Engine Control System Tests W/codes - 4-Cylinder: Diagnosis Toyota Camry XV20

DIAGNOSTIC TROUBLE CODE DEFINITIONS

DIAGNOSTIC TROUBLE CODE (DTC) DEFINITIONS

Diagnosis & Repair

1. If any codes other than DTC P0106 are displayed, diagnose and repair those codes first. If only DTC P0106 is displayed, go to next step.
2. Check MAP sensor. See appropriate SYSTEM/COMPONENT TESTS article. Replace sensor as necessary. If sensor is okay, check vacuum hose to sensor. Replace vacuum hose as necessary and retest.

1. Connect scan tool to DLC No. 3 connector. see scheme 1 Turn ignition on. Using scan tool, monitor IAT sensor temperature. If temperature displayed is same as outside temperature, check component and ECM connections. Problem is intermittent.
2. If temperature displayed is 284°F (140°C) or more, go to step 5). If temperature displayed is -40°F (-40°C), turn ignition off. Disconnect IAT sensor connector. Connect a jumper wire between IAT sensor wiring harness connector terminals. Turn ignition on. Using scan tool, monitor IAT sensor temperature.
3. If temperature displayed is 284°F (140°C) or more, replace IAT sensor. If temperature displayed is less than 284°F (140°C), turn ignition off. Remove jumper wire. Access ECM behind glove box. Connect a jumper wire between terminals No. 3 (Yellow/Black wire) and No. 9 (Brown wire) at ECM E8 connector. see scheme 2or see scheme 3.
4. If temperature displayed on scan tool is 284°F (140°C) or more, check for open circuit in wiring harness between IAT sensor connector and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If temperature displayed on scan tool is less than 284°F (140°C), replace ECM.
5. Turn ignition off. Disconnect IAT sensor connector. Turn ignition on. If temperature displayed on scan tool is -40°F (-40°C), replace IAT sensor. If temperature displayed is not -40°F (-40°C), turn ignition off.
6. Access ECM behind glove box. Disconnect ECM E8 connector. see scheme 2or see scheme 3. Turn ignition on. If temperature displayed on scan tool is-40°F (-40°C), check and repair wiring harness between IAT 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. Connect scan tool to DLC No. 3 connector. see scheme 1 Turn ignition on. Using scan tool, monitor ECT sensor temperature. If temperature displayed is same as actual coolant temperature, check component and ECM connections. Problem is intermittent.
2. If temperature displayed is 284°F (140°C) or more, go to step 5). If temperature displayed is -40°F (-40°C), turn ignition off. Disconnect ECT sensor connector. Connect a jumper wire between ECT sensor wiring harness connector terminals. Turn ignition on. Using scan tool, monitor ECT sensor temperature.
3. If temperature displayed is 284°F (140°C) or more, replace ECT sensor. If temperature displayed is less than 284°F (140°C), turn ignition off. Remove jumper wire. Access ECM behind glove box. Connect a jumper wire between terminals No. 4 (Green/Black wire) and No. 9 (Brown wire) at ECM E8 connector. see scheme 2or see scheme 3.
4. If temperature displayed on scan tool is 284°F (140°C) or more, locate and repair open circuit in wiring harness 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.
5. Turn ignition off. Disconnect ECT sensor connector. Turn ignition on. If temperature displayed on scan tool is -40°F (-40°C), replace ECT sensor. If temperature displayed is not -40°F (-40°C), turn ignition off.
6. Access ECM behind glove box. Disconnect ECM E8 connector. see scheme 2or see scheme 3. Turn ignition on. If temperature displayed is -40°F (-40°C), locate and repair short circuit in wiring harness between ECT sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If temperature displayed by scan tool is not -40°F (-40°C), replace ECM.

Circuit Description

The ECT sensor is a thermistor sensor that monitors engine coolant temperature. DTC is set when ECT sensor signal value is out of range during engine operation. Possible causes are

1. ECT sensor.
2. Cooling system.

Note. If DTCs P0115 and P0116 are output together, an open may exist in ECT sensor circuit. Perform DTC P0115 test before performing DTC P0116 test.

If any other codes are displayed, diagnose and repair those codes first and retest. If only DTC P0116 is displayed, remove and inspect cooling system thermostat. Replace thermostat as necessary and retest system. If thermostat is okay, replace ECT sensor.

1. Connect scan tool to DLC No. 3 connector. see scheme 1 Turn ignition on. Using scan tool, monitor throttle valve opening percentage. Opening percentage should be approximately 10 percent with fully closed throttle.
2. Depress accelerator pedal to floor (WOT). Opening percentage should be approximately 70 percent. If percentages are as specified, check all connections. Problem may be intermittent.
3. If percentages are not as specified, turn ignition off. Disconnect TP sensor connector. Turn ignition on. Using DVOM, measure voltage between ground and terminal No. 1 (Yellow wire) at TP sensor wiring 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 7).
4. Check TP sensor. See ENGINE SENSORS & SWITCHES in appropriate SYSTEM/COMPONENT TESTS article. Replace sensor as necessary. If sensor is okay, go to next step.
5. Access ECM behind glove box. Turn ignition on. Backprobing ECM connector, measure voltage between terminals No. 9 (Brown wire) and No. 11 (Light Green wire) at ECM E8 connector. see scheme 2or see scheme 3. Voltage should be.3-.8 volt with throttle fully closed, and 3.2-4.9 volts with throttle fully open (WOT).
6. If voltage is as specified, replace ECM. If voltage is not as specified, check for an open or short circuit in wiring harness between TP sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary.
7. Access ECM behind glove box. Turn ignition on. Backprobing ECM connector, measure voltage between terminals No. 1 (Yellow wire) and No. 9 (Brown wire) at ECM E8 connector. see scheme 2or see scheme 3. If voltage is 4.5-5.5 volts, check wiring harness for an open in Yellow wire. If voltage is not 4.5-5.5 volts, replace ECM.

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

1. Connect scan tool to DLC No. 3 connector. see scheme 1 Start vehicle and warm engine to normal operating temperature. Using scan tool, monitor heated oxygen sensor No. 1. Snap accelerate engine 3 times. Sensor should indicate a rich signal (.45 volt or more) at least once.
2. If a rich signal is indicated at least once, replace ECM. If sensor does not display a rich signal at least once, perform misfire diagnosis. See «DTCS P0301-P0304»(ref-22531-S00761197642001010300000): CYLINDERS NO. 1-4 MISFIRE DETECTED test. Repair as necessary. If no misfire is detected, go to next step.
3. Check for open or short circuit in wiring harness between ECM and heated oxygen sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace heated oxygen sensor.

Test Drive Confirmation

1. If using OBD-II scan tool, go to next step. If using Toyota scan tool, connect scan tool. see scheme 1 Switch scan tool to CHECK mode. Start and warm engine to normal operating temperature. Drive vehicle at 38-65 MPH with engine speed at 1600-3200 RPM for 3-5 minutes. If malfunction exists, MIL will illuminate.
2. If using OBD-II scan tool, start and warm engine to normal operating temperature. Drive vehicle at 38-65 MPH with engine speed at 1600-3200 RPM for 3-5 minutes. Stop vehicle and turn ignition off. Repeat driving part of test. If malfunction exists, MIL will illuminate.

