Engine Control System Tests W/codes: Diagnosis Toyota Tercel L50 рестайлинг

DIAGNOSTIC TROUBLE CODE DEFINITIONS

DIAGNOSTIC TROUBLE CODE (DTC) DEFINITIONS

Diagnosis & Repair

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

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 (Light Blue wire) and No. 9 (Brown wire) at ECM E6 connector. see scheme 2
4. If temperature displayed on scan tool is 284°F (140°C) or more, check for open circuit in wiring harness between IAT sensor 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 E6 connector. see scheme 2 Turn ignition on. If temperature displayed is -40°F (-40°C), locate and repair short circuit in wiring harness between IAT 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.

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 (Black/Red wire) and No. 9 (Brown wire) at ECM E6 connector. see scheme 2
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 E6 connector. see scheme 2 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 or 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. 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 within specification, check all connections. Problem may be intermittent.
3. If percentages are not within specification, turn ignition off. Disconnect TP sensor connector. Turn ignition on. Using DVOM, measure voltage between ground and terminal No. 1 (Light Green/Red 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. 10 (Yellow/Green wire) at ECM E6 connector. see scheme 2 Voltage should be.3-1.0 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 open or short 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. 9 (Brown wire) and No. 11 (Light Green/Red wire) at ECM E6 connector. see scheme 2 If voltage is 4.5-5.5 volts, check wiring harness for open in Light Green/Red 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 sensor No. 1. Snap accelerate engine 3 times to about 4000 RPM. Sensors 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, check for open or short circuit in wiring harness between ECM and suspect sensor. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, go to next step.
3. Check exhaust system for leaks. Repair as necessary. If exhaust system 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 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 vehicle 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 «DTC P0171 OR P0172»(ref-22542-S01729705602001010300000): SYSTEM TOO LEAN/RICH test.
3. If scan tool indicates other than reading in step 2), operate engine at 2500 RPM for 90 seconds. Monitor oxygen sensor voltage. If voltage constantly fluctuates from less than.4 volt to more than.6 volt, 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. If any 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 sensor.

1. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM connector. Measure voltage between ground and terminal No. 21 (White/Red wire) at ECM E7 connector. see scheme 2 If voltage is 9-14 volts, replace ECM. If voltage is not 9-14 volts, go to next step.
2. Turn ignition off. Disconnect oxygen sensor connector. Connector is located under right side of shifter console (near shifter). To access connector, it may be necessary to remove passenger seat. Using an ohmmeter, measure resistance between sensor connector terminals No. 1 (White/Red wire) and No. 2 (Black/Red wire).
3. If resistance is 11-16 ohms at 68°F (20°C), check wiring harness between main relay, heated oxygen sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If resistance is not 11-16 ohms, replace sensor.

1. If DTC P0172 is present, go to next step. If DTC P0171 is present, check with customer if vehicle ran out of fuel. If vehicle did not run out of fuel, go to next step. If vehicle ran out of fuel, running out of fuel was probable cause for DTC to set. Clear DTCs and retest.
2. 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 output voltage and short-term fuel trim.
3. 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-22542-S40761021652001010300000): OXYGEN SENSOR CIRCUIT (SENSOR NO. 1) test.
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 all 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, go to next step.
6. Check exhaust system for leaks. Repair exhaust system as necessary. If exhaust 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. Connect Toyota or OBD-II scan tool. see scheme 1 Record any DTCs and freeze frame data. Switch scan tool to CHECK mode (Toyota scan tool 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-22542-S05663866862001010300000) table. If using OBD-II scan tool, turn ignition off after symptom is simulated the first time, then repeat test drive again. 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

1. Check vacuum hoses for leaks, blockage and proper routing. Also, check wiring harness and wiring harness connectors for damage or poor connections. Repair as necessary and perform TEST DRIVE CONFIRMATION. If vacuum hoses and wiring harness connectors are okay, go to next step.
2. 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.
3. Access ECM behind glove box. Turn ignition on. Using DVOM, backprobe ECM connector. Measure voltage between ground and injector terminals at ECM E7 connector. See «IDENTIFYING INJECTOR TERMINALS»(ref-22542-S29159202182001010300000) table. see scheme 2 If voltage is 9-14 volts for each circuit, go to step 5). If voltage is not 9-14 volts, go to next step. IDENTIFYING INJECTOR TERMINALS Injector No. (1) Terminal No. Wire Color 1 12 Green 2 25 Yellow 3 11 Red 4 24 Blue (1) Terminals are located in ECM E7 connector.
4. 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.
5. 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.
6. If all injectors are 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 E6 connector. see scheme 2 Backprobing ECM connector, measure resistance between ground and terminal No. 14 (Black wire) at ECM E6 connector. If resistance is infinity, go to step 3). If resistance is not infinity, go to next step.
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 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.
4. Clear DTCs. Start and warm engine to normal operating temperature. 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 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).
2. Replace CKP sensor as necessary. If CKP sensor is okay, 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.
3. If wiring harness is okay, 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.

