Engine Control System Self-Diagnostics - 4-CYLINDER: Diagnosis Toyota 4Runner III

DIAGNOSTIC TROUBLE CODE DEFINITIONS

DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION

DIAGNOSTIC TESTS

Note. Before performing any diagnostic test, refer to SELF-DIAGNOSTICS - INTRODUCTION article for diagnostic system functions and system diagnostic procedures. For component location, see appropriate illustration in THEORY & OPERATION article. To identify circuits and wire colors referenced in testing, see appropriate wiring diagrams in WIRING DIAGRAMS article.

Circuit Description

MAF meter uses a platinum hot wire maintained at a constant temperature. Airflow past sensor affects temperature and current flow through MAF meter. DTC is set when ECM detects an open or short in MAF meter circuit for more than 3 seconds with engine speed at 4000 RPM or less. ECM will operate in fail-safe mode if DTC P0100 is set. Possible causes are

1. MAF meter circuit is open or shorted.
2. Defective MAF meter.
3. Defective ECM.

Diagnostic Aids

After confirming DTC P0100, use scan tool to access CURRENT DATA to confirm mass airflow ratio. If ratio is 0.0 gm/sec., VG circuit may be open or shorted, or power source circuit may be open. If ratio is 202.2 gm/sec. or more, E3 circuit may be open. Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

Diagnosis & Repair

1. Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 64) Start and warm engine to normal operating temperature. Using scan tool, monitor MAF flow rate. If scan tool reading is 0.0 gm/sec., go to next step. If scan tool reading is 202.2 gm/sec. or more, go to step 5.
2. Turn ignition off. Disconnect MAF meter harness connector. Turn ignition on. Measure voltage between ground and terminal No. 3 (White/Blue wire) at MAF meter harness connector. (Scheme 65) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, repair for open in White/Blue wire between EFI main relay and MAF meter. See appropriate wiring diagram in WIRING DIAGRAMS article.
3. Turn ignition off. Connect MAF meter harness connector. Access ECM behind glove box. Ensure shift lever is in Neutral or Park. Ensure A/C switch is off. Start engine and let idle. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 2 (Black/Red wire) at ECM harness connector E6. (Scheme 66) If voltage is not 1.1-1.5 volts, go to next step. If voltage is 1.1-1.5 volts, replace ECM.
4. Check for open or short in Black/Red wire between MAF meter and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace MAF meter.
5. Turn ignition off. Access ECM behind glove box. Using DVOM, backprobe ECM harness connector and measure resistance between ground and terminal No. 7 (Red/White wire) at ECM harness connector E7. (Scheme 66) If resistance is one ohms or less, go to next step. If resistance is greater than one ohm, replace ECM.
6. Check for open in Red/White wire between MAF meter and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace MAF meter.

Scheme 64

Scheme 65

Scheme 66

MAF meter uses a platinum hot wire maintained at a constant temperature. Airflow past sensor affects temperature and current flow through MAF meter. DTC is set when ECM detects either throttle valve is fully closed and MAF meter output is more than 2.2 volts for more than 10 seconds with engine speed of 900 RPM or less, or VTA circuit signal is .75 volt or more and MAF meter output is less than one volt for more than 10 seconds with engine speed of 1850 RPM or more. ECM will operate in fail-safe mode if DTC P0101 is set. Possible cause is

1. Defective MAF meter.

After confirming DTC P0101, use scan tool to access CURRENT DATA to confirm mass airflow ratio. If ratio is 0.0 gm/sec., VG circuit may be open or shorted, or power source circuit may be open. If ratio is 202.2 gm/sec. or more, EVG circuit may be open. Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

If only DTC P0101 is displayed, replace MAF meter. If other DTCs are displayed, diagnose and repair those DTCs first and retest.

1. Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 64) Turn ignition on. Using scan tool, monitor IAT sensor temperature. If temperature displayed on scan tool is same as outside temperature, problem is intermittent. Check component and ECM connections. If temperature displayed on scan tool is -40°F (-40°C), go to next step. If temperature displayed on scan tool is 284°F (140°C) or more, go to step 4.
2. Turn ignition off. Disconnect MAF meter harness connector. Using a jumper wire, connect MAF meter harness connector terminals No. 1 (Blue/Black wire) and No. 2 (Yellow/Green wire). (Scheme 65) Turn ignition on. Using scan tool, monitor IAT sensor temperature. If temperature displayed on scan tool is 284°F (140°C) or more, replace MAF meter. If temperature displayed on scan tool is less than 284°F (140°C), go to next step.
3. Turn ignition off. Remove jumper wire. Access ECM behind glove box. Using a jumper wire, backprobe between terminals No. 9 (Blue/Black wire) and No. 3 (Yellow/Green wire) at ECM harness connector E6. (Scheme 66) If temperature displayed on scan tool is 284°F (140°C) or more, repair open in Yellow/Green wire and/or Blue/Black wire between MAF meter and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If temperature displayed on scan tool is less than 284°F (140°C), replace ECM.
4. Turn ignition off. Disconnect MAF meter harness connector. Turn ignition on. If temperature displayed on scan tool is -40°F (-40°C), replace MAF meter. If temperature displayed on scan tool is not -40°F (-40°C), go to next step.
5. Turn ignition off. Access ECM behind glove box. Disconnect ECM harness connector E6. (Scheme 66) Turn ignition on. If temperature displayed on scan tool is -40°F (-40°C), repair short in Yellow/Green wire between MAF meter and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If temperature displayed on scan tool is not -40°F (-40°C), replace ECM.

1. Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 64) Turn ignition on. Using scan tool, monitor ECT sensor temperature. If temperature displayed on scan tool is same as actual coolant temperature, problem is intermittent. Check component and ECM connections. If temperature displayed on scan tool is -40°F (-40°C), go to next step. If temperature displayed on scan tool is 284°F (140°C) or more, go to step 4.
2. Turn ignition off. Disconnect ECT sensor harness connector (2-pin harness connector with Green/Red wire and Blue/Black wire). Using a jumper wire, connect ECT sensor harness connector terminals. Turn ignition on. Using scan tool, monitor ECT sensor temperature. If temperature displayed on scan tool is less than 284°F (140°C), go to next step. If temperature displayed on scan tool is 284°F (140°C) or more, replace ECT sensor.
3. Turn ignition off. Remove jumper wire. Access ECM behind glove box. Using a jumper wire, backprobe between terminals No. 9 (Blue/Black wire) and No. 4 (Green/Red wire) at ECM harness connector E6. (Scheme 66) If temperature displayed on scan tool is 284°F (140°C) or more, repair open in Green/Red wire and/or Blue/Black wire between ECT sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If temperature displayed on scan tool is less than 284°F (140°C), replace ECM.
4. Turn ignition off. Disconnect ECT sensor harness connector (2-pin harness connector with Green/Red wire and Blue/Black wire). Turn ignition on. If temperature displayed on scan tool is -40°F (-40°C), replace ECT sensor. If temperature displayed on scan tool is not -40°F (-40°C), go to next step.
5. Turn ignition off. Access ECM behind glove box. Disconnect ECM harness connector E6. (Scheme 66) Turn ignition on. If temperature displayed on scan tool is -40°F (-40°C), repair short in Green/Red wire between ECT sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If temperature displayed on scan tool is not -40°F (-40°C), replace ECM.

1. If any other DTCs are displayed, diagnose and repair those DTCs first and retest. If only DTC P0116 is displayed, go to next step.
2. Remove and inspect cooling system thermostat. If problem exists, replace thermostat as necessary and retest. If problem does not exist, replace ECT sensor.

1. Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 64) Turn ignition on. Using scan tool, monitor throttle valve opening percentage. Opening percentage should be approximately 10 percent with fully closed throttle and should be approximately 75 percent with throttle fully open (WOT). If percentages are as specified, problem is intermittent. Check component and ECM connections. If percentages are not as specified, go to next step.
2. Turn ignition off. Disconnect TP sensor harness connector. Turn ignition on. Using DVOM, measure voltage between ground and terminal No. 2 (Green/Yellow wire) at TP sensor harness connector. If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, go to step 5.
3. Check TP sensor. See ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, replace TP sensor. If problem does not exist, go to next step.
4. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 9 (Blue/Black wire) and No. 10 (Yellow wire) at ECM harness connector E6. (Scheme 66) Voltage should be.3-1.0 volt with throttle fully closed, and 3.2-4.9 volts with throttle fully open (WOT). If voltages are as specified, replace ECM. If voltages are not as specified, repair open or short in wiring between TP sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article.
5. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe and measure voltage between terminals No. 1 (Green/Yellow wire) and No. 9 (Blue/Black wire) at ECM harness connector E6. (Scheme 66) If voltage is 4.5-5.5 volts, repair open in Green/Yellow wire between TP sensor and ECM. If voltage is not 4.5-5.5 volts, replace ECM.

TP sensor is located on throttle body and has a variable resistor integral to TP sensor. TP sensor monitors throttle opening. ECM determines vehicle driving condition and adjusts air/fuel mixture accordingly. DTC is set when ECM detects TP sensor output voltage is out of range during vehicle operation. Possible cause is

1. Defective Throttle Position (TP) sensor.

After confirming DTC P0120, use scan tool to access CURRENT DATA to confirm throttle valve opening percentage with throttle open and closed. If percentage displayed on scan tool is always zero percent, VCC circuit may be open, or VTA circuit may be open or shorted. If percentage displayed on scan tool is always 100 percent, E2 circuit may be open. Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

If any other DTCs are displayed, diagnose and repair those DTCs first and retest. If only DTC P0121 is displayed, replace TP sensor.

1. If any other DTCs are displayed, diagnose and repair those DTCs first and retest. If only DTC P0125 is displayed, go to next step.
2. Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 64) Start and warm engine to normal operating temperature. Using scan tool, monitor heated oxygen sensor No. 1 output voltage. Snap accelerate engine to about 4000 RPM 3 times. Heated oxygen sensor No. 1 should indicate a rich signal (.45 volt or more) at least once. If a rich signal is indicated for heated oxygen sensor No. 1 at least once, go to step 10. If either heated oxygen sensor No. 1 does not display a rich signal at least once, go to next step.
3. Check for open or short in wiring between heated oxygen sensor No. 1 and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem does not exist, go to next step. If problem exists, repair wiring as necessary.
4. Using scan tool, check if a misfire has occurred by monitoring DTCs and DATA LIST. If a misfire has occurred, perform «DTC P0300: RANDOM MISFIRE DETECTED»(ref-91235-S11657763832001030600000). If misfire has not occurred, go to next step.
5. Ensure oil dipstick, oil filler cap, PCV system and all other air induction system components are intact and operating properly. If problem exists, repair as necessary. If problem does not exist, go to next step.
6. Check EGR system components. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, repair as necessary. If problem does not exist, go to next step.
7. Check fuel pressure. See FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If fuel pressure is not within specification, repair as necessary. If fuel pressure is within specification, go to next step.
8. Check fuel injectors. See FUEL SYSTEM in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, repair as necessary. If problem does not exist, go to next step.
9. Check exhaust system for leaks. If problem exists, repair as necessary. If problem does not exist, replace defective heated oxygen sensor No. 1.
10. Perform test drive confirmation, then go to next step. See «TEST DRIVE CONFIRMATION»(ref-91235-S33797824912001030600000) under DTC P0130: HEATED OXYGEN SENSOR NO. 1 CIRCUIT.
11. Clear and recheck for DTCs. If DTC P0125 is displayed again, replace ECM. If DTC P0125 is not displayed again, go to next step.
12. Vehicle either ran out of fuel or problem is intermittent. Check component and ECM connections.

Test Drive Confirmation

Note. If conditions in test drive confirmation procedure are not strictly followed, detection of malfunction will not be possible.

1. If using OBD-II scan tool, go to step 3. If using Toyota hand-held tester, connect hand-held tester to Data Link Connector (DLC) No. 3. (Scheme 64) Switch tester to CHECK mode and go to next step.
2. Start and warm engine to normal operating temperature with all accessories off. Drive vehicle at 31-40 MPH for 1-3 minutes. Stop vehicle and allow to idle for one minute. Repeat driving and idle part of test 3 times. If malfunction exists, MIL will illuminate.
3. Start and warm engine to normal operating temperature with all accessories off. Drive vehicle at 31-40 MPH for 1-3 minutes. Stop vehicle and allow to idle for one minute. Turn ignition off. Repeat driving and idle part of test. If malfunction exists, MIL will illuminate.

1. If other DTCs are displayed, diagnose and repair those DTCs first and retest system. If only DTC P0130 is displayed, go to next step.
2. Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 64) Start engine and increase engine speed to 2500 RPM for approximately 90 seconds. Let engine idle. Using scan tool, monitor heated oxygen senor No. 1 output voltage. Voltage should alternate repeatedly between less than.35 volt and more than.55 volt. If voltage is as specified, go to step 8. If voltage is not as specified, go to next step.
3. Check for open or short in wiring between ECM and heated oxygen sensor No. 1. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
4. Ensure oil dipstick, oil filler cap, PCV system and all other air induction system components are intact and operating properly. If problem exists, repair as necessary. If problem does not exist, go to next step.
5. Check EGR system components. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, repair as necessary. If problem does not exist, go to next step.
6. Check fuel pressure. See FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If fuel pressure is not within specification, repair as necessary. If fuel pressure is within specification, go to next step.
7. Check fuel injectors. See FUEL SYSTEM in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, repair as necessary. If problem does not exist, replace appropriate heated oxygen sensor No. 1.
8. Perform test drive confirmation, then go to next step. See «TEST DRIVE CONFIRMATION»(ref-91235-S33797824912001030600000).
9. Clear and recheck for DTCs. If DTC P0130 is displayed again, replace ECM. If DTC P0130 is not displayed again, problem is intermittent. Check component and ECM connections.

1. If other DTCs are displayed, diagnose and repair those DTCs first and retest system. If only DTC P0133 is displayed, go to next step.
2. Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 64) Start engine and increase engine speed to 2500 RPM for approximately 90 seconds. Let engine idle. Using scan tool, monitor heated oxygen sensor No. 1 output voltage. Voltage should alternate repeatedly between less than.35 volt and more than.55 volt. If voltage is as specified, go to step 8. If voltage is not as specified, go to next step.
3. Check for open or short in wiring between ECM and heated oxygen sensor No. 1. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
4. Ensure oil dipstick, oil filler cap, PCV system and all other air induction system components are intact and operating properly. If problem exists, repair as necessary. If problem does not exist, go to next step.
5. Check EGR system components. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, repair as necessary. If problem does not exist, go to next step.
6. Check fuel pressure. See FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If fuel pressure is not within specification, repair as necessary. If fuel pressure is within specification, go to next step.
7. Check fuel injectors. See FUEL SYSTEM in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, repair as necessary. If problem does not exist, replace appropriate heated oxygen sensor No. 1.
8. Perform test drive confirmation, then go to next step. See «TEST DRIVE CONFIRMATION»(ref-91235-S33797824912001030600000) under DTC P0130: HEATED OXYGEN SENSOR NO. 1 CIRCUIT.
9. Clear and recheck for DTCs. If DTC P0133 is displayed again, replace ECM. If DTC P0133 is not displayed again, problem is intermittent. Check component and ECM connections.

1. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 2 (Pink wire) at ECM harness connector E5. (Scheme 66) Voltage should be 9-14 volts. If voltage is as specified, replace ECM. If voltage is not as specified, go to next step.
2. Disconnect heated oxygen sensor No. 1 harness connector. Measure resistance between terminals B+ (White/Blue wire) and HT (Pink wire) at heated oxygen sensor connector (component side). (Scheme 67) Resistance should be 11-16 ohms at 68°F (20°C) and 23-32 ohms at 1472° (800°C). If resistance is not as specified, replace heated oxygen sensor No. 1. If resistance is as specified, go to next step.
3. Repair wiring between ECM and heated oxygen sensor No. 1, or between heated oxygen sensor No. 1 and EFI main relay. See appropriate wiring diagram in WIRING DIAGRAMS article.