1. If only DTC P0125 is displayed, go to next step. If other codes are displayed, diagnose and repair those codes first and retest system.
2. Perform misfire diagnosis. See «DTCS P0301-P0304»(ref-22531-S00761197642001010300000) : CYLINDERS NO. 1-4 MISFIRE DETECTED test. Repair as necessary. If no misfire is detected, go to next step.
3. Check for open or short circuit in wiring harness between ECM and AFS. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring is okay, go to next step.
4. Disconnect AFS connector. AFS is located in exhaust manifold. Using ohmmeter, measure resistance between Black/Yellow wire and Green wire at AFS connector. Resistance should be 11-16 ohms at 68°F (20°C). Replace AFS as necessary. If resistance is 11-16 ohms, go to next step.
5. Reconnect AFS connector. Start engine and raise engine speed to 2500 RPM for 90 seconds. Using scan tool, monitor AFS output voltage. See «AIR/FUEL RATIO SENSOR SPECIFICATIONS»(ref-22531-S36372290932001010300000) table. If voltage is as specified, go to next step. If voltage is not as specified, replace AFS. AIR/FUEL RATIO SENSOR SPECIFICATIONS Application (1) Voltage Using OBD-II Scan Tool Engine Idling 0.66 Engine Racing 0.76 Or More Driving Vehicle (2) 0.56 Or Less Using Toyota Scan Tool Engine Idling 3.3 Engine Racing 3.8 Or More Driving Vehicle (2) 2.8 Or Less (1) Voltage should not remain at specification given. (2) Drive vehicle at 25 MPH or more with engine speed at 1500 RPM or more while opening and closing throttle valve.
6. Perform TEST DRIVE CONFIRMATION. If DTC P0125 resets, replace ECM. If DTC P0125 does not reset, no problem is indicated at this time.

1. If using OBD-II scan tool, go to next step. If using Toyota scan tool, connect scan tool. see scheme 1 Switch scan tool to CHECK mode. Start and warm engine to normal operating temperature. Drive vehicle at 31-40 MPH for 1-3 minutes. Stop vehicle and allow to idle for one minute. If malfunction exists, MIL will illuminate.
2. If using OBD-II scan tool, start and warm engine to normal operating temperature. 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.

Diagnosis & Repair Procedure

1. Check for open or short circuit in wiring harness between ECM and oxygen sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, connect scan tool. see scheme 1
2. Start engine and warm to normal operating temperature. Monitor oxygen sensor output voltage and short-term fuel trim. If scan tool indicates a lean condition (.6 volt or less, +20 trim) or rich condition (.4 volt or more, -20 trim), see appropriate DTC P0171 OR P0172.: SYSTEM TOO LEAN/RICH test.
3. If scan tool indicates other than reading in step 2), operate engine at 2500 RPM for 90 seconds. Allow engine to idle and monitor oxygen sensor voltage. If voltage constantly fluctuates from less than.4 volt to.6 volt or more, perform TEST DRIVE CONFIRMATION. If voltage does not fluctuate as specified, replace sensor.

If only DTC P0133 is displayed, replace oxygen sensor. If other codes are displayed, diagnose and repair those codes first and retest.

1. On models with engine immobilizer system, go to next step. On models without engine immobilizer system, access ECM harness connectors behind glove box. Turn ignition on. Using DVOM, backprobe ECM harness connector. If DTC P0135 is set, measure voltage between ground and terminal No. 8 (Blue/Yellow wire) at ECM E9 connector. If DTC P0141 is set, measure voltage between ground and terminal No. 21 (Pink/Black wire) at ECM E9 connector. see scheme 2 Go to step 3). NOTE: For information on engine immobilizer system, see COMPUTERIZED ENGINE CONTROLS in THEORY/OPERATION article.
2. On models with engine immobilizer system, access ECM harness connectors behind glove box. Turn ignition on. Using DVOM, backprobe ECM harness connector. If DTC P0135 is set, measure voltage between ground and terminal No. 1 (Blue/Yellow wire) at ECM E9 connector. see scheme 3 If DTC P0141 is set, measure voltage between ground and terminal No. 14 (Pink/Black wire) at ECM E9 connector. Go to next step.
3. On all models, if voltage is 9-14 volts, replace ECM. If voltage is not 9-14 volts, turn ignition off. Disconnect appropriate oxygen sensor harness connector. Using ohmmeter, measure resistance between terminals No. 1 and 2 at oxygen sensor connector. See «IDENTIFYING OXYGEN SENSOR HEATER TERMINALS»(ref-22531-S07475888832001010300000) table. IDENTIFYING OXYGEN SENSOR HEATER TERMINALS Application Terminal No. 1 Terminal No. 2 Sensor No. 1 Blue/Yellow Wire Black/Yellow Wire Sensor No. 2 Pink/Black Wire Black/Yellow Wire
4. With sensor temperature at 68°F (20°C), resistance should be 11-16 ohms. If resistance is as specified, check circuits between EFI main relay, sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If resistance is not as specified, replace oxygen sensor.

1. If any other codes are displayed other than DTC P0136, diagnose and repair those codes first. If only DTC P0136 is displayed, check for open or short circuit in wiring harness between ECM and sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary.
2. If wiring harness is okay, connect scan tool. see scheme 1 Start and warm engine to normal operating temperature. Monitor sensor No. 2 output voltage. Snap accelerate engine 3 times. Voltage should fluctuate from less than.4 volt to.5 volt or more.
3. If voltage fluctuates as specified, check sensor wiring harness connector. Problem may be intermittent. If voltage does not fluctuate as specified, replace oxygen sensor.

1. Check all air induction components. Repair as necessary. If air induction components are okay, connect scan tool. see scheme 1 Start engine and warm to normal operating temperature. Using scan tool, monitor AFS output voltage and short-term fuel trim. If using OBD-II, scan tool, go to step 3). If using Toyota scan tool, go to next step.
2. If Toyota scan tool indicates a lean condition (.6 volt or less, -20 trim) or rich condition (.8 volt or more, +20 trim), go to step 4). If results are other than shown, check AFS. See appropriate SYSTEM/COMPONENT TESTS article.
3. If OBD-II scan tool indicates a lean condition (2.8 volts or less, +20 trim) or rich condition (3.8 volts or more, -20 trim), go to next step. If results are other than shown, check AFS. See appropriate SYSTEM/COMPONENT TESTS article.
4. Check fuel pressure. See appropriate BASIC TESTING article. Repair fuel pressure as necessary. If fuel pressure is okay, check fuel injectors. See appropriate SYSTEM/COMPONENT TESTS article. Replace injectors as necessary.
5. If injectors are okay, check Manifold Absolute Pressure (MAP) sensor and Engine Coolant Temperature (ECT) sensor. See appropriate SYSTEM/COMPONENT TESTS article. Replace MAP and/or ECT sensor as necessary. If both components are okay, check ignition system. See IGNITION CHECKS in appropriate BASIC TESTING article. Repair ignition system as necessary. If ignition system is okay, replace ECM.

