Wire Color) ECM Connector/Terminal (Wire Color) C51-2/2 (Pink) C51-3/4 (Blue/Black) C51-2/1 (Pink/Black) C51-3/4 (Blue/Black) C51-2/9 (Pink/Green) C51-3/4 (Blue/Black) C51-2/8 (Gray/Blue) C51-3/4 (Blue/Black) C51-2/22 (Gray/Green) C51-3/4 (Blue/Black) C51-2/21 (Gray/Black) C51-3/4 (Blue/Black)
3. If all fuel injectors do not make operating sound, go to next step. If any fuel injector does not make operating sound, check fuel injector(s) harness connector(s) for poor, loose corroded or damaged connector terminals. If connectors and terminals are okay, perform fuel injector component test. See «FUEL INJECTORS»(ref-158706-S07976492952003101500000) under FUEL SYSTEM in SYSTEM & COMPONENT TESTING article. If connectors and terminals are faulty, repair or replace as necessary. After repair, retest system for normal operation.
4. Disconnect all fuel injectors 2-pin harness connector. Using DVOM, measure voltage at all fuel injector connectors terminals No. 2 (Blue/Black wire). (Scheme 22) See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If voltage is 10-14 volts, perform fuel injector component test. See «FUEL INJECTORS»(ref-158706-S07976492952003101500000) under FUEL SYSTEM in SYSTEM & COMPONENT TESTING article. If voltage is less than 10 volts, repair open or short circuit in Blue/Black wire between appropriate fuel injector and main relay. After repair, retest system for normal operation.

Note. Perform all voltage and resistance tests using a Digital Volt-Ohm Meter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens.

1. Using a mechanic's stethoscope at gas tank, check for fuel pump operation sound when ignition switch is turned ON. If fuel pump operation sound is heard for 3 second and stop, circuit is in good condition. If fuel pump is not heard, go to next step.
2. Turn ignition switch to LOCK position. Disconnect fuel pump relay from relay/fuse box, located in engine compartment. (Scheme 6) Ensure is proper connection at each terminal of fuel pump relay, repair as necessary. Turn ignition switch to ON position. Measure voltage between ground and fuel pump relay/fuse box connector C07 terminals No. 2 and 3 (Black/Red wire). (Scheme 23) See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If voltage is 10-14 volts, go to next step. If voltage is less than 10 volts, check power and ground circuit to ECM. If ECM power and ground circuit are okay, repair open or short circuit to ground in Black/Red wire between ECM and fuel pump relay. After repair, retest system for normal operation.
3. Perform fuel pump relay component test. See «RELAYS»(ref-158706-S18366789222003101500000) under RELAYS & SOLENOIDS in SYSTEM & COMPONENT TESTING article. If fuel pump relay is okay, go to next step. If fuel pump relay is faulty, replace relay. After repair, retest system for normal operation.
4. Turn ignition to LOCK position. Disconnect engine harness connector G01 to instrument panel harness connector C42, located under right side of dash panel. Check for proper connection at Gray/Blue wire terminals, between connectors G01 and C42. Connect fuel pump relay to relay/fuse box. Connect DVOM between ground and ECM harness connector G04 terminal 12(Gray/Blue wire). (Scheme 24) See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Measure voltage 3 seconds after ignition switch is turned to ON position. if voltage is 10-14 volts, go to next step. If voltage is 10 volts or less, repair open circuit or short to ground in Gray/Blue wire between ECM and fuel pump relay. After repair, retest system for normal operation.
5. Within 3 seconds of turning ignition switch to ON position. Measure voltage between ground and ECM harness connector G04 terminals 12 (Gray/Blue wire). (Scheme 24) See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If voltage is 0-1 volt, go to next step. If voltage is more than one volt, substitute ECM with known good module. See «ENGINE CONTROL MODULE»(ref-157824-S39119365112003082700000) under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article.After repair, retest system for normal operation.
6. Turn ignition switch to LOCK position. Detach fuel tank. See «FUEL TANK & FUEL PUMP»(ref-157824-S39073941992003082700000) under FUEL SYSTEM in REMOVAL & INSTALLATION article. Disconnect fuel pump 4-pin harness connector L50, located on fuel tank. Measure resistance between ground and fuel pump harness connector L50 terminal No. 3 (Pink wire). (Scheme 25) See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If resistance is infinity, go to next step. If any resistance is found, repair short to ground in Pink wire between fuel pump and fuel pump relay. After repair, retest system for normal operation.
7. Ensure ignition switch is in LOCK position. Connect a fused jumper wire between ground and ECM harness connector G04 terminals No. 12 (Gray/Blue wire). (Scheme 24) Turn ignition switch to ON position. Measure voltage between ground and fuel pump connector L50 terminal No. 3 (Pink wire). (Scheme 25) See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If voltage is 10-14 volts, go to next step. If voltage is less than 10 volts, repair open circuit in Pink wire between fuel pump and fuel pump relay. After repair, retest system for normal operation.
8. Turn ignition switch to LOCK position. Check for continuity between fuel pump harness connector L50 terminals No. 4 (Black wire). (Scheme 25) See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Turn ignition switch to LOCK position. If continuity is found, replace faulty fuel pump. See «FUEL TANK & FUEL PUMP»(ref-157824-S39073941992003082700000) under FUEL SYSTEM in REMOVAL & INSTALLATION article. If continuity is not found, repair open circuit in Black wire, between fuel pump relay and ground point 15, 17 or 20. After repair, retest system for normal operation.