Scheme 67

1. If any other DTCs are displayed, diagnose and repair those DTCs first. If only DTC P0136 is displayed, go to next step.
2. Check for open or short in wiring between ECM and heated oxygen sensor No. 2. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
3. Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 64) Start and warm engine to normal operating temperature. Monitor heated oxygen sensor No. 2 output voltage. Snap accelerate engine to about 4000 RPM 3 times. Voltage should fluctuate from less than.4 volt to.5 volt or more. If voltage is as specified, problem is intermittent. Check component and ECM connections. If voltage is not as specified, replace heated oxygen sensor No. 2.

1. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 1 (Red/White wire) at ECM harness connector E5. (Scheme 66) Voltage should be 9-14 volts. If voltage is as specified, replace ECM. If voltage is not as specified, go to next step.
2. Disconnect heated oxygen sensor No. 2 harness connector. Measure resistance between terminals B+ (White/Blue wire) and HT (Red/White wire) at heated oxygen sensor connector (component side). (Scheme 68) Resistance should be 11-16 ohms at 68°F (20°C) and 23-32 ohms at 1472° (800°C). If resistance is not as specified, replace heated oxygen sensor No. 2. If resistance is as specified, go to next step.
3. Repair wiring between ECM and heated oxygen sensor No. 2, or between heated oxygen sensor No. 2 and EFI main relay. See appropriate wiring diagram in WIRING DIAGRAMS article.

Scheme 68

1. Ensure oil dipstick, oil filler cap, PCV system and all other air induction system components are intact and operating properly. If problem exists, repair as necessary. If problem does not exist, go to next step.
2. Check fuel injectors. See FUEL SYSTEM in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, repair as necessary. If problem does not exist, go to next step.
3. Check Mass Airflow (MAF) meter and Engine Coolant Temperature (ECT) sensor. See ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, replace appropriate sensor(s). If problem does not exist, go to next step.
4. Check spark and ignition system. See IGNITION CHECKS in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If problem exists, repair as necessary. If problem does not exist, go to next step.
5. Check fuel pressure. See FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If fuel pressure is not within specification, repair as necessary. If fuel pressure is within specification, go to next step.
6. Check exhaust system for leaks. If problem exists, repair as necessary. If problem does not exist, go to next step.
7. Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 64) Start engine and increase engine speed to 2500 RPM for approximately 90 seconds. Let engine idle. Using scan tool, monitor heated oxygen sensor No. 1 output voltage. Voltage should alternate repeatedly from less than.35 volt to more than.55 volt. If voltage is as specified, go to step 9. If voltage is not as specified, go to next step.
8. Check for open or short in wiring between ECM and heated oxygen sensor No. 1. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace heated oxygen sensor No. 1.
9. Perform test drive confirmation, then go to next step. See «TEST DRIVE CONFIRMATION»(ref-91235-S33797824912001030600000) under DTC P0130: HEATED OXYGEN SENSOR NO. 1 CIRCUIT.
10. Clear and recheck for DTCs. If DTCs P0171 and/or P0172 are displayed again, replace ECM. If neither DTC P0171 nor P0172 are displayed again, go to next step.
11. Vehicle either ran out of fuel or problem is intermittent. Check component and ECM connections.

ECM uses signals provided by crankshaft and camshaft position sensors. If engine speed rate has changed enough to equal a preset number, a misfire is detected and MIL is illuminated. If misfire rate is high enough, and driving conditions will cause catalytic converter damage or overheating, MIL blinks when a misfire is occurring. DTC is set when misfiring of random cylinders is detected during any particular 200 or 1000 revolutions. Possible causes are

1. Ignition system malfunction.
2. Defective fuel injector(s).
3. Improper fuel pressure.
4. Defective engine compression.
5. EGR system malfunction.
6. Improper valve clearance.
7. Improper valve timing.
8. Defective Mass Airflow (MAF) meter.
9. Defective Engine Coolant Temperature (ECT) sensor.
10. Open or short in wiring.
11. Poor contact at ECM or component.
12. Defective ECM.

When 2 or more codes for misfiring cylinder are recorded repeatedly but no random misfire code is recorded, it indicates misfires were detected and recorded at different times. If misfire cannot be reproduced, reason may be because of driving with lack of fuel, improper fuel, fouled spark plug, etc. Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 64) Record any DTCs and freeze frame data. Switch scan tool to CHECK mode (Toyota hand-held tester only). Drive vehicle several times with engine speed, load and its surrounding range shown with ENGINE SPD, CALC LOAD in freeze frame data or MISFIRE RPM and MISFIRE LOAD in scan tool data list.
2. Drive vehicle at specified engine speeds. See «DRIVING PATTERN»(ref-91235-S23052810042001030600000) table. Turn ignition off after symptom is simulated the first time, then repeat test drive again (OBD-II scan tool only). If a misfire is detected, a DTC will set and misfire will be indicated in freeze frame data. Turn ignition off and wait a minimum of 5 seconds. DRIVING PATTERN RPM (1) Minutes Idling 3 1/2 1000 3 2000 1 1/2 3000 1 (1) Minimum specification is given.

1. Check vacuum hoses for leaks, blockage and proper routing. Also, check wiring and connectors for damage or poor connections. If problem exists, repair as necessary and perform «TEST DRIVE CONFIRMATION»(ref-91235-S32774063752001030600000). If problem does not exist, go to next step.
2. Check spark at misfiring cylinder. See IGNITION CHECKS in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If problem exists, repair as necessary. If problem does not exist, go to next step.
3. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM connector and measure voltage between ground and fuel injector terminals at ECM harness connector E5. See «IDENTIFYING FUEL INJECTOR TERMINALS»(ref-91235-S00907666642001030600000) table. (Scheme 66) If voltage is 9-14 volts at each terminal, go to step 6. If voltage is not 9-14 volts at each terminal, go to next step. IDENTIFYING FUEL INJECTOR TERMINALS Fuel Injector No. Terminal No. Wire Color 1 12 Red 2 11 White 3 10 Green 4 9 Red/Blue
4. Disconnect fuel injector harness connector at misfiring cylinder. Measure resistance between fuel injector terminals (component side). Resistance should be 13.4-14.2 ohms at 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace fuel injector.
5. Check for open or short in wiring between ECM and fuel injector. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair as necessary. If problem does not exist, repair open or short in injector power source circuit. See appropriate wiring diagram in WIRING DIAGRAMS article.
6. Check fuel pressure. See FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If fuel pressure is not within specification, repair as necessary. If fuel pressure is within specification, go to next step.
7. Check fuel injectors. See FUEL SYSTEM in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, repair as necessary. If problem does not exist, go to next step.
8. Check EGR system components. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, repair as necessary. If problem does not exist, go to next step.
9. Check Mass Airflow (MAF) meter and Engine Coolant Temperature (ECT) sensor. See ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, replace appropriate sensor(s). If problem does not exist, go to next step.
10. Check engine compression. See BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If engine compression is okay, check valve clearance. See ON-VEHICLE ADJUSTMENTS - 4-CYLINDER article. If valve clearance is okay, it may be necessary to check valve timing. See appropriate article in ENGINES.

ECM uses signals provided by crankshaft and camshaft position sensors. If engine speed rate has changed enough to equal a preset number, a misfire is detected and MIL is illuminated. If misfire rate is high enough, and driving conditions will cause catalytic converter damage or overheating, MIL blinks when a misfire is occurring. DTC is set during any particular 200 revolutions of engine during which misfiring is detected which can cause catalytic converter overheating and/or damage or during any particular 1000 revolutions of engine during which misfiring is detected which can cause a deterioration in emission levels. Possible causes are

1. Ignition system malfunction.
2. Defective fuel injector(s).
3. Improper fuel pressure.
4. Defective engine compression.
5. EGR system malfunction.
6. Improper valve clearance.
7. Improper valve timing.
8. Defective Mass Airflow (MAF) meter.
9. Defective Engine Coolant Temperature (ECT) sensor.
10. Open or short in wiring.
11. Poor contact at ECM or component.
12. Defective ECM.