1. Check all air induction components. Repair as necessary. If air induction components are okay, connect scan tool. see scheme 1 Start engine and warm to normal operating temperature. Monitor heated oxygen sensor No. 1 output voltage and short-term fuel trim.
2. If scan tool indicates a lean condition (.6 volt or less, +20 trim) or rich condition (.4 volt or more, -20 trim), go to next step. If results are other than shown, see «DTC P0130»(ref-22531-S08328140232001010300000): OXYGEN SENSOR NO. 1 CIRCUIT (EXCEPT CALIF. EMISSIONS) test.
3. Check fuel pressure. See appropriate BASIC TESTING article. Repair fuel pressure as necessary. If fuel pressure is okay, check fuel injectors. See appropriate SYSTEM/COMPONENT TESTS article. Replace injectors as necessary.
4. If injectors are okay, check Manifold Absolute Pressure (MAP) sensor and Engine Coolant Temperature (ECT) sensor. See appropriate SYSTEM/COMPONENT TESTS article. Replace MAP and/or ECT sensor as necessary. If both components are okay, check ignition system. See IGNITION CHECKS in appropriate BASIC TESTING article. Repair ignition system as necessary. If ignition system is okay, replace ECM.

A misfire is determined by the ECM. The ECM uses signals provided by the crankshaft and camshaft position sensors. If the engine speed rate has changed enough to equal a preset number, a misfire is detected and the MIL is illuminated. If the misfire rate is high enough, and driving conditions will cause catalytic converter damage or overheating, the 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.
2. Injector(s).
3. Fuel pressure.
4. EGR system.
5. Engine compression.
6. Valve clearance.
7. Valve timing.
8. Manifold Absolute Pressure (MAP) sensor.
9. Engine Coolant Temperature (ECT) sensor.

1. Inspect spark plug and check for spark at misfiring cylinder. See appropriate BASIC TESTING article. Repair as necessary. If spark plug is okay and spark is present, go to next step.
2. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM connector. Measure voltage between ground and injector terminals at ECM E9 connector. See «IDENTIFYING INJECTOR TERMINALS»(ref-22531-S25979510072001010300000) table. see scheme 2or see scheme 3. If voltage is 9-14 volts for each circuit, go to step 4). If voltage is not 9-14 volts, go to next step. IDENTIFYING INJECTOR TERMINALS Injector No. (1) Terminal No. Wire Color 1 12 Blue 2 11 Red 3 With Engine Immobilizer System 10 Yellow Without Engine Immobilizer System 25 Yellow 4 With Engine Immobilizer System 9 White Without Engine Immobilizer System 24 White (1) Terminals are located in ECM E9 connector.
3. Disconnect injector of misfiring cylinder. Using ohmmeter, measure resistance between injector terminals. If resistance is 13.4-14.2 ohms, check for open or short circuit in wiring harness between ECM and injector. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If resistance is not 13.4-14.2 ohms, replace injector.
4. Check fuel pressure. See appropriate BASIC TESTING article. Repair fuel pressure as necessary. If fuel pressure is okay, check fuel injector performance. See appropriate SYSTEM/COMPONENT TESTS article. Replace fuel injectors as necessary.
5. If all injectors are okay, check EGR system. See appropriate SYSTEM/COMPONENT TESTS article. Repair EGR system as necessary. If EGR system is okay, check MAP sensor and ECT sensor. See appropriate SYSTEM/COMPONENT TESTS article. Replace MAP and/or ECT sensor as necessary. If both components are okay, also check engine compression, valve clearance and valve timing. See appropriate BASIC TESTING article.

See DTC P0300 : RANDOM MISFIRE DETECTED test.

See DTC P0300 : RANDOM MISFIRE DETECTED test.

1. Access ECM behind glove box. Disconnect ECM E8 connector. see scheme 2or see scheme 3. On models with engine immobilizer system, backprobe ECM connector and measure resistance between ground and terminal No. 12 (White wire) at ECM E8 connector. see scheme 3 On models without engine immobilizer system, backprobe ECM connector and measure resistance between ground and terminal No. 13 (White wire) at ECM E8 connector. see scheme 2 On all models, if resistance is infinity, go to step 3). If resistance is not infinity, go to next step. NOTE: For information on engine immobilizer system, see COMPUTERIZED ENGINE CONTROLS in THEORY/OPERATION article.
2. Disconnect knock sensor connector. Check continuity between sensor terminal and sensor housing. If continuity does not exist, go next step. If continuity exists, replace knock sensor.
3. Check for open or short circuit in wiring harness between knock sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, substitute knock sensor with known-good sensor. Clear and then retrieve codes. See SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article. If code is still present, replace ECM. If code is no longer present, replace knock sensor.

1. Disconnect CKP sensor connector. Using ohmmeter, measure resistance between CKP sensor connector terminals. Resistance should be 985-1600 ohms (cold sensor) or 1265-1890 ohms (hot sensor). Replace CKP sensor as necessary. If CKP sensor is okay, go to next step.
2. Check for open or short circuit in wiring harness between ECM and CKP sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, remove and inspect CKP sensor. Also inspect crankshaft timing pulley teeth. Replace CKP sensor and/or crankshaft timing pulley as necessary. If both components are okay, replace ECM.

1. Disconnect CMP sensor connector. Using ohmmeter, measure resistance between CMP sensor connector terminals. Resistance should be 835-1400 ohms (cold sensor) or 1060-1645 ohms (hot sensor).
2. Replace CMP sensor as necessary. If CMP sensor is okay, check for open or short circuit in wiring harness between ECM and CMP sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary.
3. If wiring harness is okay, remove and inspect CMP sensor. Also inspect camshaft timing pulley. Replace CMP sensor and/or camshaft timing pulley as necessary. If both components are okay, replace ECM.

1. Connect scan tool. see scheme 1 Start and warm engine to normal operating temperature. Operate vehicle at 38-50 MPH for 3 minutes or more. Stop vehicle and allow to idle for about 2 minutes. Turn ignition off.
2. Start engine and allow to idle. Operate vehicle at 38-50 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 DTC P0105, P0106 and P0401 are output simultaneously, perform DTC P0105 test first. If DTC P0401 and P0402 are output simultaneously, perform DTC P0402 test before performing DTC P0401 test.

Diagnosis & Repair (Using Toyota Scan Tool)

1. Check vacuum hoses. See appropriate illustration in VACUUM DIAGRAMS article. Repair vacuum hoses as necessary. If all hoses are okay, check VSV. Using scan tool, select ACTIVE TEST mode. Check operation of VSV when activated by scan tool. VSV is located under air intake manifold.
2. Start and run engine. With EGR system off, air should flow from small filter on end of VSV. (Scheme 75) With EGR system on, air should flow from port "G". If VSV operates as specified, go to step 6). If VSV does not operate as specified, go to next step.
3. Remove EGR VSV. Using ohmmeter, measure resistance between VSV terminals. Resistance should be 33-39 ohms at 68°F (20°C). Check for continuity between each terminal and body of VSV. If continuity exists, replace VSV. If continuity does not exist, go to next step.
4. Check VSV operation. Apply battery voltage to VSV terminals. Apply air pressure to port "E". Air should flow from small filter on end of VSV. (Scheme 75) Remove battery voltage from VSV terminals. Air should flow from port "G". Replace VSV as necessary. If VSV operates as specified, go to next step.
5. Check for open or short circuit in wiring harness between engine compartment fuse block and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary.
6. Perform EXHAUST GAS RECIRCULATION (EGR) SYSTEM TEST. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Repair as necessary. If no problem is indicated, check EGR vacuum modulator. See appropriate SYSTEM/COMPONENT TESTS article. Replace EGR vacuum modulator as necessary. If EGR vacuum modulator is okay, go to next step.
7. Check Manifold Absolute Pressure (MAP) sensor. See appropriate SYSTEM/COMPONENT TESTS article. Replace MAP sensor as necessary. If MAP sensor is okay, replace ECM.