Scheme 22

Scheme 23

Scheme 24

Note. Perform all voltage and resistance tests using a Digital Volt-Ohm Meter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens.

1. Using a mechanic's stethoscope at gas tank, check for fuel pump operation sound when ignition switch is turned ON. If fuel pump operation sound is heard for 3 second and stop, circuit is in good condition. If fuel pump operation sound is not heard, go to next step.
2. Turn ignition switch to LOCK position. Disconnect fuel pump relay from relay/fuse box, located on left side, under dash panel. (Scheme 7)and (Scheme 8). Connect a fused jumper wire at relay/fuse box, between fuel pump relay connector E07 terminals No. 5 and 6 (Grand Vitara and XL-7), and fuel pump relay connector E07 terminals No. 7 and 8 (Vitara). (Scheme 26)and (Scheme 27). If fuel pump operation noise is not heard when ignition switch is turned ON, go to next step. If fuel pump operation sound is heard when ignition switch is turned ON, go to step 4.
3. Turn ignition switch to LOCK position. Check for open circuit in Pink/Black wire between fuel pump and fuel pump relay, in Blue/Black wire between fuel pump relay and main relay, and in Black wire between fuel pump and ground point No. 12. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If open circuit if found, repair as necessary. If open circuit is not found, perform fuel pump component test. See «FUEL PUMP»(ref-158706-S17609909752003101500000) under FUEL SYSTEM in SYSTEM & COMPONENT TESTING article. After repair, retest system for normal operation.
4. Perform fuel pump relay component test. See «RELAYS»(ref-158706-S18366789222003101500000) under RELAYS & SOLENOIDS in SYSTEM & COMPONENT TESTING article. If fuel pump relay is faulty, replace as necessary. If fuel pump relay is okay, repair open circuit in Black/White wire between fuel pump relay and relay/fuse box, or in White/Green wire between fuel pump relay and ECM. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. After repair, retest system for normal operation.