When 2 or more codes for misfiring cylinder are recorded repeatedly but no random misfire code is recorded, it indicates misfires were detected and recorded at different times. If misfire cannot be reproduced, reason may be because of driving with lack of fuel, improper fuel, fouled spark plug, etc. Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

For diagnosis and repair procedure, see DTC P0300: RANDOM MISFIRE DETECTED .

Knock sensor is located on side of cylinder block. Knock sensor generates voltage when engine block vibrates due to knocking. DTC is set when there is no knock sensor signal to ECM with engine speed 1200 RPM or more. Possible causes are

1. Knock sensor circuit is open or shorted.
2. Defective or loose knock sensor.
3. Defective ECM.

Normal mode vibration frequency of knock sensors are 6.6 kHz. Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Access ECM behind glove box. Disconnect ECM harness connector E6. Measure resistance between ground and terminal No. 12 (Gray wire) at ECM harness connector E6. If resistance is one megohm or more, go to step 3 . If resistance is less than one megohm, go to next step.
2. Disconnect knock sensor harness connector. Check continuity between knock sensor body and knock sensor terminal (component side). If continuity exists, replace knock sensor. If continuity does not exist, go to next step.
3. Check for open or short in wiring between knock sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair as necessary. If problem does not exist, go to next step.
4. Substitute suspect knock sensor with known-good knock sensor. Clear DTCs. Start and warm engine to normal operating temperature. Retrieve DTCs. If DTC P0325 is still present, replace ECM. If DTC P0325 is no longer present, replace knock sensor.

CKP sensor is a pick-up coil mounted next to crankshaft pulley. A 34-tooth signal plate is mounted to crankshaft. DTC P0335 is set if no CKP sensor signal is received by ECM during cranking or no CKP sensor signal is received by ECM with engine speed of 600 RPM or more. DTC P1335 is set if no CKP sensor signal is received by ECM with engine speed of 1000 RPM or more. Possible causes are

1. CKP sensor circuit is open or shorted.
2. Defective CKP sensor.
3. Defective signal plate.
4. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Disconnect CKP sensor harness connector. Measure resistance between CKP sensor terminals (component side). Resistance should be 1630-2740 ohms (cold sensor) or 2065-3225 ohms (hot sensor). If resistance is not as specified, replace CKP sensor. If resistance is as specified, go to next step.
2. Check for open or short in wiring between ECM and CKP sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, remove and inspect CKP sensor. Also inspect signal plate. Replace CKP sensor and/or signal plate as necessary. If both components are okay, replace ECM.

CMP sensor is a pick-up coil mounted to outer corner of cylinder head, just below valve cover. A one tooth signal plate is mounted to intake camshaft. DTC is set when no cranking or engine running signal is received by ECM from CMP sensor. Possible causes are

1. CMP sensor circuit is open or shorted.
2. Defective CMP sensor.
3. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Disconnect CMP sensor harness connector. Measure resistance between CMP sensor terminals (component side). Resistance should be 835-1400 ohms (cold sensor) or 1060-1645 ohms (hot sensor). If resistance is as specified, go to next step. If resistance is not as specified, replace CMP sensor.
2. Check for open or short in wiring between ECM and CMP sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
3. Remove and inspect CMP sensor. Also inspect signal plate. If problem exists, replace CMP sensor and/or signal plate as necessary. If problem does not exist, replace ECM.

EGR system recirculates exhaust gas through intake system to reduce combustion temperature and NOx emissions. Amount of EGR valve opening is regulated by EGR vacuum modulator according to engine load. Vacuum source to EGR valve is controlled by EGR Vacuum Switching Valve (VSV), which is controlled by ECM. EGR valve is closed (EGR VSV is on) when engine is not warmed up, vehicle is under deceleration, under light engine load or engine is racing. DTC is set when EGR temperature sensor value does not exceed ambient air temperature by more than 86°F (30°C) after vehicle is operated for 3-5 minutes (50 MPH or more). Possible causes are

1. EGR valve is stuck closed.
2. EGR VSV circuit is shorted.
3. EGR temperature sensor circuit is open.
4. EGR vacuum hose is disconnected.
5. Defective ECM.

1. Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 64) Start and warm engine to normal operating temperature with all accessories off. Operate vehicle at 43-56 MPH for 3 minutes or more. Stop vehicle and allow to idle for about 2 minutes.
2. Operate vehicle at 43-56 MPH for 3 minutes or more. Stop vehicle and allow to idle for about 2 minutes. Turn ignition off. Start engine. Operate vehicle at 43-56 MPH for 3 minutes or more. Stop vehicle and allow to idle for about 2 minutes. Operate vehicle at 43-56 MPH for 3 minutes or more. Stop vehicle and allow to idle for about 2 minutes.
3. Using scan tool, check READINESS TESTS. If COMPL is displayed on scan tool and MIL is not illuminated, system is normal. If INCMPL is displayed and MIL is not illuminated, repeat test drive procedure.

Diagnosis & Repair (Using Toyota Hand-Held Tester)

Note. If EGR gas temperature is 37.6°F (3.1°C), an open exists in EGR temperature sensor circuit.

1. Connect Toyota hand-held tester to Data Link Connector. (Scheme 64) Turn ignition on. Using hand-held tester, read EGR gas temperature. If EGR gas temperature displayed on hand-held tester is 41°F (5°C) or more, go to step 4. If EGR gas temperature displayed on hand-held tester is less than 41°F (5°C), go to next step.
2. Disconnect EGR temperature sensor harness connector. Connect a jumper wire between EGR temperature sensor harness connector terminals. If EGR gas temperature displayed on hand-held tester is not 318.7°F (159.3°C), go to next step. If EGR gas temperature displayed on hand-held tester is 318.7°F (159.3°C), check EGR gas temperature sensor connectors and terminals. Repair as necessary. If connectors are okay, replace EGR temperature sensor.
3. Remove jumper wire. Turn ignition off. Access ECM behind glove box. Connect a jumper wire between terminals No. 9 (Blue/Black wire) and No. 11 (Pink wire) at ECM harness connector E6. Turn ignition on. If EGR gas temperature displayed on hand-held tester is 318.7°F (159.3°C), repair open in wiring between ECM and EGR temperature sensor. If EGR gas temperature displayed on scan tool is not 318.7°F (159.3°C), replace ECM.
4. Check vacuum hoses. See appropriate illustration in VACUUM DIAGRAMS article. If problem exists, replace vacuum hoses as necessary. If problem does not exist, go to next step.
5. Using hand-held tester, select ACTIVE TEST mode. Check operation of EGR VSV when activated by hand-held tester. Apply air pressure to EGR VSV port "E". With EGR system off, air should flow from port "F". (Scheme 69) With EGR system on, air should not flow from port "F". If EGR VSV operates as specified, go to step 8. If EGR VSV does not operate as specified, go to next step.
6. Disconnect EGR VSV harness connector. Measure resistance between EGR VSV terminals (component side). Resistance should be 33-39 ohms at 68°F (20°C). Measure resistance between each terminal and body of EGR VSV. Resistance should be infinite. If resistances are not as specified, replace EGR VSV. If resistances are as specified, go to next step.
7. Apply battery voltage to EGR VSV terminals. Apply air pressure to EGR VSV port "E". Air should flow from port "F". (Scheme 69) Remove battery voltage from EGR VSV terminals. Air should not flow from port "F". If EGR VSV operates as specified, repair open in wiring between EGR VSV and ECM. If EGR VSV does not operate as specified, replace EGR VSV.
8. Check EGR system components. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, repair as necessary. If problem does not exist, go to next step.
9. Check EGR vacuum modulator. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, replace EGR vacuum modulator. If problem does not exist, go to next step.
10. Check EGR valve. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, replace EGR valve. If problem does not exist, go to next step.
11. Ensure all components are connected. Start and run engine. Using hand-held tester, select ACTIVE TEST mode (EGR system ON). Run engine at 4000 RPM for 3 minutes. Monitor EGR gas temperature. If EGR gas temperature displayed on hand-held tester is 212°F (100°C) or more, replace ECM. If EGR gas temperature displayed on hand-held tester is less than 212°F (100°C), replace EGR temperature sensor.