Scheme 75

Diagnosis & Repair (Using OBD-II Scan Tool)

1. Check all EGR system vacuum hoses. Replace vacuum hoses as necessary. Access ECM behind glove box. If vehicle is not equipped with engine immobilizer system, go to step 3). If vehicle is equipped with engine immobilizer system, go to next step. NOTE: For information on engine immobilizer system, see COMPUTERIZED ENGINE CONTROLS in THEORY/OPERATION article.
2. On models with engine immobilizer system, disconnect ECM E8 connector. see scheme 3 Turn ignition on. Connect a jumper wire between ground and terminal No. 15 (Pink/Black wire) at ECM E8 connector. Go to step 4).
3. On models without engine immobilizer system, disconnect ECM E9 connector. see scheme 2 Turn ignition on. Connect a jumper wire between ground and terminal No. 23 (Pink/Black wire) at ECM E9 connector. Go to next step.
4. On all models, apply air pressure to VSV port "E". (Scheme 75) With jumper wire connected, VSV should be on. Air should flow from small filter on end of VSV. Disconnect jumper wire. Air should flow from port "G". If VSV operates as specified, go to step 8). If VSV does not operate as specified, go to next step.
5. Turn ignition off. Remove EGR VSV. VSV is located under air intake manifold. Using ohmmeter, measure resistance between valve terminals. Resistance should be 33-39 ohms at 68°F (20°C). Check for continuity between each terminal and body of VSV. If continuity exists, replace VSV. If continuity does not exist, go to next step.
6. Check VSV operation. Apply battery voltage to VSV terminals. Air should flow from small filter on end of VSV. Remove battery voltage from valve terminals. Air should flow from port "G". Replace VSV as necessary.
7. Check for open or short circuit in wiring harness between engine compartment fuse block and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary.
8. Perform EXHAUST GAS RECIRCULATION (EGR) SYSTEM TEST. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Repair as necessary. If no problem is indicated, check EGR vacuum modulator. See appropriate SYSTEM/COMPONENT TESTS article. Replace EGR vacuum modulator as necessary. If EGR vacuum modulator is okay, go to next step.
9. Check Manifold Absolute Pressure (MAP) sensor. See appropriate SYSTEM/COMPONENT TESTS article. Replace MAP sensor as necessary. If MAP sensor is okay, replace ECM.

1. Connect scan tool. see scheme 1 Start and warm engine to normal operating temperature. Operate vehicle at 38-50 MPH for 3 minutes or more. Stop vehicle and allow to idle for about 2 minutes. Turn ignition off.
2. Start engine and allow to idle. Operate vehicle at 38-50 MPH for 3 minutes or more. Stop vehicle and allow to idle for about 2 minutes.
3. 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.

1. Check all EGR system vacuum hoses. Replace hoses as necessary. If vacuum hoses are okay, check EGR valve. See appropriate SYSTEM/COMPONENT TESTS article. Replace EGR valve as necessary. If EGR valve is okay, go to next step.
2. Access ECM behind glove box. If vehicle is not equipped with engine immobilizer system, go to step 4). If vehicle is equipped with engine immobilizer system, go to next step. NOTE: For information on engine immobilizer system, see COMPUTERIZED ENGINE CONTROLS in THEORY/OPERATION article.
3. On models with engine immobilizer system, disconnect ECM E8 connector. see scheme 3 Turn ignition on. Connect a jumper wire between ground and terminal No. 15 (Pink/Black wire) at ECM E8 connector. Go to step 5).
4. On models without engine immobilizer system, disconnect ECM E9 connector. see scheme 2 Turn ignition on. Connect a jumper wire between ground and terminal No. 23 (Pink/Black wire) at ECM E9 connector. Go to next step.
5. On all models, apply air pressure to VSV port "E". (Scheme 75) With jumper wire connected, VSV should be on. Air should flow from small filter on end of VSV. (Scheme 75) Disconnect jumper wire. Air should flow from port "G". If VSV operates as specified, go to step 9). If VSV does not operate as specified, go to next step.
6. Turn ignition off. Remove EGR VSV. VSV is located underneath air intake manifold. Using ohmmeter, measure resistance between valve terminals. Resistance should be 33-39 ohms at 68°F (20°C). Check for continuity between each terminal and body of VSV. If continuity exists, replace VSV. If continuity does not exist, go to next step.
7. Check VSV operation. Apply battery voltage to VSV terminals. Air should flow from small filter on end of VSV. Remove battery voltage from valve terminals. Air should flow from port "G". Replace VSV as necessary. If VSV operates as specified, go to next step.
8. Check for open or short circuit in wiring harness between engine compartment fuse block and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary.
9. Perform EXHAUST GAS RECIRCULATION (EGR) SYSTEM TEST. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Repair as necessary. If no problem is indicated, check EGR vacuum modulator. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Replace EGR vacuum modulator as necessary. If EGR vacuum modulator is okay, go to next step.
10. Check Manifold Absolute Pressure (MAP) sensor. See appropriate SYSTEM/COMPONENT TESTS article. Replace MAP sensor as necessary. If MAP sensor is okay, replace ECM.

1. If any codes other than P0420 are displayed, diagnose and repair those codes first. If DTC P0420 is only displayed, check AFS circuits. See «DTC P1130»(ref-22531-S04980256592001010300000) : AIR/FUEL RATIO SENSOR CIRCUIT RANGE/PERFORMANCE (CALIF. EMISSIONS) test. Repair circuits as necessary. If AFS circuits are okay, go to next step.
2. Check oxygen sensor circuits. See «DTC P0136»(ref-22531-S14802810582001010300000) : HEATED OXYGEN SENSOR CIRCUIT (SENSOR NO. 2) test. Repair circuits as necessary. If oxygen sensor circuits and sensor are okay, replace catalytic converter.

1. If codes other than P0420 are present, diagnose and repair those codes first. If DTC P0420 is only displayed, check oxygen sensor No. 1. See «DTC P0130»(ref-22531-S08328140232001010300000) : OXYGEN SENSOR NO. 1 CIRCUIT (EXCEPT CALIF. EMISSIONS) test. Repair as necessary. If oxygen sensor circuits are okay, go to next step.
2. Check oxygen sensor No. 2 circuits. See «DTC P0136»(ref-22531-S14802810582001010300000) : HEATED OXYGEN SENSOR CIRCUIT (SENSOR NO. 2) test. Repair as necessary. If oxygen sensor circuits and sensor are okay, replace catalytic converter.