Scheme 25

Scheme 26

1. Check fuel pressure as ignition switch is cycled on and off. See appropriate fuel pressure test under «FUEL PRESSURE»(ref-157312-S23533648132003080800000) . 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. After testing fuel pressure and fuel pump stops, fuel system should hold 29 psi (2.0 kg/cm 2 ) of pressure or greater for one minute. If fuel pressure holds as specified, go to next step. If fuel pressure does not holds as specified, go to step 4 .
3. Start engine and allow it to reach normal operating temperature. Check fuel pressure with engine running at idle speed. Fuel pressure should be 31.3-36.9 psi (2.2-2.6 kg/cm 2 ). If fuel pressure is as specified, system is operating properly. If fuel pressure is not as specified, check for clogged vacuum hose passage to fuel pressure regulator or faulty fuel pressure regulator. Repair or replace as necessary. After repair, retest system for normal operation.
4. Check for fuel leaks at fuel feed hose, pipe or connections. If no leaks are present, go to step 10 . If leaks are present, repair or replace as necessary. After repair, retest system for normal operation.
5. If fuel pressure is greater than 38.4-44.0 psi (2.7-3.1 kg/cm 2 ), go to next step. If fuel pressure is lower than 38.4-44.0 psi (2.7-3.1 kg/cm 2 ), 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 switch to ON position. If fuel pressure is 38.4-44.0 psi (2.7-3.1 kg/cm 2 ), repair or replace restriction in fuel return hose. If fuel pressure is not as specified, replace fuel pressure regulator. See «FUEL PRESSURE REGULATOR»(ref-157824-S28119371682003082700000) under FUEL SYSTEM in REMOVAL & INSTALLATION article. After repair, retest system for normal operation.
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. Pinch fuel return hose. Turn ignition switch to ON position. If fuel pressure does not increases, go to «B-3: FUEL PUMP CIRCUIT INSPECTION»(ref-157312-S14054230572003080800000) . If fuel pressure increases, replace fuel pressure regulator. See «FUEL PRESSURE REGULATOR»(ref-157824-S28119371682003082700000) under FUEL SYSTEM in REMOVAL & INSTALLATION article. After repair, retest system for normal operation.
9. Pinch fuel return hose. Turn ignition switch to ON position. If fuel pressure is 63.9 psi (4.5 kg/cm 2 ) or greater, replace fuel pressure regulator. See «FUEL PRESSURE REGULATOR»(ref-157824-S28119371682003082700000) under FUEL SYSTEM in REMOVAL & INSTALLATION article. If fuel pressure is lower than 63.9 psi (4.5 kg/cm 2 ), check for clogged fuel filter, restricted fuel feed hose, faulty fuel pump or fuel leakage at hose connection in fuel tank. Repair or replace as necessary. After repair, retest system for normal operation.
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. See «FUEL PRESSURE REGULATOR»(ref-157824-S28119371682003082700000) under FUEL SYSTEM in REMOVAL & INSTALLATION article. 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 or replace as necessary. After repair, retest system for normal operation.

Note. Before performing fuel pressure inspection procedure, ensure battery is in good condition and fully charged.

1. Using a mechanic's stethoscope at gas tank, check for fuel pump operation sound when ignition switch is turned ON. If fuel pump operation sound is heard for 3 second and stops, go to next step. If fuel pump operation sound is not heard, go to «B-3: FUEL PUMP CIRCUIT INSPECTION»(ref-157312-S14054230572003080800000) .
2. Check fuel pressure, see appropriate fuel pressure test under «FUEL PRESSURE»(ref-157312-S23533648132003080800000) . 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 38.4-44.0 psi (2.7-3.1 kg/cm 2 ), go to step 6 .
3. After testing fuel pressure and fuel pump stops, fuel system should hold 29 psi (2.0 kg/cm 2 ) of pressure or greater for one minute. If fuel pressure holds as specified, go to next step. If fuel pressure does not holds as specified, go to step 5 .
4. Start engine and allow it to reach normal operating temperature. Check fuel pressure with engine running at idle speed. Fuel pressure should be 30.4-44.9 psi (2.1-3.1 kg/cm 2 ). If fuel pressure is as specified, system is operating properly. If fuel pressure is not as specified, check for clogged vacuum hose passage to fuel pressure regulator or faulty fuel pressure regulator. Repair or replace as necessary. After repair, retest system for normal operation.
5. Check for fuel leaks at fuel feed hose, pipe or connections. If leaks are present, repair or replace as necessary. If no leaks are present, check fuel leakage from fuel injectors, fuel pressure regulator and/or fuel pump, repair or replace as necessary. After repair, retest system for normal operation.
6. If fuel pressure is greater than 38.4-44.0 psi (2.7-3.1 kg/cm 2 ), go to next step. If fuel pressure is lower than 38.4-44.0 psi (2.7-3.1 kg/cm 2 ), go to step 8 .
7. Disconnect fuel return hose from fuel pressure regulator. Connect a separate hose to pressure regulator and insert hose end into a container. Turn ignition switch to ON position. If fuel pressure is 38.4-44.0 psi (2.7-3.1 kg/cm 2 ), repair or replace restriction in fuel return hose. If fuel pressure is not as specified, replace fuel pressure regulator. See «FUEL PRESSURE REGULATOR»(ref-157824-S28119371682003082700000) under FUEL SYSTEM in REMOVAL & INSTALLATION article. After repair, retest system for normal operation.
8. Pinch fuel return hose. Turn ignition switch to ON position. If fuel pressure is 63.9 psi (4.5 kg/cm 2 ) or greater, replace fuel pressure regulator. See «FUEL PRESSURE REGULATOR»(ref-157824-S28119371682003082700000) under FUEL SYSTEM in REMOVAL & INSTALLATION article. If fuel pressure is lower than 63.9 psi (4.5 kg/cm 2 ), check for clogged fuel filter, restricted fuel feed hose, faulty fuel pump or fuel leakage at hose connection in fuel tank. Repair or replace as necessary. After repair, retest system for normal operation.