Scheme 69

Diagnosis & Repair (Using OBD-II Scan Tool)

1. Disconnect EGR temperature sensor harness connector. Measure resistance between EGR temperature sensor terminals (component side). If resistance is 600 k/ohms or less, go to next step. If resistance is more than 600 k/ohms, check EGR temperature sensor. See ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. Replace EGR temperature sensor as necessary.
2. Turn ignition on. Measure voltage between EGR temperature sensor harness connector terminals. If voltage is 4.5-5.5 volts, go to step 4. If voltage is not 4.5-5.5 volts, go to next step.
3. Access ECM behind glove box. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 9 (Blue/Black wire) and No. 11 (Pink wire) at ECM harness connector E6. (Scheme 66) Turn ignition on. If voltage is 4.5-5.5 volts, repair open in wiring between EGR temperature sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If voltage is not 4.5-5.5 volts, replace ECM.
4. Check all EGR system vacuum hoses. For proper vacuum hose routing, see appropriate illustration in VACUUM DIAGRAMS article. If problem exists, replace vacuum hoses as necessary. If problem does not exist, go to next step.
5. Access ECM behind glove box. Ensure ignition is off. Disconnect ECM harness connector E6. (Scheme 66) Turn ignition on. Connect a jumper wire between ground and terminal No. 15 (Pink/Blue wire) at ECM harness connector E6. With jumper wire connected, air applied to port "E" of EGR VSV should flow from port "F". (Scheme 69) Disconnect jumper wire. Air applied to port "E" of EGR VSV should not flow from port "F". If EGR VSV operates as specified, go to step 9. If EGR VSV does not operate as specified, go to next step.
6. Turn ignition off. Disconnect EGR VSV harness connector. Measure resistance between EGR VSV terminals. Resistance should be 33-39 ohms at 68°F (20°C). Measure resistance between each terminal and body of EGR VSV. Resistance should be infinite. If resistances are not as specified, replace EGR VSV. If resistances are as specified, go to next step.
7. Apply battery voltage to EGR VSV terminals. Apply air pressure to EGR VSV port "E". Air should flow from port "F". (Scheme 69) Remove battery voltage from EGR VSV terminals. Air should not flow from port "F". If EGR VSV operates as specified, repair open in wiring between EGR VSV and ECM. If EGR VSV does not operate as specified, replace EGR VSV.
8. Check EGR system components. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, repair as necessary. If problem does not exist, go to next step.
9. Check EGR vacuum modulator. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, replace EGR vacuum modulator. If problem does not exist, go to next step.
10. Check EGR valve. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, replace EGR valve. If problem does not exist, go to next step.
11. Disconnect EGR temperature sensor connector. Start engine. Ensure engine is at normal operating temperature. Run engine at 4000 RPM for 3 minutes and measure resistance between EGR temperature sensor terminals (component side). If resistance is 4300 ohms or less, replace ECM. If resistance is more than 4300 ohms, replace EGR temperature sensor.

EGR system recirculates exhaust gas through intake system to reduce combustion temperature and NOx emissions. Amount of EGR valve opening is regulated by EGR vacuum modulator according to engine load. Vacuum source to EGR valve is controlled by EGR Vacuum Switching Valve (VSV), which is controlled by ECM. EGR valve is closed (EGR VSV is on) when engine is not warmed up, vehicle under deceleration, light engine load or engine racing. DTC is set when EGR temperature sensor value does not exceed ambient air temperature by more than 86°F (30°C) after vehicle is operated for 3-5 minutes (50 MPH or more). Possible causes are

1. EGR valve is stuck closed.
2. EGR VSV circuit is shorted.
3. EGR temperature sensor circuit is open.
4. EGR vacuum hose is disconnected.
5. Defective ECM.

1. Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 64) Start and warm engine to normal operating temperature with all accessories off. Operate vehicle at 43-56 MPH for 3 minutes or more. Stop vehicle and allow to idle for about 2 minutes.
2. Operate vehicle at 43-56 MPH for 3 minutes or more. Stop vehicle and allow to idle for about 2 minutes. Turn ignition off. Start engine. Operate vehicle at 43-56 MPH for 3 minutes or more. Stop vehicle and allow to idle for about 2 minutes. Operate vehicle at 43-56 MPH for 3 minutes or more. Stop vehicle and allow to idle for about 2 minutes.
3. Using scan tool, check READINESS TESTS. If COMPL is displayed on scan tool and MIL is not illuminated, system is normal. If INCMPL is displayed and MIL is not illuminated, repeat test drive procedure.

Note. If EGR gas temperature displayed is 318.7°F (159.3°C), a short exists in EGR temperature sensor circuit.

1. Connect Toyota hand-held tester to Data Link Connector. (Scheme 64) Turn ignition on. Using hand-held tester, read EGR gas temperature. If EGR gas temperature displayed on hand-held tester is 302°F (150°C) or less, go to step 4. If EGR gas temperature displayed on hand-held tester is not 302°F (150°C) or less, go to next step.
2. Disconnect EGR temperature sensor harness connector. If EGR gas temperature displayed on hand-held tester is not 37.6°F (3.1°C), go to next step. If EGR gas temperature displayed on hand-held tester is 37.6°F (3.1°C), replace EGR gas temperature sensor.
3. Turn ignition off. Access ECM behind glove box. Disconnect ECM harness connector E6. (Scheme 66) Turn ignition on. Using hand-held tester, read EGR gas temperature. If EGR gas temperature displayed on hand-held tester is 37.6°F (3.1°C), repair open in wiring between ECM and EGR temperature sensor. If EGR gas temperature displayed on hand-held tester is not 37.6°F (3.1°C), replace ECM.
4. Using hand-held tester, select ACTIVE TEST mode. Check operation of EGR VSV when activated by hand-held tester. Apply air pressure to EGR VSV port "E". With EGR system off, air should flow from port "F". (Scheme 69) With EGR system on, air should not flow from port "F". If EGR VSV operates as specified, check EGR valve. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If EGR VSV does not operate as specified, go to next step.
5. Disconnect EGR VSV harness connector. Measure resistance between EGR VSV terminals. Resistance should be 33-39 ohms at 68°F (20°C). Measure resistance between each terminal and body of EGR VSV. Resistance should be infinite. If resistances are not as specified, replace EGR VSV. If resistances are as specified, go to next step.
6. Apply battery voltage to EGR VSV terminals. Apply air pressure to EGR VSV port "E". Air should flow from port "F". (Scheme 69) Remove battery voltage from EGR VSV terminals. Air should not flow from port "F". If EGR VSV operates as specified, repair open in wiring between engine compartment fuse box and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If EGR VSV does not operate as specified, replace EGR VSV.

1. Disconnect EGR temperature sensor harness connector. Measure resistance between EGR temperature sensor terminals (component side). If resistance is 2500 ohms or more, go to next step. If resistance is less than 2500 ohms, replace EGR temperature sensor.
2. Check for short in wiring between EGR temperature sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
3. Access ECM behind glove box. Ensure ignition is off. Disconnect ECM harness connector E6. Turn ignition on. Connect a jumper wire between ground and terminal No. 15 (Pink/Blue wire) at ECM harness connector E6. With jumper wire connected, air applied to port "E" of EGR VSV should flow from port "F". (Scheme 69) Disconnect jumper wire. Air applied to port "E" of EGR VSV should not flow from port "F". If EGR VSV operates as specified, check EGR valve. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If EGR VSV does not operate as specified, go to next step.
4. Turn ignition off. Disconnect EGR VSV harness connector. Measure resistance between EGR VSV terminals. Resistance should be 33-39 ohms at 68°F (20°C). Measure resistance between each terminal and body of EGR VSV. Resistance should be infinite. If resistances are not as specified, replace EGR VSV. If resistances are as specified, go to next step.
5. Apply battery voltage to EGR VSV terminals. Apply air pressure to EGR VSV port "E". Air should flow from port "F". (Scheme 69) Remove battery voltage from EGR VSV terminals. Air should not flow from port "F". If EGR VSV operates as specified, go to next step. If EGR VSV does not operate as specified, replace EGR VSV.
6. Check for open in wiring between engine compartment fuse block and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.