1. Check with vehicle driver if fuel tank cap was loose when refueling. If fuel tank cap was loose prior to refueling, it probably was cause of DTC to set. If fuel tank cap was not loose, check for cracks, deformations or loose connections in the following: Fuel tank. Charcoal canister. Fuel tank filler pipe. Hose and tubes around fuel tank and charcoal canister. Repair as necessary. If components are okay, go to next step.
2. Check if fuel tank cap is an original manufacturer's cap. If fuel tank cap is an original manufacturer's cap, go to next step. If fuel tank cap is not an original manufacturer's cap, replace cap with a manufacturer's cap.
3. Check if fuel cap is installed properly. Reinstall cap as necessary. If fuel cap is installed properly, go to next step.
4. Check for damaged fuel tank cap and gasket. Replace fuel cap as necessary. If fuel tank cap and gasket are okay, go to next step.
5. Remove fuel tank cap. Visually inspect fuel tank filler neck for damage. Replace filler neck as necessary. If filler neck is okay, go to next step.
6. Check vacuum hoses between vapor pressure sensor and VSV for vapor pressure sensor and between vapor pressure sensor and charcoal canister. Check hoses for correct installation, looseness and damage. Repair vacuum hoses as necessary. If vacuum hoses are okay, go to next step.
7. Check hose and tube between fuel tank and charcoal canister for correct installation and damage. Repair as necessary. If hose and tube are okay, go to next step.
8. Check charcoal canister. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. If canister is okay, go to next step.
9. Access ECM behind glove box. Turn ignition on. Backprobing ECM connector, measure voltage between terminals No. 1 (Yellow wire) and No. 9 (Brown wire) at ECM E8 connector. see scheme 2or see scheme 3. If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM.
10. On models with engine immobilizer system, go to next step. On models without engine immobilizer system, backprobe ECM connector and measure voltage between terminals No. 7 (Pink wire) and No. 9 (Brown wire) at ECM E8 connector. Disconnect vacuum hose from vapor pressure sensor. Sensor is mounted on top of charcoal canister, underneath rear of vehicle. Connect a vacuum pump to sensor. If voltage is 2.9-3.7 volts without vacuum applied and 1.3-2.1 volts with 1.18 in. Hg (4 kPa) applied, go to step 13). If voltage is not as specified, go to step 12).
11. On models with engine immobilizer system, backprobe ECM connector and measure voltage between terminals No. 8 (Pink wire) and No. 9 (Brown wire) at ECM E8 connector. Disconnect vacuum hose from vapor pressure sensor. Sensor is mounted on top of charcoal canister, underneath rear of vehicle. Connect a vacuum pump to sensor. If voltage is 2.9-3.7 volts without vacuum applied and 1.3-2.1 volts with 1.18 in. Hg (4 kPa) applied, go to step 13). If voltage is not as specified, go to next step.
12. On all models, check for an open or short in wiring harness between vapor pressure sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring is okay, replace vapor pressure sensor.
13. On all models, disconnect EVAP vacuum hose from charcoal canister. (Scheme 76) Ensure fuel tank cap is installed properly. Using compressed air, apply.58 psi (.04 kg/cm 2 ) to fuel tank. If tank does not hold pressure for a minimum of one minute, replace fuel tank, fuel filler pipe and/or fuel tank cap. If tank holds pressure, go to next step.
14. Check fuel tank overfill check valve. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Repair as necessary. If overfill check valve is okay, no fault is indicated at this time. Probable cause of DTC to set was an incorrectly installed fuel tank cap.

Scheme 76

1. Check EVAP VSV, vapor pressure sensor VSV and vapor pressure sensor wiring harness connectors for damaged pins, corrosion and loose wires. For component locations, see appropriate illustration in THEORY/OPERATION article. Repair connectors as necessary. If connectors are okay, 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. Repair vacuum hoses as necessary. If vacuum hoses are okay, go to next step.
3. Access ECM behind glove box. Turn ignition on. Backprobing ECM connector, measure voltage between terminals No. 1 (Yellow wire) and No. 9 (Brown wire) at ECM E8 connector. see scheme 2or see scheme 3. If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM. NOTE: For information on engine immobilizer system, see COMPUTERIZED ENGINE CONTROLS in THEORY/OPERATION article.
4. On models with engine immobilizer system, go to next step. On models without engine immobilizer system, backprobe ECM connector and measure voltage between terminals No. 7 (Pink wire) and No. 9 (Brown wire) at ECM E8 connector. Disconnect vacuum hose from vapor pressure sensor. Sensor is mounted on top of charcoal canister, underneath rear of vehicle. Connect a vacuum pump to sensor. If voltage is 2.9-3.7 volts without vacuum applied and 1.3-2.1 volts with 1.18 in. Hg (4 kPa) applied, go to step 7). If voltage is not as specified, go to step 6).
5. On models with engine immobilizer system, backprobe ECM connector and measure voltage between terminals No. 8 (Pink wire) and No. 9 (Brown wire) at ECM E8 connector. Disconnect vacuum hose from vapor pressure sensor. Sensor is mounted on top of charcoal canister, underneath rear of vehicle. Connect a vacuum pump to sensor. If voltage is 2.9-3.7 volts without vacuum applied and 1.3-2.1 volts with 1.18 in. Hg (4 kPa) applied, go to step 7). If voltage is not as specified, go to next step.
6. On all models, check for an open or short in wiring harness between vapor pressure sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring is okay, replace vapor pressure sensor.
7. Connect scan tool to DLC No. 3. Turn ignition on. Using scan tool, select ACTIVE TEST mode. Disconnect EVAP vacuum hose (for EVAP VSV) at charcoal canister. (Scheme 76) Start engine. Connect a vacuum gauge to disconnected vacuum hose. When EVAP VSV is activated by scan tool, vacuum should be present. When EVAP VSV is not activated, no vacuum should be present. If vacuum is as specified, go to step 11). If vacuum is not as specified, go to next step.
8. Check vacuum hose between intake manifold and EVAP VSV. Also, check vacuum hose between EVAP VSV and charcoal canister. Replace vacuum hoses as necessary. If vacuum hoses are okay, go to next step.
9. Check EVAP VSV. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Replace VSV as necessary. If VSV is okay, go to next step.
10. Check for an open or short in wiring harness between EFI main relay, EVAP VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring is okay, replace ECM.
11. Disconnect vacuum hoses from vapor pressure sensor VSV. VSV is mounted on top of charcoal canister, underneath rear of vehicle. Turn ignition on. Apply air pressure to VSV port "E". (Scheme 77) Using scan tool, select ACTIVE TEST mode. When vapor pressure sensor VSV is activated by scan tool, air should flow from port "F". When VSV is not activated, air should flow from port "G". If VSV operates as specified, go to step 14). If VSV does not operate as specified, go to next step.
12. Check vapor pressure sensor VSV. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Replace VSV as necessary. If VSV is okay, go to next step.
13. Check for open or short circuit in wiring harness between EFI main relay, vapor pressure sensor VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace ECM.
14. Disconnect vapor pressure sensor VSV connector. Start and run engine. Using scan tool, select ACTIVE TEST mode. On models with engine immobilizer, backprobe ECM connector and measure voltage between terminals No. 8 (Pink wire) and No. 9 (Brown wire) at ECM E8 connector. On models without engine immobilizer, backprobe ECM connector and measure voltage between terminals No. 7 (Pink wire) and No. 9 (Brown wire) at ECM E8 connector. see scheme 2or see scheme 3. On all models, with EVAP VSV activated, voltage should be 2 volts or less. If voltage is as specified, go to step 16). If voltage is not as specified, go to next step.
15. Check vacuum hose between charcoal canister and vapor pressure sensor VSV, and vacuum hose between vapor pressure sensor and vapor pressure sensor VSV. Repair vacuum hoses as necessary and retest. If vacuum hoses are okay, go to next step.
16. Remove fuel tank cap. Using scan tool, select ACTIVE TEST mode. Start engine. Using scan tool, switch EVAP VSV on. On models with engine immobilizer, backprobe ECM connector and measure voltage between terminals No. 8 (Pink wire) and No. 9 (Brown wire) at ECM E8 connector 5 seconds after switching EVAP VSV from on to off. On models without engine immobilizer, backprobe ECM connector and measure voltage between terminals No. 7 (Pink wire) and No. 9 (Brown wire) at ECM E8 connector 5 seconds after switching EVAP VSV from on to off. On all models, if voltage is 2.5 volts or less, replace charcoal canister. If voltage is more than 2.5 volts, go to next step.
17. Remove and inspect charcoal canister located underneath rear of vehicle. See appropriate SYSTEM/COMPONENT TESTS article. Replace charcoal canister as necessary. If charcoal canister is okay, go to next step.
18. Disconnect EVAP vacuum hose from charcoal canister. (Scheme 76) Ensure fuel tank cap is installed properly. Using compressed air, apply.58 psi (.04 kg/cm 2 ) to disconnected vacuum hose. If fuel tank does not hold pressure for a minimum of one minute, replace fuel tank, fuel filler pipe and/or fuel tank cap. If fuel tank holds pressure, go to next step.
19. Check fuel tank overfill check valve. See ON-BOARD REFILLING VAPOR RECOVERY (ORVR) SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Repair as necessary. If overfill check valve is okay, replace ECM.

