Engine Control System Self Diagnostics: Other Toyota MR2 W30

TWO-TRIP DETECTION LOGIC

When a malfunction initially occurs, Diagnostic Trouble Code (DTC) will be temporarily stored in ECM memory but Malfunction Indicator Light (MIL) will not illuminate. The second time malfunction is detected, MIL will illuminate provided ignition is turned off and then back on after first malfunction was detected. This is referred to as "Two-Trip Detection Logic" and only applies to specific DTCs. When road testing vehicle in CHECK mode using Toyota hand-held tester, two-trip detection logic will not function and MIL will illuminate the first time a malfunction is detected.

DATA LINK CONNECTOR

OBD-II regulations (SAE J-1962) standardizes configuration of Data Link Connector No. 3 (DLC3). DLC3 is located under driver's side of instrument panel, left of steering column. (Scheme 208)

Scheme 208

FREEZE FRAME DATA

Engine Control Module (ECM) records engine operating conditions when a misfire or fuel trim (mixture) malfunction or when various other malfunctions exist. ECM records engine operating conditions for the fuel system, calculated load, engine coolant temperature, engine speed, vehicle speed, etc. when a malfunction exists. This information is referred to as freeze frame data. If more than one Diagnostic Trouble Code (DTC) exists, only freeze frame data for the first DTC is recorded. Freeze frame data is useful for determining conditions when a malfunction occurred. OBD-II scan tool or Toyota hand-held tester may by used to read freeze frame data.

EVAP Monitor & Drive Cycle Pattern

For EVAP monitor and drive cycle pattern (Scheme 209)and (Scheme 210).

Scheme 209

Scheme 210

Heated Oxygen Sensor Monitor & Drive Cycle Pattern

For heated oxygen sensor monitor and drive cycle pattern (Scheme 211)

Scheme 211

Oxygen Sensor Heater & A/F Sensor Heater Monitor & Drive Cycle Pattern

For oxygen sensor heater and A/F sensor heater monitor and drive cycle pattern (Scheme 212)

Scheme 212

Catalyst Monitor & Drive Cycle Pattern

For catalyst monitor and drive cycle pattern (Scheme 213)

Scheme 213

ENGINE CONTROL MODULE PROGRAMMING

An engine immobilizer system may be used. On models equipped with engine immobilizer system, if Engine Control Module (ECM) is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. Models equipped with engine immobilizer system may be identified by looking at the ignition key. On models equipped with engine immobilizer system, the top of the ignition key is thicker than a standard ignition key, as a transponder chip is incorporated into the top of the ignition key. For programming procedures, see COMPUTER RELEARN PROCEDURES - TOYOTA article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.

SUMMARY

If no Diagnostic Trouble Codes (DTC) are present and a no start condition exists, proceed to BASIC DIAGNOSTIC PROCEDURES - 4-CYL article. If no DTCs are present and a driveability condition exists, proceed to TROUBLESHOOTING - NO CODES article for diagnosis by symptom (i.e., ROUGH IDLE, ENGINE STALLS, etc.).

Possible Causes

DTC P0010 is set if ECM detects an open or short in VVT OCV circuit. Possible causes are

1. VVT OCV circuit is open or shorted.
2. Defective VVT OCV.
3. Defective ECM.

DTC is set if ECM detects valve timing remains fixed and does not change when engine is at normal operating temperature and engine speed is 400-4000 RPM. Possible causes are

1. Incorrect valve timing.
2. Defective VVT OCV.
3. Defective VVT controller.
4. Defective ECM.

DTC will set when a deviation in crankshaft position sensor signal and VVT sensor signal is detected (2 trip detection logic). Possible causes are

1. Mechanical system malfunction; (jumping teeth of timing chain, chain stretched).
2. Defective ECM.

For DTC detection conditions and possible causes (Scheme 214)

Scheme 214

DTC is set when ECM detects an open or short in MAF meter circuit for more than 3 seconds with engine speed at 4000 RPM or less. ECM will operate in fail-safe mode if DTC P0100 is set. Possible causes are

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

This DTC uses two-trip detection logic. DTC is set when ECM detects MAF meter output is greater than 2.2 volts with throttle valve closed with engine speed of 900 RPM or less, or MAF meter output is less than 1.06 volts with Throttle Position (TP) sensor VTA circuit signal voltage of 0.63 volt or more with engine speed of 1500 RPM or more. Possible cause is defective MAF meter.