1. If other DTCs are displayed, diagnose and repair those DTCs first and retest system. If only DTC P0420 is displayed, go to next step.
2. Check exhaust system for leaks. If problem exists, repair as necessary. If problem does not exist, go to next step.
3. Check heated oxygen sensor No. 1 circuits. See «DTC P0130: HEATED OXYGEN SENSOR NO. 1 CIRCUIT»(ref-91235-S17808685942001030600000) . If problem exists, repair as necessary. If problem does not exist, go to next step.
4. Check heated oxygen sensor No. 2 circuits. See «DTC P0136: HEATED OXYGEN SENSOR NO. 2 CIRCUIT»(ref-91235-S04407538402001030600000) . If problem exists, repair as necessary. If problem does not exist, replace catalytic converter.

1. Check for cracks, deformations in fuel tank, charcoal canister and fuel tank filler pipe. Check for disconnect hose and tubes around fuel tank and charcoal canister. If problem exists, repair as necessary. If problem does not exist, go to next step.
2. Check fuel cap. If fuel cap is not an OEM cap, replace cap with an OEM cap. If fuel cap is an OEM cap, go to next step.
3. Check if fuel cap is properly installed. If problem exists, install fuel cap properly. If fuel cap is properly installed, go to next step.
4. Check for damaged fuel cap and gasket. If problem exists, replace fuel cap with OEM cap. If problem does not exist, go to next step.
5. Remove fuel cap. Visually inspect fuel tank filler neck for damage. If problem exists, replace fuel tank filler neck as necessary. If problem does not exist, go to next step.
6. Check vacuum hoses between vapor pressure sensor and vapor pressure sensor VSV, and between vapor pressure sensor VSV and charcoal canister. Check hoses for correct installation, looseness and damage. If problem exists, repair vacuum hoses as necessary. If problem does not exist, go to next step.
7. Check hose and tube between fuel tank and charcoal canister for correct installation and damage. If problem exists, repair as necessary. If problem does not exist, go to next step.
8. Visually inspect charcoal canister for cracks, holes and damage. If problem exists, replace charcoal canister. If problem does not exist, go to next step.
9. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 1 (Green/Yellow wire) and No. 9 (Blue/Black wire) at ECM harness connector E6. (Scheme 66) If voltage is not 4.5-5.5 volts, replace ECM. If voltage is 4.5-5.5 volts, go to next step.
10. Using DVOM, backprobe ECM harness connector and measure voltage between terminal No. 10 (Light Green/Black wire) at ECM harness connector E7 and terminal No. 9 (Blue/Black wire) at ECM harness connector E6. (Scheme 66) Disconnect vacuum hose from vapor pressure sensor. Connect a vacuum pump to vapor pressure sensor. Voltage should be 3.0-3.6 volts without vacuum applied and.5 volt or less with 1.18 in. Hg applied. If voltage is as specified, go to step 12. If voltage is not as specified, go to next step.
11. Check for an open or short in wiring between vapor pressure sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace vapor pressure sensor.
12. Connect all previously disconnected components and hoses. Disconnect vacuum hose from charcoal canister (vacuum hose from fuel tank-to-charcoal canister). (Scheme 70) Ensure fuel cap is installed properly. Using apply.71 psi (.05 kg/cm 2 ) pressure to disconnected vacuum hose. If fuel tank does not hold pressure for a minimum of one minute, replace fuel tank as necessary. If fuel tank holds pressure, no fault is indicated at this time. Probable cause of DTC to set was an incorrectly installed fuel cap.

Scheme 70

1. Check EVAP VSV, vapor pressure sensor VSV and vapor pressure sensor harness connectors for damaged pins, corrosion and loose wires. If problem exists, repair connectors as necessary. If problem does not exist, go to next step.
2. Check all EVAP related vacuum hoses for cracks, looseness and correct routing. For proper vacuum hose routing, see appropriate illustration in VACUUM DIAGRAMS article. If problem exists, repair vacuum hoses as necessary. If problem does not exist, go to next step.
3. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 1 (Green/Yellow wire) and No. 9 (Blue/Black wire) at ECM harness connector E6. (Scheme 66) If voltage is not 4.5-5.5 volts, replace ECM. If voltage is 4.5-5.5 volts, go to next step.
4. Using DVOM, backprobe ECM harness connector and measure voltage between terminal No. 10 (Light Green/Black wire) at ECM harness connector E7 and terminal No. 9 (Blue/Black wire) at ECM harness connector E6. (Scheme 66) Disconnect vacuum hose from vapor pressure sensor. Connect a vacuum pump to vapor pressure sensor. Voltage should be 2.9-3.7 volts without vacuum applied and.5 volt or less with 1.18 in. Hg applied. If voltage is as specified, go to step 6. If voltage is not as specified, go to next step.
5. Check for an open or short in wiring between vapor pressure sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace vapor pressure sensor.
6. Connect hand-held tester to Data Link Connector (DLC) No. 3. (Scheme 64) Turn ignition on. Using scan tool, select ACTIVE TEST mode. Disconnect vacuum hose from port "C" (purge port) at charcoal canister. (Scheme 71) Start engine. Connect a vacuum gauge to disconnected vacuum hose. When EVAP VSV is activated by hand-held tester, vacuum should exist. When EVAP VSV is not activated, vacuum should not exist. If vacuum is as specified, go to step 10. If vacuum is not as specified, go to next step.
7. Check vacuum hose between intake manifold and EVAP VSV, and vacuum hose between EVAP VSV and charcoal canister. If problem exists, replace vacuum hoses as necessary. If problem does not exist, go to next step.
8. Check EVAP VSV operation. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, replace EVAP VSV. If problem does not exist, go to next step.
9. Check for an open or short in wiring between EFI main relay, EVAP VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.
10. Turn ignition on. Using hand-held tester, select ACTIVE TEST mode. Disconnect vacuum hoses from vapor pressure sensor VSV. Apply air pressure to vapor pressure sensor VSV port "E". (Scheme 72) When vapor pressure sensor VSV is activated by hand-held tester, air should flow from port "F". When vapor pressure sensor VSV is not activated, air should flow from port "G". If vapor pressure sensor VSV operates as specified, go to step 13. If vapor pressure sensor VSV does not operate as specified, go to next step.
11. Check vapor pressure sensor VSV. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, replace vapor pressure sensor VSV. If problem does not exist, go to next step.
12. Check for open or short in wiring between EFI main relay, vapor pressure sensor VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.
13. Disconnect vapor pressure sensor VSV harness connector. Start engine. Using hand-held tester, select ACTIVE TEST mode. Using DVOM, backprobe ECM harness connector and measure voltage between terminal No. 10 (Light Green/Black wire) at ECM harness connector E7 and terminal No. 9 (Blue/Black wire) at ECM harness connector E6. (Scheme 66) With EVAP VSV activated by hand-held tester, voltage should be 2 volts or less. If voltage is as specified, go to step 15. If voltage is not as specified, go to next step.
14. Check vacuum hose between charcoal canister and vapor pressure sensor VSV, and vacuum hose between vapor pressure sensor and vapor pressure sensor VSV. If problem exists, repair vacuum hoses as necessary. If problem does not exist, go to next step.
15. Remove fuel cap. Disconnect vapor pressure sensor VSV harness connector. Using hand-held tester, select ACTIVE TEST mode. Start engine. Using DVOM, backprobe ECM harness connector and measure voltage between terminal No. 10 (Light Green/Black wire) at ECM harness connector E7 and terminal No. 9 (Blue/Black wire) at ECM harness connector E6 5 seconds after switching EVAP VSV from on to off. If voltage is 2.5 volts or less, replace charcoal canister. If voltage is more than 2.5 volts, go to next step.
16. Perform appropriate fuel EVAP system test. See FUEL EVAPORATION SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, repair as necessary. If problem does not exist, replace ECM.