Scheme 77

1. Check EVAP VSV, vapor pressure sensor VSV and vapor pressure sensor wiring harness connectors for damaged pins, corrosion and loose wires. For component locations, see THEORY/OPERATION article. Repair connectors as necessary. If connectors are okay, go to next step.
2. Check all EVAP related vacuum hoses for cracks, looseness and correct routing. For proper vacuum hose routing, see VACUUM DIAGRAMS article. Repair vacuum hoses as necessary. If vacuum hoses are okay, go to next step.
3. Access ECM behind glove box. Turn ignition on. Backprobing ECM connector, measure voltage between terminals No. 1 (Yellow wire) and No. 9 (Brown wire) at ECM E8 connector. see scheme 2or see scheme 3. If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM. NOTE: For information on engine immobilizer system, see COMPUTERIZED ENGINE CONTROLS in THEORY/OPERATION article.
4. On models with engine immobilizer system, go to next step. On models without engine immobilizer system, backprobe ECM connector and measure voltage between terminals No. 7 (Pink wire) and No. 9 (Brown wire) at ECM E8 connector. Disconnect vacuum hose from vapor pressure sensor. Sensor is mounted on top of charcoal canister, underneath rear of vehicle. Connect a vacuum pump to sensor. If voltage is 2.9-3.7 volts without vacuum applied and 1.3-2.1 volts with 1.18 in. Hg (4 kPa) applied, go to step 7). If voltage is not as specified, go to step 6).
5. On models with engine immobilizer system, backprobe ECM connector and measure voltage between terminals No. 8 (Pink wire) and No. 9 (Brown wire) at ECM E8 connector. Disconnect vacuum source hose from vapor pressure sensor. Sensor is mounted on top of charcoal canister, underneath rear of vehicle. Connect a vacuum pump to sensor. If voltage is 2.9-3.7 volts without vacuum applied and 1.3-2.1 volts with 1.18 in. Hg (4 kPa) applied, go to step 7). If voltage is not as specified, go to next step.
6. On all models, check for open or short circuit in wiring harness between vapor pressure sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace vapor pressure sensor.
7. On all models, disconnect EVAP VSV vacuum hoses. VSV is located underneath intake manifold. Apply air pressure to VSV port "E". (Scheme 78) Air should not flow from port "F". Access ECM behind glove box. Turn ignition on. On models with engine immobilizer system, connect a jumper wire between ground and terminal No. 3 (Violet/White wire) at ECM E9 connector. see scheme 3 On models without engine immobilizer system, connect a jumper wire between ground and terminal No. 22 (Violet/White wire) at ECM E9 connector. see scheme 2 On all models, air should flow from port "F". If VSV functions as specified, go to step 9). If VSV does not function as specified, go to next step.
8. Check EVAP VSV operation. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Replace VSV as necessary. If VSV is okay, go to step 10).
9. Check for open or short circuit in wiring harness between EFI main relay, EVAP VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace ECM.
10. Disconnect vapor pressure sensor VSV vacuum hoses. VSV is mounted on top of charcoal canister, underneath rear of vehicle. Apply air pressure to VSV port "E". (Scheme 77) Air should flow from port "G". Access ECM behind glove box. Turn ignition on. On models with engine Immobilizer system, connect a jumper wire between ground and terminal No. 16 (Violet wire) at ECM E8 connector. see scheme 3 On models without engine Immobilizer system, connect a jumper wire between ground and terminal No. 8 (Violet wire) at ECM E8 connector. see scheme 2 On all models, air should flow from port "F". If VSV does not function as specified, go to next step. If VSV functions as specified, check charcoal canister. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Replace charcoal canister as necessary. If charcoal canister is okay, go to step 13).
11. Check vapor pressure sensor VSV operation. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Replace VSV as necessary. If VSV is okay, go to next step.
12. Check for open or short circuit in wiring harness between EFI main relay, vapor pressure sensor VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring harness as necessary. If wiring harness is okay, replace ECM.
13. Disconnect EVAP hose from charcoal canister. (Scheme 75) Ensure fuel tank cap is installed properly. Using compressed air, apply.58 psi (.04 kg/cm 2 ) to disconnected EVAP hose. If fuel tank does not hold pressure for a minimum of one minute, replace fuel tank cap, fuel tank and/or fuel filler pipe. If fuel tank holds pressure, go to next step.
14. Check fuel tank overfill check valve. See ON-BOARD REFILLING VAPOR RECOVERY (ORVR) SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM/COMPONENT TESTS article. Repair as necessary. If overfill check valve is okay, replace ECM.

Scheme 78

1. Access ECM behind glove box. Turn ignition on. Backprobing ECM connector, measure voltage between terminals No. 1 (Yellow wire) and No. 9 (Brown wire) at ECM E8 connector. see scheme 2or see scheme 3. If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM. NOTE: For information on engine immobilizer system, see COMPUTERIZED ENGINE CONTROLS in THEORY/OPERATION article.
2. On models with engine immobilizer system, go to next step. On models without engine immobilizer system, backprobe ECM connector and measure voltage between terminals No. 7 (Pink wire) and No. 9 (Brown wire) at ECM E8 connector. Disconnect vacuum hose from vapor pressure sensor. Sensor is mounted on top of charcoal canister, underneath rear of vehicle. Connect a vacuum pump to sensor. If voltage is 2.9-3.7 volts without vacuum applied and 1.3-2.1 volts with 1.18 in. Hg (4 kPa) applied, replace ECM. If voltage is not as specified, go to next step.
3. On models with engine immobilizer system, backprobe ECM connector and measure voltage between terminals No. 8 (Pink wire) and No. 9 (Brown wire) at ECM E8 connector. Disconnect vacuum source hose from vapor pressure sensor. Sensor is mounted on top of charcoal canister, underneath rear of vehicle. Connect a vacuum pump to sensor. If voltage is 2.9-3.7 volts without vacuum applied and 1.3-2.1 volts with 1.18 in. Hg (4 kPa) applied, go to step 7). If voltage is not as specified, go to next step.
4. On all models, check for open or short circuit in wiring harness between vapor pressure sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring harness as necessary. If wiring harness is okay, replace vapor pressure sensor.