1. Disconnect CMP sensor connector. Using ohmmeter, measure resistance between CMP sensor connector terminals. Resistance should be 985-1600 ohms (cold sensor) or 1265-1890 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 signal plate. Replace CMP sensor and/or signal plate as necessary. If both components are okay, replace ECM.

1. Connect scan tool. see scheme 1 Start and warm engine to normal operating temperature. Drive vehicle at 31-40 MPH for 5-10 minutes. Stop vehicle. Retrieve codes. See SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.
2. If codes other than P0420 are present, diagnose and repair those codes first. If only DTC P0420 is displayed, check sensor No. 1 circuits. See «DTC P0130»(ref-22542-S40761021652001010300000): HEATED OXYGEN SENSOR FAULT (SENSOR NO. 1) test. Repair wiring as necessary. If oxygen circuits are okay, go to next step.
3. Check sensor No. 2 circuits. See «DTC P0136»(ref-22542-S08853831622001010300000): HEATED OXYGEN SENSOR CIRCUIT (SENSOR NO. 2) test. Repair wiring as necessary. If oxygen circuits 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. Replace 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 for cracks or damage. See appropriate SYSTEM/COMPONENT TESTS article. Replace canister as necessary. 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. 9 (Brown wire) and No. 11 (Light Green/Red wire) at ECM E6 connector. see scheme 2 If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM.
10. Backprobe ECM connector. Measure voltage between terminals No. 12 (Yellow/Black wire) and No. 9 (Brown wire) at ECM E6 connector. Disconnect vacuum hose from vapor pressure sensor. Sensor is located in right rear of engine compartment. Connect a vacuum pump to sensor. If voltage is 3.0-3.6 volts without vacuum applied and 1.3-2.1 volts with.59 in. Hg (2 kPa) applied, go to step 12). If voltage is not as specified, go to next step.
11. 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.
12. Disconnect charcoal canister-to-fuel tank vacuum hose. (Scheme 40) Ensure fuel tank cap is installed properly. Using compressed air, apply.71 psi (.05 kg/cm 2 ) to disconnected vacuum hose. If tank does not hold pressure for a minimum of one minute, replace fuel tank. If tank holds pressure, no fault is indicated at this time. Probable cause of DTC to set was an incorrectly installed fuel tank cap.

Scheme 40

Diagnosis & Repair (Using OBD-II Scan Tool)

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. Replace 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. 11 (Light Green/Red wire) and No. 9 (Brown wire) at ECM E6 connector. see scheme 2 If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM.
4. Backprobe ECM connector. Measure voltage between terminals No. 12 (Yellow/Black wire) and No. 9 (Brown wire) at ECM E6 connector. Disconnect vacuum hose from vapor pressure sensor. Sensor is located in right rear of engine compartment. Connect a vacuum pump to sensor. If voltage is 3.0-3.6 volts without vacuum applied and 1.3-2.1 volts with.59 in. Hg (2 kPa) applied, go to step 6). If voltage is not as specified, go to next step.
5. 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.
6. Access ECM behind glove box. Turn ignition on. Connect a jumper wire between ground and terminal No. 7 (Blue/White wire) at ECM E6 connector. With jumper wire connected EVAP Vacuum Switching Valve (VSV) is on. Apply air pressure to VSV port "E". Air from port "E" should flow from port "F". see scheme 5 Disconnect jumper wire. Air from port "E" should not flow from port "F". If VSV operates as specified, go to step 10). If VSV does not operate as specified, go to next step.
7. Remove EVAP VSV. Using ohmmeter, measure resistance between valve terminals. Resistance should be 27-33 ohms at 68°F (20°C). Measure resistance between each terminal and body of VSV. Resistance should be infinite. If resistance is not as specified, replace VSV. If resistance is as specified, go to next step.
8. Check VSV operation. Apply battery voltage to VSV terminals. Apply air pressure to VSV port "E". see scheme 5 Air from port "E" should flow from port "F". Remove battery voltage from VSV terminals. Air from port "E" should not flow from port "F". Replace VSV as necessary. If VSV operates as specified, go to next step.
9. Check for open or short circuit in wiring harness between EVAP VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace ECM.
10. Access ECM behind glove box. Turn ignition on. Connect a jumper wire between ground and terminal No. 8 (Gray/Yellow wire) at ECM E6 connector. With jumper wire connected vapor pressure sensor Vacuum Switching Valve (VSV) is on. Apply air pressure to VSV port "E". see scheme 6 Air from port "E" should flow from port "F". Disconnect jumper wire. Air from port "E" should flow from port "G". If VSV operates as specified, check charcoal canister. See appropriate SYSTEM/COMPONENT TESTS article. If VSV does not operate as specified, go to next step.
11. Disconnect vapor pressure sensor VSV vacuum hoses. VSV is mounted near right shock tower. Using ohmmeter, measure resistance between VSV terminals. If resistance is 37-44 ohms at 68°F (20°C), go to next step. If resistance is not 37-44 ohms, replace VSV.
12. Check for continuity between each VSV terminal and VSV body. If continuity exists, replace VSV. If continuity does not exist, apply air pressure to VSV port "E". see scheme 6 Air from port "E" should flow from port "G". Apply battery voltage to VSV terminals. Air from port "E" should flow from port "F". If VSV operates as specified, go to next step. If VSV does not operate as specified, replace VSV.
13. Check for open or short 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.