Scheme 71

Scheme 72

1. Check EVAP VSV, vapor pressure sensor VSV and vapor pressure sensor connectors for damaged pins, corrosion and loose wires. If problem exists, repair connectors as necessary. If problem does not exist, go to next step.
2. Check all EVAP related vacuum hoses for cracks, looseness and correct routing. For proper vacuum hose routing, see appropriate illustration in VACUUM DIAGRAMS article. If problem exists, repair vacuum hoses as necessary. If problem does not exist, go to next step.
3. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 1 (Green/Yellow wire) and No. 9 (Blue/Black wire) at ECM harness connector E6. (Scheme 66) If voltage is not 4.5-5.5 volts, replace ECM. If voltage is 4.5-5.5 volts, go to next step.
4. Using DVOM, backprobe ECM harness connector and measure voltage between terminal No. 10 (Light Green/Black wire) at ECM harness connector E7 and terminal No. 9 (Blue/Black wire) at ECM harness connector E6. (Scheme 66) Disconnect vacuum hose from vapor pressure sensor. Connect a vacuum pump to vapor pressure sensor. Voltage should be 2.9-3.7 volts without vacuum applied and.5 volt or less with 1.18 in. Hg applied. If voltage is as specified, go to step 6. If voltage is not as specified, go to next step.
5. Check for open or short in wiring between vapor pressure sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace vapor pressure sensor.
6. Disconnect EVAP VSV vacuum hoses. Apply air pressure to EVAP VSV port "E". (Scheme 69) Air should not flow from port "F". Access ECM behind glove box. Turn ignition on. Using a jumper wire, backprobe between ground and terminal No. 3 (Black/White wire) at ECM harness connector E5. (Scheme 66) Air should flow from port "F". If EVAP VSV operates as specified, go to step 10. If EVAP VSV does not operate as specified, go to next step.
7. Check vacuum hose between intake manifold and EVAP VSV, and vacuum hose between EVAP VSV and charcoal canister. If problem exists, replace vacuum hoses as necessary. If problem does not exist, go to next step.
8. Check EVAP VSV. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, replace EVAP VSV. If problem does not exist, go to next step.
9. Check for open or short in wiring between EFI main relay, EVAP VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.
10. Disconnect vapor pressure sensor VSV vacuum hoses. Apply air pressure to vapor pressure sensor VSV port "E". (Scheme 72) Air should flow from port "G". Access ECM behind glove box. Turn ignition on. Using a jumper wire, backprobe between ground and terminal No. 8 (Red/Black wire) at ECM harness connector E6. (Scheme 66) Air should flow from port "F". If vapor pressure sensor VSV does not operate as specified, go to next step. If vapor pressure sensor VSV operates as specified, check charcoal canister. Perform appropriate fuel EVAP system test. See FUEL EVAPORATION SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article.
11. Check vapor pressure sensor VSV. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, replace vapor pressure sensor VSV. If problem does not exist, go to next step.
12. Check for open or short in wiring between EFI main relay, vapor pressure sensor VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair wiring harness as necessary. If problem does not exist, replace ECM.

Vapor pressure sensor and vapor pressure sensor Vacuum Switching Valve (VSV) are used to detect faults in EVAP system. DTC is set if vapor pressure sensor malfunctions. Possible causes are

1. Vapor pressure sensor circuit is open or shorted.
2. Defective vapor pressure sensor.
3. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between terminals No. 1 (Green/Yellow wire) and No. 9 (Blue/Black wire) at ECM harness connector E6. (Scheme 66) If voltage is not 4.5-5.5 volts, replace ECM. If voltage is 4.5-5.5 volts, go to next step.
2. Using DVOM, backprobe ECM harness connector and measure voltage between terminal No. 10 (Light Green/Black wire) at ECM harness connector E7 and terminal No. 9 (Blue/Black wire) at ECM harness connector E6. (Scheme 66) Disconnect vacuum hose from vapor pressure sensor. Connect a vacuum pump to vapor pressure sensor. Voltage should be 2.9-3.7 volts without vacuum applied and.5 volt or less with 1.18 in. Hg applied. If voltage is as specified, replace ECM. If voltage is not as specified, go to next step.
3. Check for open or short in wiring between vapor pressure sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace vapor pressure sensor.

VSS outputs a 4-pulse signal for every revolution of the rotor shaft, which is driven by transaxle output shaft. Signal is sent to instrument cluster to operate speedometer. Instrument cluster then sends signal to ECM. Signal is used by ECM to determine vehicle speed. DTC is set if there is no VSS signal to ECM while vehicle is being driven and park/neutral switch is off. Possible causes are

1. Defective vehicle speed sensor.
2. VSS circuit is open or shorted.
3. Defective instrument cluster.
4. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Test drive vehicle and check operation of speedometer. If speedometer is not operating correctly, repair speedometer as necessary. See appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. If speedometer is operating correctly, go to next step.
2. Access ECM behind glove box. Raise and support one rear wheel. Turn ignition on. Shift transaxle lever into Neutral. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 8 (Green/Orange wire) at ECM harness connector E8. (Scheme 66) Observe voltage reading while rotating rear wheel. Voltage should pulse between zero volts and 4.5-5.5 volts. If voltage is as specified, replace ECM. If voltage is not as specified, repair open or short in wiring between instrument cluster and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article.

ECM operates IAC valve to perform idle-up and provide feedback for target idling speed. DTC is set when idle speed continues to vary greatly from target speed. Possible causes are

1. Idle Air Control (IAC) valve is stuck, or remains closed.
2. IAC valve circuit is open or shorted.
3. A/C switch circuit is open or shorted.
4. Air induction system malfunction.
5. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Start engine and warm to normal operating temperature. Turn all accessories off. Ensure A/C is off. Shift transaxle lever into Neutral. Connect scan tool to Data Link Connector (DLC) No. 3. (Scheme 64) Note engine RPM. Using a jumper wire, connect terminals TE1 and E1 at DLC No. 1 in engine compartment. (Scheme 73) Note engine RPM and compare RPM readings. If difference in engine speed is more than 100 RPM, go to step 6. If difference in engine speed is 100 RPM or less, go to next step.
2. Turn ignition off. Access ECM behind glove box. Disconnect ECM harness connector E5. (Scheme 66) Turn ignition on. Measure voltage between ground and terminals No. 7 (Brown/Red wire) and No. 6 (Pink/Blue wire) at ECM harness connector E5. If both readings are 9-14 volts, go to step 4. If either reading is not 9-14 volts, go to next step.
3. Turn ignition off. Disconnect IAC valve harness connector. Measure resistance between terminal No. 2 and terminals No. 1 and 3 at IAC valve (component side). (Scheme 74) If resistance is not 17-25 ohms (cold) or 22-29 ohms (hot), replace IAC valve. If resistance is 17-25 ohms (cold) or 22-29 ohms (hot), repair open or short in wiring between IAC valve and ECM, or between IAC valve and EFI main relay. See appropriate wiring diagram in WIRING DIAGRAMS article.
4. Check IAC valve operation. See IDLE CONTROL SYSTEM in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, replace IAC valve. If problem does not exist, go to next step.
5. Remove IAC valve from throttle body. Check IAC valve and passages for carbon build-up and blockage. If problem exists, repair or replace as necessary. If problem does not exist, replace ECM.
6. Ensure oil dipstick, oil filler cap, PCV system and all other air induction system components are intact and operating properly. If problem exists, repair as necessary. If problem does not exist, an open or short in A/C switch signal circuit may exist. Check A/C amplifier. See appropriate article in AIR CONDITIONING & HEATING. Repair as necessary.