DTC is set when ECM detects an open or short in ECT sensor circuit. If DTC P0115 exists, ECM will operate in fail-safe mode in which engine coolant temperature is assumed to be 176°F (80°C). Possible causes are

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

DTC is set after vehicle speed has exceeded 19 MPH once and TP sensor output voltage is out of range while vehicle speed is 0-19 MPH. Possible cause is defective TP sensor.

DTC is set when heated oxygen sensor 1 voltage remains at 0.4 volt or more, or 0.55 volt or less during idle, once engine is at normal operating temperature. Possible causes are

1. Heated oxygen sensor 1 circuit is open or shorted.
2. Defective heated oxygen sensor 1.
3. Air induction malfunction.
4. Improper fuel pressure.
5. Defective fuel injector.
6. Defective ECM.

DTC is set when ECM detects a response time of one second or more from heated oxygen sensor to change from rich to lean, or lean to rich when engine is warm and idling. Possible causes are

1. Heated oxygen sensor 1 circuit is open or shorted.
2. Defective heated oxygen sensor 1.
3. Air induction malfunction.
4. Improper fuel pressure.
5. Defective fuel injector.
6. Vehicle has run out of fuel.
7. Defective ECM.

These DTCs use two-trip detection logic. For DTC detection conditions and possible causes (Scheme 215)

Scheme 215

DTC is set when heated oxygen sensor 2 voltage remains at 0.4 volt or more, or 0.5 volt or less during vehicle operation (25 MPH or more), once engine is at normal operating temperature. Possible cause is

1. Heated oxygen sensor 2 circuit is open or shorted.
2. Defective heated oxygen sensor 2.

For DTC detection conditions and possible causes (Scheme 216)

Scheme 216

Note. For any particular 200 revolutions of engine, misfiring which could result in overheating of catalyst is detected. This will cause MIL to blink (1 trip detection logic).

Note. For any particular 1000 revolutions of engine, misfiring which could result in a deterioration of emissions. This will cause MIL to light up (2 trip detection logic).

Note. When 2 or more DTCs for misfiring cylinder are recorded repeatedly and DTC P0300 does not exist, it indicates misfires were detected and recorded at different times. If misfire cannot be reproduced, the reason may be because vehicle was driven with a lack of fuel, improper fuel, fouled spark plug, etc.

DTC is set when misfiring cylinders is detected during any particular 200 or 1000 revolutions. Possible causes are

1. Open or short in engine wiring harness.
2. Defective connections at ECM or component.
3. Disconnected, restricted or damaged vacuum hose(s).
4. Ignition system malfunction.
5. Defective fuel injector(s).
6. Improper fuel pressure.
7. Defective Mass Airflow (MAF) meter.
8. Defective Engine Coolant Temperature (ECT) sensor.
9. Improper engine compression.
10. Improper valve clearance.
11. Improper valve timing.
12. Defective Positive Crankcase Ventilation (PCV) valve piping.
13. Defective ECM.

DTC is set when there is no knock sensor signal to ECM with engine speed is 2000 RPM or more. If DTC P0325 exists, ECM will operate in fail-safe mode which retards the ignition timing to a maximum setting. Possible causes are

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

DTC P0335 is set if no cranking signal is received by ECM from sensor or when no cranking signal is received by ECM at engine speed of 600 RPM or more. DTC P0339 is set if no NE signal is received by ECM from CKP sensor at 1000 RPM or more, NE signal is not detected for over 50 msec., or NE signal is not detected during cranking. Possible causes are

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

Possible causes are

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

DTCs P0351-P0354 are for ignitor on ignition coils No. 1-4 and are set when there is no IGF signal to ECM when engine is running. If DTCs P0351-P0354 exist, ECM will operate in fail-safe mode. Possible causes are

1. Ignition system malfunction.
2. IGF or IGT circuit from ignition coil to ECM is open or shorted.
3. Defective ignition coil or ignitor.
4. Defective ECM.