1. Access ECM behind glove box. Turn ignition on. Backprobing ECM connector, measure voltage between terminals No. 11 (Light Green/Red wire) and No. 9 (Brown wire) at ECM E6 connector. see scheme 2 If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, replace ECM.
2. Backprobe ECM connector. Measure voltage between terminals No. 12 (Yellow/Black wire) and No. 9 (Brown wire) at ECM E6 connector. Disconnect vacuum hose from vapor pressure sensor. Sensor is located in right rear of engine compartment. Connect a vacuum pump to sensor. If voltage is 3.0-3.6 volts without vacuum applied and 1.3-2.1 volts with.59 in. Hg (2 kPa) vacuum applied, replace ECM. If voltage is not as specified, go to next step.
3. 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.

1. Test drive vehicle and check operation of speedometer. If speedometer is not functioning correctly, see appropriate INSTRUMENT PANEL article under ACCESSORIES/SAFETY EQUIPMENT section. If speedometer is functioning correctly, go to next step.
2. Access ECM behind glove box. Ensure ignition is off. Ensure shift lever is in Neutral. Lift and support front of vehicle. Turn ignition on.
3. Using DVOM, backprobe ECM connector. Measure voltage between ground and terminal No. 11 (Yellow wire) at ECM E8 connector while slowly rotating front wheel. see scheme 2 DVOM should indicate a pulse voltage from zero to 4.5-5.5 volts.
4. If voltage is as specified, replace ECM. If voltage is not as specified, check for open circuit in wiring harness between instrument cluster and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary.

Repair & Diagnosis (Using Toyota Scan Tool)

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. see scheme 1 Note engine RPM. Using scan tool, select ACTIVE TEST mode. With TE1 switched on, note engine RPM and compare with first RPM reading. If difference in engine speed is more than 100 RPM, go to step 8). If difference in engine speed is 100 RPM or less, turn ignition off and go to next step.
2. Turn ignition on. Using scan tool, check IAC duty signal ratio. If IAC duty ratio is 27-47 percent, go to next step. If IAC duty ratio is not 27-47 percent, replace ECM.
3. Check IAC valve operation. See appropriate SYSTEM/COMPONENT TESTS article. If IAC valve operation is not as specified, go to step 5). If IAC valve is okay, go to next step.
4. Remove IAC valve from throttle body. Check IAC valve and throttle body for carbon build-up and blockage. Repair or replace IAC valve and throttle body as necessary. If IAC valve is okay, go to step 8).
5. Disconnect IAC valve connector. Turn ignition on. Measure voltage between ground and Black/Red wire at IAC valve wiring harness connector. If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, check for open or short circuit in Black/Red wire. Repair wiring as necessary.
6. Check for an open or short circuit in Brown wire between IAC valve and ground. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring is okay, go to next step.
7. Check for an open or short circuit in Blue wire between IAC valve and terminal No. 10 at ECM E6 connector. see scheme 2 Repair wiring as necessary. If wiring is okay, replace IAC valve.
8. 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 & HEAT section. Repair as necessary.