Vitara & XL-7

Note. Before performing fuel pressure inspection procedure, ensure battery is in good condition and fully charged.

1. Check fuel pressure, see appropriate fuel pressure test under «FUEL PRESSURE»(ref-157312-S23533648132003080800000) . If fuel pressure is 35.6-42.7 psi (2.5-3.0 kg/cm 2 ), go to next step. If fuel pressure is not 35.6-42.7 psi (2.5-3.0 kg/cm 2 ), go to step 5 .
2. After testing fuel pressure and fuel pump stops, fuel system should hold 25.6 psi (1.8 kg/cm 2 ) of pressure or greater for one minute. If fuel pressure holds as specified, go to next step. If fuel pressure does not holds as specified, go to step 4 .
3. Start engine and allow it to reach normal operating temperature. Check fuel pressure with engine running at idle speed. Fuel pressure should be 29.8-37.0 psi (2.1-2.6 kg/cm 2 ). If fuel pressure is as specified, system is operating properly. If fuel pressure is not as specified, check for clogged vacuum hose passage for fuel pressure regulator or faulty fuel pressure regulator. Repair or replace as necessary. After repair, retest system for normal operation.
4. Check for fuel leaks from fuel feed hose, pipe or connections. If no leaks are present, go to step 10 . If leaks are present, repair or replace as necessary. After repair, retest system for normal operation.
5. If fuel pressure is greater than 35.6-42.7 psi (2.5-3.0 kg/cm 2 ), go to next step. If fuel pressure is lower than 35.6-42.7 psi (2.5-3.0 kg/cm 2 ), 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 switch to ON position. If fuel pressure is 35.6-42.7 psi (2.5-3.0 kg/cm 2 ), repair or replace restriction in fuel return hose. If fuel pressure is not 35.6-42.7 psi (2.5-3.0 kg/cm 2 ), replace fuel pressure regulator. See «FUEL PRESSURE REGULATOR»(ref-157824-S28119371682003082700000) under FUEL SYSTEM in REMOVAL & INSTALLATION article. After repair, retest system for normal operation.
7. If no fuel pressure was present on step 1 , go to next step. If fuel pressure is lower than 35.6-42.7 psi (2.5-3.0 kg/cm 2 ) was found on step 1 , go to step 9
8. Pinch fuel return hose. Turn ignition switch to ON position. If fuel pressure is present, replace fuel pressure regulator. See «FUEL PRESSURE REGULATOR»(ref-157824-S28119371682003082700000) under FUEL SYSTEM in REMOVAL & INSTALLATION article. If fuel pressure present is to low, check fuel pump and/or fuel pump circuit, see «B-3: FUEL PUMP CIRCUIT INSPECTION»(ref-157312-S14054230572003080800000) . After repair, retest system for normal operation.
9. Pinch fuel return hose. Turn ignition switch to ON position. If fuel pressure is 63.9 psi (4.5 kg/cm 2 ) or greater, replace fuel pressure regulator. See «FUEL PRESSURE REGULATOR»(ref-157824-S28119371682003082700000) under FUEL SYSTEM in REMOVAL & INSTALLATION article. If fuel pressure is lower than 63.9 psi (4.5 kg/cm 2 ), check for clogged fuel filter, restricted fuel feed hose, faulty fuel pump or fuel leakage at hose connection in fuel tank. Repair or replace as necessary. After repair, retest system for normal operation.
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. See «FUEL PRESSURE REGULATOR»(ref-157824-S28119371682003082700000) under FUEL SYSTEM in REMOVAL & INSTALLATION article. 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 or replace as necessary. After repair, retest system for normal operation.