DTC is set when both oxygen sensors have same amplitude after vehicle is driven for 5 minutes at 20-50 MPH. Possible causes are

1. Exhaust system leak.
2. Heated oxygen sensor circuit is open or shorted.
3. Defective heated oxygen sensor.
4. Defective catalytic converter.

Confirmation Engine Racing Pattern

For confirmation engine racing pattern (Scheme 217)

Scheme 217

For DTC detection conditions and possible causes (Scheme 218)

Scheme 218

DTC is set if a leak is detected in EVAP system or vapor pressure sensor malfunctions. Possible causes are

1. Damaged, disconnected or restricted vacuum hose(s) or tubes.
2. Fuel tank cap is loose or improperly installed.
3. Defective fuel tank cap.
4. Damaged fuel tank.
5. Defective charcoal canister.
6. Vapor pressure sensor circuit is open or shorted.
7. Defective vapor pressure sensor.
8. Defective overfill check valve.
9. Defective ECM.

DTC is set if vapor pressure sensor malfunctions. Possible causes are

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

DTC is set if there is no VSS signal to ECM while vehicle is being driven and clutch or brake slips or when gear is broken (2 trip detection logic). Possible causes are

1. Defective vehicle speed sensor.
2. Vehicle speed sensor circuit is open or shorted.
3. Defective instrument cluster.
4. Defective ABS ECU.
5. Defective ECM.

DTC is set if stoplight switch does not turn off when vehicle is being driven for 0.5 seconds. Possible causes are

1. Stoplight switch signal circuit is shorted.
2. Defective stoplight switch.
3. Defective ECM.

DTC is set when idle speed continues to vary greatly from target speed. Possible causes are

1. Defective Positive Crankcase Ventilation (PCV) valve hose or connection.
2. IAC valve is stuck or remains closed.
3. IAC valve circuit is open or shorted.
4. A/C signal circuit is open or shorted.
5. Air induction system malfunction.
6. Defective ECM.

DTC will set when idle speed continues to vary greatly from target idle speed. Possible causes are

1. Air induction system.
2. Electric throttle control system.
3. PCV valve and/or hose.

If DTC P1600 exists, the ECM will not store any other DTCs. DTC is set when open in back-up power source is detected. Possible causes are

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

Possible Cause

If DTCs P0604, P0606, P0607 and/or P0657 exists, the ECM will not store any other DTCs. Cause is ECM.

DTC will set when at a vehicle speed of 12 MPH or more, an engine speed of 1000 RPM or more and STA signal ON, battery (+B) voltage is 10.5 volts or more. Possible causes are

1. Defective starter relay.
2. Open or short in STA signal circuit.
3. Defective ignition switch.
4. Defective ECM.

DTC P1126 is set when the magnetic clutch current is 1.4 amps or more or 0.4 amp or less for 0.8 second. Or, when magnetic clutch current is 1.0 amp or more or 0.8 amp or less for 1.5 seconds. Possible causes are

1. Open or short in magnetic clutch circuit.
2. Defective magnetic clutch.
3. Defective ECM.

DTC is set when ECM detects no communication from combination meter. Possible causes are

1. Defective ABS ECU.
2. Defective air bag sensor assembly.
3. Defective instrument cluster.
4. Defective A/C ECU.
5. Bus communications circuit is open or shorted.
6. Defective ECM.

DTC is set when no communication from transmission control Electronic Control Unit (ECU) is detected. Possible causes are

1. Defective transmission control ECU.
2. Bus communications circuit is open or shorted.
3. Defective ECM.

For DTC detection conditions and possible causes (Scheme 219)

Scheme 219

DTC is set when ECM detects a locked throttle control motor. Possible causes are

1. Defective throttle body assembly.
2. Defective throttle control motor.

DTC is set when ECM detects an open ETCS power source circuit. Possible causes are

1. ETCS power source circuit is open.
2. Defective ECM.

DTC is set when throttle opening angle varies greatly from target throttle opening angle. Possible causes are

1. Defective Throttle body.
2. Defective ECM.

DTC is set when ECM detects voltage is out of range on VPA circuit or VPA2 circuit. Possible cause is defective APP sensor.

DTC is set when, no communication from transmission control ECU continues. Possible causes are

1. Defective Transmission Control ECU.
2. Open or short in transmission control ECU circuit.
3. Defective ECM.