1. Test drive vehicle and check operation of speedometer. If speedometer is not functioning correctly, see INSTRUMENT PANEL article in ACCESSORIES/SAFETY EQUIPMENT section. If speedometer is functioning correctly, access ECM behind glove box. Ensure ignition is off. Shift gear selector to Neutral. Lift and support front of vehicle. Turn ignition on. NOTE: For information on engine immobilizer system, see COMPUTERIZED ENGINE CONTROLS in THEORY/OPERATION article.
2. On models without engine immobilizer system, backprobe ECM connector and measure voltage between measure voltage between ground and terminal No. 9 (Violet/White wire) at ECM E7 connector, while rotating front wheels. see scheme 2 On models with engine immobilizer system, backprobe ECM connector and measure voltage between ground and terminal No. 8 (Violet/White wire) at ECM E7 connector, while rotating front wheels. see scheme 3
3. On all models, as front wheels are rotated, voltage should pulse between zero and 5-6 volts. If voltage is as specified, replace ECM. If voltage is not as specified, check Violet/White wire between instrument cluster and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary.

Repair & Diagnosis

1. Ensure engine is at normal operating temperature and all accessories are off. Ensure A/C is off. Shift transaxle lever into Neutral position. Connect scan tool to DLC No. 3. Note engine RPM. Using a jumper wire, connect terminals TE1 and E1 at DLC No. 1 in engine compartment. (Scheme 79) 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. Ensure ignition is off. Access ECM behind glove box. Disconnect ECM E8 connector. see scheme 2or see scheme 3. Turn ignition on. On models without engine immobilizer system, measure voltage between ground and terminals No. 9 (Black/Orange wire) and No. 10 (White wire) at ECM E9 connector. On models with engine immobilizer system, measure voltage between ground and terminals No. 6 (Black/Orange wire) and No. 7 (White wire) at ECM E9 connector. On all models, If both readings are 9-14 volts, go to step 4). If any reading is not 9-14 volts, go to next step.
3. Turn ignition off. Disconnect IAC valve connector. IAC valve is located in front of throttle body at 6 o'clock position. Using ohmmeter, measure resistance between terminal No. 2 and terminals No. 1 and 3 at IAC valve. (Scheme 80) 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), check for an open or short in wiring harness between IAC valve and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary.
4. Check IAC valve operation. See IDLE CONTROL SYSTEM in appropriate SYSTEM/COMPONENT TESTS article. Replace IAC valve as necessary. If valve is okay, go to next step.
5. Remove IAC valve from throttle body. Check IAC valve for carbon build-up and blockage. Repair or replace IAC valve as necessary. If IAC valve is okay, replace ECM.
6. Check air induction system for leaks. Repair air induction system as necessary. If air induction system is okay, an open or short in A/C switch signal circuit may exist. Check A/C amplifier. See appropriate article in AIR CONDITIONING & HEATING section. Repair as necessary.

Scheme 79

Scheme 80

1. If using OBD-II scan tool, go to next step. If using Toyota scan tool, connect scan tool. see scheme 1 Switch scan tool to CHECK mode. Start and warm engine to normal operating temperature. Drive vehicle at 38-65 MPH with engine speed at 1600-3200 RPM for 3-5 minutes. If malfunction exists, MIL will illuminate.
2. If using OBD-II scan tool, start and warm engine to normal operating temperature. Drive vehicle at 38-65 MPH with engine speed at 1600-3200 RPM for 3-5 minutes. Stop vehicle and turn ignition off. Repeat driving part of test. If malfunction exists, MIL will illuminate.

1. If only DTC P1130 is displayed, go to next step. If other codes are displayed, diagnose and repair those codes first and retest system.
2. Disconnect AFS connector. AFS is located in exhaust manifold. Using ohmmeter, measure resistance between Black wire and Green wire at AFS connector. Resistance should be .8-1.4 ohms at 68°F (20°C). Replace AFS as necessary. If resistance is as specified, go to next step.
3. Reconnect AFS connector. Start engine and raise engine speed to 2500 RPM for 90 seconds. Using scan tool, monitor AFS output voltage. See «AIR/FUEL RATIO SENSOR SPECIFICATIONS»(ref-22531-S36372290932001010300000) table. If voltage is as specified, go to step 5). If voltage is not as specified, go to next step.
4. Check for open or short circuit in wiring harness between ECM and AFS. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace AFS.
5. Perform TEST DRIVE CONFIRMATION. If DTC P1130 resets, replace ECM. If DTC P1130 does not reset, no problem is indicated at this time.

1. If using OBD-II scan tool, go to next step. If using Toyota scan tool, connect scan tool. see scheme 1 Switch scan tool to CHECK mode. Start and warm engine to normal operating temperature. Drive vehicle at 38-65 MPH with engine speed at 1600-3200 RPM for 3-5 minutes. If malfunction exists, MIL will illuminate.
2. If using OBD-II scan tool, start and warm engine to normal operating temperature. Drive vehicle at 38-65 MPH with engine speed at 1600-3200 RPM for 3-5 minutes. Stop vehicle and turn ignition off. Repeat driving part of test. If malfunction exists, MIL will illuminate.

1. If only DTC P1133 is displayed, go to next step. If other codes are displayed, diagnose and repair those codes first and retest system.
2. Disconnect AFS connector. AFS is located in exhaust manifold. Using ohmmeter, measure resistance between Black/Yellow wire and Green wire at AFS connector. Resistance should be .8-1.4 ohms at 68°F (20°C). Replace AFS as necessary. If resistance is as specified, go to next step.
3. Perform TEST DRIVE CONFIRMATION. If DTC P1133 resets, replace AFS. If DTC P1133 does not reset, no problem is indicated at this time.

1. Access ECM behind glove box. Turn ignition on. Measure voltage between ground and terminal No. 2 (Black/Yellow Wire) at ECM connector E8. see scheme 2or see scheme 3. If voltage is 9-14 volts, replace ECM. If voltage is not 9-14 volts, go to next step.
2. Disconnect AFS connector. AFS is located in exhaust manifold. Using ohmmeter, measure resistance between Black/Yellow wire and Green wire at AFS connector. Resistance should be.8-1.4 ohms at 68°F (20°C). Replace AFS as necessary. If resistance is as specified, check for open or short circuit in wiring harness between EFI main relay, AFS and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary.