Scheme 73

Scheme 74

Direct Ignition System (DIS) is a 2-cylinder ignition system that ignites 2 cylinders with one ignition coil. Ignitor is integral to ignition coil. ECM determines ignition timing and outputs an ignition signal (IGT). Based on IGT signal, power transistors in ignitor cuts off current to primary coil in ignition coil, causing ignition coil to fire spark plug. After delivering a command to turn off primary circuit on IGT wire, ECM monitors IGF circuit to ensure primary switching occurs. DTC is set when there is no IGF signal to ECM during engine operation. Possible causes are

1. IGF or IGT circuit from ignitor to ECM is open or shorted.
2. Defective ignition coil/ignitor No. 1.
3. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Check for spark at misfiring cylinder. See IGNITION CHECKS in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If spark is exists, go to next step. If spark is not exist, go to step 4.
2. Check for open or short in Black/Yellow wire between terminal No. 17 at ECM harness connector E5 and both ignition coil/ignitors. Check for open or short in Black/Blue wire between terminal No. 23 at ECM harness connector E5 and ignition coil/ignitor No. 1. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
3. Disconnect both ignition coil/ignitor harness connector. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe at ECM harness connector and measure voltage between ground and terminal No. 17 (Black/Yellow wire) at ECM harness connector E5. (Scheme 66) If voltage is 4.5-5.5 volts, replace ignition coil/ignitor No. 1. If voltage is not 4.5-5.5 volts, replace ECM.
4. Check for open or short in Black/Blue wire between terminal No. 23 at ECM harness connector E5 and ignition coil/ignitor No. 1. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
5. Access ECM behind glove box. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 23 (Black/Blue wire) at ECM harness connector E5 while cranking engine. (Scheme 66) If voltage is.1-4.5 volts, go to next step. If voltage is not.1-4.5 volts, replace ECM.
6. Disconnect ignition coil/ignitor No. 1 harness connector. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 23 (Black/Blue wire) at ECM harness connector E5 while cranking engine. If voltage is.1-4.5 volts, go to next step. If voltage is not.1-4.5 volts, replace ECM.
7. Turn ignition on. Measure voltage between ground and terminal No. 1 (Black/Red wire) at ignition coil/ignitor No. 1 harness connector with ignition switch in ON and START positions. (Scheme 75) If voltages are 9-14 volts, go to next step. If voltages are not 9-14 volts, check and repair ignition coil/ignitor No. 1 power source circuit. See appropriate wiring diagram in WIRING DIAGRAMS article.
8. Check for open in Brown wire between ground and ignition coil/ignitor No. 1. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace ignition coil/ignitor No. 1.

Scheme 75

Direct Ignition System (DIS) is a 2-cylinder ignition system that ignites 2 cylinders with one ignition coil. Ignitor is integral to ignition coil. ECM determines ignition timing and outputs an ignition signal (IGT). Based on IGT signal, power transistors in ignitor cuts off current to primary coil in ignition coil, causing ignition coil to fire spark plug. After delivering a command to turn off primary circuit on IGT wire, ECM monitors IGF circuit to ensure primary switching occurs. DTC is set when there is no IGF signal to ECM during engine operation. Possible causes are

1. IGF or IGT circuit from ignitor to ECM is open or shorted.
2. Defective ignition coil/ignitor No. 2.
3. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Check for spark at misfiring cylinder. See IGNITION CHECKS in BASIC DIAGNOSTIC PROCEDURES - 4-CYLINDER article. If spark is exists, go to next step. If spark is not exist, go to step 4.
2. Check for open or short in Black/Yellow wire between terminal No. 17 at ECM harness connector E5 and both ignition coil/ignitors. Check for open or short in Yellow/Black wire between terminal No. 22 at ECM harness connector E5 and ignition coil/ignitor No. 2. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
3. Disconnect both ignition coil/ignitor harness connector. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe at ECM harness connector and measure voltage between ground and terminal No. 17 (Black/Yellow wire) at ECM harness connector E5. (Scheme 66) If voltage is 4.5-5.5 volts, replace ignition coil/ignitor No. 2. If voltage is not 4.5-5.5 volts, replace ECM.
4. Check for open or short in Yellow/Black wire between terminal No. 22 at ECM harness connector E5 and ignition coil/ignitor No. 2. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, go to next step.
5. Access ECM behind glove box. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 22 (Yellow/Black wire) at ECM harness connector E5 while cranking engine. (Scheme 66) If voltage is.1-4.5 volts, go to next step. If voltage is not.1-4.5 volts, replace ECM.
6. Disconnect ignition coil/ignitor No. 2 harness connector. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 22 (Yellow/Black wire) at ECM harness connector E5 while cranking engine. If voltage is.1-4.5 volts, go to next step. If voltage is not.1-4.5 volts, replace ECM.
7. Turn ignition on. Measure voltage between ground and terminal No. 1 (Black/Red wire) at ignition coil/ignitor No. 2 harness connector with ignition switch in ON and START positions. (Scheme 75) If voltages are 9-14 volts, go to next step. If voltages are not 9-14 volts, check and repair ignition coil/ignitor No. 2 power source circuit. See appropriate wiring diagram in WIRING DIAGRAMS article.
8. Check for open in Brown wire between ground and ignition coil/ignitor No. 2. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace ignition coil/ignitor No. 2.

1. Check stoplight operation. If stoplights do not operate properly, repair as necessary and retest system. See appropriate wiring diagram in EXTERIOR LIGHTS article in ACCESSORIES & EQUIPMENT. If stoplights operate properly, go to next step.
2. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 21 (Green/White wire) at ECM harness connector E8. (Scheme 66) Voltage should be 7.5-14.0 volts with brake pedal depressed and less than 1.5 volts with brake pedal released. If voltage is not as specified, go to next step. If voltage is as specified, problem is intermittent. Check component and ECM connections.
3. Check for short in wiring between ECM and stoplight switch. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.

Battery voltage is supplied to ECM BATT terminal (constant). DTC is set when open in back-up power source is detected. Possible causes are

1. Back-up power source circuit is open.
2. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

1. Turn ignition off. Access ECM behind glove box. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 2 (Blue/Red wire) at ECM harness connector E8. (Scheme 66) If voltage is 9-14 volts, replace ECM. If voltage is not 9-14 volts, go to next step.
2. Remove and inspect EFI fuse (20-amp) in engine compartment fuse box. If fuse is blown, check for short to ground in wiring between EFI fuse and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary and replace fuse. If fuse is okay, check for open in wiring between EFI fuse and ECM. Repair as necessary.

PNP switch sends a signal to ECM when transaxle is in Neutral or Park. This signal is used for air/fuel correction and for idle speed control. DTC is set when 2 or more switches are on simultaneously for "R", "N", "2" and "L" position, or ECM is receiving an ON signal from PNP switch when vehicle is being operated for more than 30 seconds at 44 MPH or more (1500-2500 RPM). Possible causes are

1. PNP switch circuit is shorted.
2. Defective PNP switch.
3. Defective ECM.

Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.

Note. Toyota hand-held tester can be used to confirm PNP switch signal from CURRENT DATA.

1. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between ground and specified terminal at ECM harness connector E8 with shift lever in appropriate position. See «PARK/NEUTRAL POSITION SWITCH VOLTAGE»(ref-91235-S10466649882001030600000) table. (Scheme 66) If voltage is as specified, no problem is indicated at this time. If voltage is not as specified, go to next step. PARK/NEUTRAL POSITION SWITCH VOLTAGE Shift Lever Position Terminal No. Volts Park & Neutral 15 Zero 16 Zero 17 Zero 22 Zero Reverse 15 Zero 16 Zero 17 (1) 9-14 22 (1) 9-14 Drive 15 Zero 16 Zero 17 Zero 22 9-14 2 15 Zero 16 9-14 17 Zero 22 9-14 Low 15 9-14 16 Zero 17 Zero 22 9-14 (1) Voltage may be slightly less due to lighting of reverse lights.
2. Disconnect PNP switch harness connector. Check continuity between appropriate PNP switch terminals (component side) with shift lever in appropriate position. See «PARK/NEUTRAL POSITION SWITCH CONTINUITY»(ref-91235-S26374517012001030600000) table. (Scheme 76) If problem exists, replace PNP switch. If problem does not exist, go to next step. PARK/NEUTRAL POSITION SWITCH CONTINUITY Shift Lever Position Continuity Between Terminals No. Park 4 & 7; 5 & 6 Reverse 4 & 8 Neutral 4 & 10; 5 & 6 Drive 4 & 9 2 2 & 4 Low 3 & 4
3. Check wiring between battery and PNP switch and between PNP switch and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.

Scheme 76