Repair & Diagnosis (Using OBD-II Scan Tool)

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. see scheme 1 Note engine RPM. Using a jumper wire, connect terminals TE1 and E1 at DLC No. 1 in engine compartment. (Scheme 41) Note engine RPM and compare with first RPM reading. If difference in engine speed is more than 100 RPM, go to step 9). If difference in engine speed is 100 RPM or less, go to next step.
2. Connect oscilloscope between ground and terminal No. 10 (Blue wire) at ECM E7 connector. see scheme 2 Start engine. Ensure engine is at normal operating temperature. Oscilloscope should display a square wave pattern that toggles from about 4.5 volts at 4 milliseconds to about 0.5 volt at 2 milliseconds. If IAC duty signal output is okay, go to step 6). If IAC duty signal output is not okay, turn ignition off and go to next step.
3. Turn ignition on. Measure voltage between ground and terminal No. 10 (Blue wire) at ECM E7 connector. If voltage is 9-14 volts, replace ECM. If voltage is not 9-14 volts, go to next step.
4. Disconnect IAC valve connector. Turn ignition on. Measure voltage between ground and Black/Red wire at IAC valve wiring harness connector. If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, check for open or short circuit in Black/Red wire. Repair wiring as necessary.
5. Check for an open or short circuit in Blue wire between IAC valve and terminal No. 10 at ECM E7 connector. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring is okay, replace IAC valve.
6. Check IAC valve operation. See appropriate SYSTEM/COMPONENT TESTS article. If IAC valve operation is not as specified, go to step 8). If IAC valve operation is okay, go to next step.
7. Check for an open or short circuit in Brown wire between IAC valve and ground. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring is okay, replace IAC valve.
8. Remove IAC valve from throttle body. Check IAC valve and throttle body for carbon build-up and blockage. Repair or replace IAC valve and throttle body as necessary. If IAC valve is okay, go to next step.
9. 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/HEAT section. Repair as necessary.

Scheme 41

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 (Red/Blue wire) between ECM and ignitor. Ignitor is located near brake master cylinder. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If circuit is okay, go to next step.
3. Disconnect 8-pin ignitor connector. Access ECM behind glove box. Turn ignition on. Measure voltage between ground and terminal No. 7 (Red/Blue wire) at ECM E7 connector. see scheme 2 If voltage is 4.5-5.5 volts, replace ignitor. If voltage is not 4.5-5.5 volts, replace ECM.
4. Check for open or short in IGT1 circuit (Green wire) and IGT2 circuit (Blue/Yellow wire) between ECM and ignitor. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If circuits are okay, go to next step.
5. Access ECM behind glove box. Locate ECM E7 connector. see scheme 2 Backprobing ECM connector, measure voltage between ground and terminals No. 1 (Green wire) and No. 14 (Blue/Yellow wire) at ECM E7 connector while cranking engine. If both readings are.1-4.5 volts, go to next step. If any reading is not.1-4.5 volts, replace ECM.
6. Disconnect 8-pin ignitor connector. Backprobing ECM connector, measure voltage between ground and terminals No. 1 (Green wire) and No. 14 (Blue/Yellow wire) at ECM E7 connector while cranking engine. If both readings are.1-4.5 volts, go to next step. If any reading is not.1-4.5 volts, replace ECM.
7. Turn ignition on. Measure voltage between ground and terminal No. 7 (Black/White wire) at ignitor wiring harness connector. (Scheme 42) If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, check and repair ignitor 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, and between ignition coil and ignitor. Repair wiring as necessary. If wiring harness is okay, go to next step.
9. Check ignition coil. See IGNITION CHECKS in appropriate BASIC TESTING article. Replace coil as necessary. If coil is okay, go to next step.
10. Check EFI main relay. See appropriate SYSTEM/COMPONENT TESTS article. Replace relay as necessary. If relay is okay, replace ignitor.

Scheme 42

1. Turn ignition off. Access ECM behind glove box. Using DVOM, measure voltage between ground and terminal No. 2 (White/Red wire) at ECM E8 connector. see scheme 2 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 fuse box on right side of engine compartment. If fuse is blown, check and repair cause of fuse to blow. Replace fuse. If fuse is okay, check circuit between EFI fuse and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary.

1. Disconnect PNP switch connector. PNP switch is located at transaxle where shifter select cable is mounted. Using ohmmeter, check continuity of switch terminals in specified positions. (Scheme 43)and (Scheme 44). Replace switch as necessary.
2. If switch is okay, access ECM behind glove box. Turn ignition on. Using DVOM, measure voltage between ground and terminal No. 15 (Black wire) at ECM E7 connector. see scheme 2
3. Voltage should be 0-3 volts in "P" or "N" position. Voltage should be 9-14 volts in any other shift selector position. If voltage is as specified, replace ECM.
4. If any voltage is not as specified, check for open or short circuit in wiring harness between PNP switch and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary.

Scheme 43

Scheme 44