1. Perform engine system check. See «B-1: ENGINE SYSTEM CHECK»(ref-157312-S04301383462003091500000) under CIRCUIT TESTS.
2. Remove spark plugs. See «SPARK PLUGS & IGNITION COIL ASSEMBLY»(ref-157824-S40644651432003082700000) under IGNITION SYSTEM in REMOVAL & INSTALLATION article. Check spark plugs for proper application, electrode wear, carbon deposits or insulator damage. If spark plugs are faulty, replace as necessary. If spark plugs are okay, perform spark test. See «SPARK TEST»(ref-157312-S11017747392003080800000) under IGNITION CHECKS. If spark is faulty, go to next step. If spark is okay, go to step 8 .
3. If no DTCs were retrieved during engine system check, go to next step. If any DTCs were retrieved, perform system test. See appropriate SYSTEM TESTS in appropriate SELF-DIAGNOSTICS article.
4. Check for proper connection between each ignition coil assembly and spark plug, also between each ignition coil assembly and harness connector and terminals. If connections are okay, go to next step. If connections are faulty, repair as necessary and reconnect securely. After repair, retest system for normal operation.
5. Check ignition coil power, ground and trigger circuit for open or short. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If all circuits are okay, go to next step. If any circuit is faulty, repair as necessary. After repair, retest system for normal operation.
6. Substitute a suspect ignition coil assembly with known-good ignition coil assembly and perform spark test. See «SPARK TEST»(ref-157312-S11017747392003080800000) under IGNITION CHECKS. If test result is faulty, go to next step. If test result is okay, replace ignition coil assembly.
7. Check Camshaft Position (CMP) sensor circuits for open or short referring to DTC P0340: CAMSHAFT POSITION SENSOR - CIRCUIT MALFUNCTION under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article. If test results are okay, substitute ECM with known-good module and repeat test in step 2 .If test results are faulty, repair as necessary. After repair, repeat test in step 2 .
8. Check ignition timing and timing advance. See «IGNITION TIMING»(ref-157310-S28143868672003080800000) in ON-VEHICLE ADJUSTMENTS article. If ignition timing and timing advance are okay, testing is complete. If ignition timing and timing advance are faulty, check timing belt installation and ECM input signals related to ignition system, repair as necessary and adjust ignition timing. After repair, retest system for normal operation.

1. Check engine idle speed and Idle Air Control (IAC) duty cycle. See «IDLE SPEED»(ref-157310-S08889276462003081200000) under IDLE SPEED & MIXTURE 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. Start engine and allow it to idle until reaches normal operating temperature. Turn headlights, heater blower and rear defogger ON. If idle speed stays within specifications, this part of system is operating properly, go to next step. If idle speed drops below specification, go to step 6 .
3. With engine running at idle speed, turn steering wheel right and left as far as it stops (only vehicles equipped with power steering system). If idle speed stays within specifications, this part of system is operating properly, go to next step. If idle speed do not stays within specifications, check power steering pressure switchsignal circuit, see POWER STEERING PRESSURE SWITCH under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING article. If check result is okay, go to step 6 .
4. Turn ignition switch to LOCK position. Check for clogged air intake system, also check fast idle plunger length. See «COLD (FAST) IDLE»(ref-157310-S38805746452003081200000) under IDLE SPEED & MIXTURE in ON-VEHICLE ADJUSTMENTS article. If check results are okay, go to next step. If check results are faulty, repair as necessary. After repair, retest system for normal operation.
5. Check IAC valve operation referring to DTC P0505, P0506 & P0507: IDLE CONTROL SYSTEM MALFUNCTION/IDLE CONTROL SYSTEM - RPM LOWER THAN EXPECTED & IDLE CONTROL SYSTEM - RPM HIGHER THAN EXPECTED under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article. If test results are faulty, go to next step. If test results are okay, go to step 7 .
6. Perform IAC valve component test. See IDLE AIR CONTROL VALVE under IDLE CONTROL SYSTEM in SYSTEM & COMPONENT TESTING article. If check results are faulty, repair or replace IAC valve. See «IDLE AIR CONTROL VALVE»(ref-157824-S25305030552003090900000) under in REMOVAL & INSTALLATION article. If check results are okay, check for IAC valve circuits for open or short. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If IAC valve circuits are faulty, repair as necessary. If IAC valve circuits are okay, substitute ECM with known-good module and retest system for normal operation.
7. Check A/C input signal to ECM. See «A/C SIGNALS CIRCUIT CHECK»(ref-158706-S16779344502003101500000) under MISCELLANEOUS CONTROLS in SYSTEM & COMPONENT TESTING article. If input signal is okay, go to next step. If input signal is faulty, repair as necessary. After repair, retest system for normal operation.
8. Check for malfunction at following systems and system components: EGR valve malfunction. Engine coolant temperature sensor malfunction. Engine mechanical malfunction. EVAP system malfunction. High accessory engine load. Throttle position sensor malfunction. PCV system malfunction. If no malfunction is found, go to next step. If malfunction is found, repair system or replace component as necessary. After repair, retest system for normal operation.
9. Check engine idle speed and Idle Air Control (IAC) duty cycle. See appropriate «IDLE SPEED»(ref-157310-S08889276462003081200000) under IDLE SPEED & MIXTURE in ON-VEHICLE ADJUSTMENTS article. If idle speed and duty cycle are 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 module and retest system for normal operation.