1. Check for spark at misfiring cylinder. See IGNITION CHECKS in appropriate BASIC TESTING article. If spark is present, go to next step. If spark is not present, go to step 4).
2. Check for open or short in IGF circuit between ECM and ignition coil. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary. If circuit is okay, go to next step.
3. Disconnect ignition coil No. 1 connector. Coil is located under throttle body. Access ECM behind glove box. Turn ignition on. On models without engine immobilizer system, backprobe ECM connector and measure voltage between ground and terminal No. 3 (White/Red wire) at ECM E9 connector. see scheme 2 On models with engine immobilizer system, backprobe ECM connector and measure voltage between ground and terminal No. 17 (White/Red wire) at ECM E9 connector. see scheme 3 On all models, if voltage is 4.5-5.5 volts, replace ignition coil. If voltage is not 4.5-5.5 volts, replace ECM. NOTE: For information on engine immobilizer system, see COMPUTERIZED ENGINE CONTROLS in THEORY/OPERATION article.
4. Check for open or short in IGT1 circuit (Black wire) between ECM E9 connector and ignition coil No. 1. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary. If circuit is okay, go to next step.
5. Access ECM behind glove box. On models without engine immobilizer system, backprobe ECM connector and measure voltage between ground and terminal No. 20 (Black wire) at ECM E9 connector while cranking engine. On models with engine immobilizer system, backprobe ECM connector and measure voltage between ground and terminal No. 23 (Black wire) at ECM E9 connector while cranking engine. On all models, 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 No. 1 connector. On models without engine immobilizer system, backprobe ECM connector and measure voltage between ground and terminal No. 20 (Black wire) at ECM E9 connector while cranking engine. On models with engine immobilizer system, backprobe ECM connector and measure voltage between ground and terminal No. 23 (Black wire) at ECM E9 connector while cranking engine. On all models, 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 wiring harness connector. If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, repair ignition coil No. 1 power source circuit. See appropriate wiring diagram in WIRING DIAGRAMS article.
8. Check for open or short circuit in wiring harness between ignition switch and ignition coil No. 1. Repair wiring harness as necessary. If wiring harness is okay, check EFI relay. See appropriate SYSTEM/COMPONENT TESTS article. Replace relay as necessary. If relay is okay, replace coil No. 1.

1. Check for spark at misfiring cylinder. See IGNITION CHECKS in appropriate BASIC TESTING article. If spark is present, go to next step. If spark is not present, go to step 4).
2. Check for open or short in IGF circuit between ECM and ignition coil. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary. If circuit is okay, go to next step.
3. Disconnect ignition coil No. 2 connector. Coil is located under throttle body. Access ECM behind glove box. Turn ignition on. On models without engine immobilizer system, backprobe ECM connector and measure voltage between ground and terminal No. 3 (White/Red wire) at ECM E9 connector. see scheme 2 On models with engine immobilizer system, backprobe ECM connector and measure voltage between ground and terminal No. 17 (White/Red wire) at ECM E9 connector. see scheme 3 On all models, if voltage is 4.5-5.5 volts, replace ignition coil. If voltage is not 4.5-5.5 volts, replace ECM. NOTE: For information on engine Immobilizer system, see COMPUTERIZED ENGINE CONTROLS in THEORY/OPERATION article.
4. Check for open or short in IGT2 circuit (Yellow/Red wire) between ECM E9 connector and ignition coil No. 2. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary. If circuit is okay, go to next step.
5. Access ECM behind glove box. On models without engine immobilizer system, backprobe ECM connector and measure voltage between ground and terminal No. 19 (Yellow/Red wire) at ECM E9 connector while cranking engine. On models with engine immobilizer system, backprobe ECM connector and measure voltage between ground and terminal No. 22 (Yellow/Red wire) at ECM E9 connector while cranking engine. On all models, 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 No. 2 connector. On models without engine immobilizer system, backprobe ECM connector and measure voltage between ground and terminal No. 19 (Yellow/Red wire) at ECM E9 connector while cranking engine. On models with engine immobilizer system, backprobe ECM connector and measure voltage between ground and terminal No. 22 (Yellow/Red wire) at ECM E9 connector while cranking engine. On all models, 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. 2 (Black/Red wire) at ignition coil wiring harness connector. If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, repair ignition coil No. 2 power source circuit. See appropriate wiring diagram in WIRING DIAGRAMS article.
8. Check for open or short circuit in wiring harness between ignition switch and ignition coil No. 2. Repair wiring harness as necessary. If wiring harness is okay, check EFI relay. See appropriate SYSTEM/COMPONENT TESTS article. Replace relay as necessary. If relay is okay, replace coil No. 2.

1. Check stoplights. If stoplights do not function properly, repair as necessary and retest system. If stoplights function properly, go to next step.
2. Access ECM behind glove box. Turn ignition on. On models without engine immobilizer system, backprobe ECM connector and measure voltage between ground and terminal No. 4 (Green/White wire) at ECM E7 connector. see scheme 2 On models with engine immobilizer system, backprobe ECM connector and measure voltage between ground and terminal No. 9 (Green/White wire) at ECM E7 connector. see scheme 3 On all models, with brake pedal depressed voltage should be 7.5-14.0 volts. With brake pedal released, voltage should be less than 1.5 volts. If voltage is not as specified, go to next step. If voltage is as specified, check wiring harness and connectors. Problem is intermittent.
3. Check for short in wiring harness between ECM and stoplight switch. Repair wiring as necessary. If wiring harness is okay, replace ECM. Retest system.

1. Turn ignition off. Access ECM behind glove box. On models without engine immobilizer system, backprobe ECM connector and measure voltage between ground and terminal No. 1 (Black/Yellow wire) at ECM E7 connector. see scheme 2 On models with engine immobilizer system, backprobe ECM connector and measure voltage between ground and terminal No. 2 (Black/Yellow wire) at ECM E7 connector. see scheme 3 On all models, 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. EFI fuse is located in engine compartment fuse box. Replace fuse as necessary. If fuse is okay, check circuit between EFI fuse and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary.

1. Access ECM behind glove box. Turn ignition on. Backprobing ECM connector, measure voltage between ground and specified terminal at ECM E7 connector. See appropriate table: «PARK/NEUTRAL POSITION SWITCH VOLTAGE (WITHOUT ENGINE»(ref-22531-S30899022212001010300000) IMMOBILIZER SYSTEM) TABLE «PARK/NEUTRAL POSITION SWITCH VOLTAGE (WITH ENGINE IMMOBILIZER»(ref-22531-S04610242922001010300000) SYSTEM) see scheme 2or see scheme 3. 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 (WITHOUT ENGINE IMMOBILIZER) Shifter Position (1) Terminal No. Volts Park & Neutral 17 Zero " 18 Zero " 19 Zero " 22 Zero Reverse 17 9-14 " 18 Zero " 19 Zero " 22 9-14 Drive 17 Zero " 18 Zero " 19 Zero " 22 9-14 2 17 Zero " 18 9-14 " 19 Zero " 22 9-14 Low 17 Zero " 18 Zero " 19 9-14 " 22 9-14 (1) Measure voltage between ground and terminal listed at ECM E7 connector. see scheme 2 PARK/NEUTRAL POSITION SWITCH VOLTAGE (WITH ENGINE IMMOBILIZER) Shifter Position (1) Terminal No. Volts Park & Neutral 17 Zero " 16 Zero " 15 Zero " 22 Zero Reverse 17 9-14 " 16 Zero " 15 Zero " 22 9-14 Drive 17 Zero " 16 Zero " 15 Zero " 22 9-14 2 17 Zero " 16 9-14 " 15 Zero " 22 9-14 Low 17 Zero " 16 Zero " 15 9-14 " 22 9-14 (1) Measure voltage between ground and terminal listed at ECM E7 connector. see scheme 3
2. Disconnect PNP switch connector. Using ohmmeter, check continuity of switch terminals in specified positions. See «PARK/NEUTRAL POSITION SWITCH CONTINUITY»(ref-22531-S40613073342001010300000) table. (Scheme 81) Replace switch as necessary. If switch is okay, check wiring harness between battery and PNP switch and between PNP switch and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace ECM.

PARK/NEUTRAL POSITION SWITCH CONTINUITY

Scheme 81