1. Check engine idle speed and Idle Air Control (IAC) duty cycle. See «IDLE SPEED»(ref-157310-S08889276462003081200000) under IDLE SPEED & MIXTURE 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 3.
2. With engine operating at normal temperature and running at idle speed, turn headlights, heater blower and rear defogger ON. If idle speed stays within specifications, this part of system is operating properly. If idle speed drops below specification, go to next step.
3. Perform IAC valve component test. See «IDLE AIR CONTROL VALVE»(ref-158706-S30889331512003101500000) under IDLE CONTROL SYSTEM in SYSTEM & COMPONENT TESTING article. If check results are okay, go to next step. If check results are faulty, check all IAC valve circuits for open or short. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If IAC valve circuits are faulty, repair as necessary. If IAC valve circuits are okay, substitute ECM with known-good module and retest system for normal operation.
4. If idle speed was not as specified in step 1, go to next step. If idle speed was as specified in step 1, check for malfunction at following systems and system components: Air induction system (clogged). Engine coolant temperature sensor malfunction. Engine mechanical malfunction. EGR valve malfunction. EVAP system malfunction. High accessory engine load (A/C, P/S & Lighting). Manifold absolute pressure sensor malfunction. PCV system malfunction. Throttle position sensor malfunction. Transmission range switch signal. Vacuum leaks. If no malfunction is found, go to next step. If malfunction is found, repair system or replace component as necessary. After repair, retest system for normal operation.
5. If idle speed was higher than specified in step 1, go to next step. If idle speed was lower than specified in step 1, go to step 8.
6. Turn ignition switch to LOCK position. Disconnect appropriate ECM harness connector E61. ECM is located under instrument panel, behind glove box. (Scheme 17) Turn ignition switch to ON position. Using DVOM, check A/C (input) signal circuit by measuring voltage between ground and appropriate ECM connector. See «CHECKING A/C SWITCH SIGNAL CIRCUIT»(ref-157312-S01004411072003091200000). see scheme 28 See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Voltage should be 10-14 volts with A/C and blower switch OFF. And 0-1.5 volts with A/C and blower switch ON. If A/C (input) signal circuit is okay, go to next step. If A/C (input) signal circuit is faulty, repair open or short circuit in appropriate wire between A/C control module and ECM. After repair, retest system for normal operation. CHECKING A/C SWITCH SIGNAL CIRCUIT Application ECM Harness Connector/Terminal (Wire Color) Grand Vitara E61/28 (Green/Black) Vitara E61/17 (Yellow/Black wire) XL-7 E61/17 (Green/Black)
7. If IAC valve duty was less than about 2% in step 1, check air induction system, PCV valve and EVAP canister purge control system for proper operation, repair as necessary. If IAC valve duty was more than about 2% in step 1, check TP sensor (close throttle position) and ECT sensor for performance. If sensors are faulty, replace as necessary. If sensors are okay, substitute ECM with known-good module and retest system for normal operation.
8. Check transmission range signal, referring to DTC P0705 & P0707: TRANSMISSION RANGE SENSOR CIRCUIT MALFUNCTION (P, R, N, D & L INPUT)/TRANSMISSION RANGE SENSOR CIRCUIT LOW INPUT under appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS. If test results are okay, go to next step. If test results are faulty, repair as necessary. After repair, retest system for normal operation.
9. If IAC valve duty was more than about 30% in step 1, check for malfunction at following systems and systems components: Air induction system. EGR valve malfunction (leakage from valve seat). High accessory engine load. If IAC valve duty was less than about 30% in step 1, substitute ECM with known-good module and retest system for normal operation.

Scheme 27

SUMMARY

If no faults were found while performing BASIC DIAGNOSTIC PROCEDURES, proceed to appropriate SELF-DIAGNOSTICS article. If no hard codes are found in self-diagnostics, proceed to TROUBLE SHOOTING - NO-CODES article for diagnosis by symptom (i.e., rough idle, no start, etc.) or intermittent diagnostic procedures.