Engine Control System Self Diagnostics - 1GR-FE: Other Toyota 4Runner IV

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 (DLC3). DLC3 is located at driver's side of instrument panel. (Scheme 825)

Scheme 825

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 be used to read freeze frame data.

EVAP Monitor & Drive Cycle Pattern

For EVAP monitor and drive cycle pattern (Scheme 826)and (Scheme 827).

Scheme 826

Scheme 827

Heated Oxygen Sensor Monitor & Drive Cycle Pattern

For heated oxygen sensor monitor and drive cycle pattern (Scheme 828)

Scheme 828

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 829)

Scheme 829

Catalyst Monitor & Drive Cycle Pattern

For catalyst monitor and drive cycle pattern (Scheme 830)

Scheme 830

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 article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.

Scheme 831

1. If Toyota hand-held tester or scan tool displays UNABLE TO CONNECT TO VEHICLE when hand-held tester or scan tool is connected to Data Link Connector No. 3 (DLC3), try hand-held tester or scan tool on another vehicle. If hand-held tester or scan tool operates on another vehicle, go to next step. If hand-held tester or scan tool does not operate on another vehicle, problem is probably with hand-held tester or scan tool.
2. Check voltage and resistance between ground and specified terminal on DLC3. See «DATA LINK CONNECTOR VOLTAGE & RESISTANCE SPECIFICATIONS»(ref-157557-S28678319462003081500000). (Scheme 831) If voltage or resistance are not within specification, check wiring circuit. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. For full wiring diagram of DLC3, it may be necessary to see appropriate DATA LINK CONNECTORS article in WIRING DIAGRAMS. DATA LINK CONNECTOR VOLTAGE & RESISTANCE SPECIFICATIONS Terminal No. (Circuit) Specification 4 (Chassis Ground) 1 Ohm Or Less 5 (Signal Ground) 1 Ohm Or Less 7 (BUS Communication) (1) 16 (Battery Voltage) 9-14 Volts (1) Pulse generation should exist during information transmission from Engine Control Module (ECM).

SUMMARY

If no Diagnostic Trouble Codes (DTC) are present and a no start condition exists, proceed to BASIC DIAGNOSTIC PROCEDURES - V6 & V8 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

Possible causes are

1. Open or short in OCV circuit.
2. Defective OCV.
3. Defective ECM.

DTCs P0011 and P0021 will set when valve timing does not change from current valve timing or current valve timing is fixed and continues after engine is warmed up at an engine speed of 400-4000 RPM (a problem of the advanced OCV). DTCs P0012 & P0022 will set when valve timing does not change from current valve timing or current valve timing is fixed and continues after engine is warmed up and engine speed at 400-4000 RPM (a problem of the retarded OCV). Possible causes are

1. Defective OCV.
2. Defective camshaft gear assembly.
3. Incorrect valve timing.
4. Defective ECM.

DTC P0016 is set when there is a deviation between crankshaft position sensor signal and VVT sensor 1 signal (2 trip detection logic). DTC P0018 is set when there is a deviation between crankshaft position sensor signal and VVT sensor 2 signal (2 trip detection logic). Possible causes are

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

DTCs P0031 and P0051 will set when heater current is 0.8 amp or less during heater operation (one trip detection logic).

DTCs P0032 and P0052 will set when heater current exceeds 19.7 amps when heater operates (one trip logic detection).

Possible causes are

1. Open or short in heater circuit of A/F sensor.
2. Defective A/F sensor heater.
3. Defective A/F sensor heater relay.
4. Defective ECM.

DTCs P0037 and P0057 will set when heater current is 0.25 amp or less when heater operates with +B voltage of 11.5 volts or more (one trip detection logic).

DTCs P0038 and P0058 will set when heater current exceeds 2 amps when heater operates (one trip logic detection).

Possible causes are

1. Open or short in heater circuit of heated oxygen sensor.
2. Defective heated oxygen sensor heater.
3. Defective EFI relay.
4. Defective ECM.

DTC is set when

1. For DTC P0100, an open or short in mass air flow meter circuit for more than 3 seconds at an engine speed 4,000 RPM or less.
2. For DTC P0102, an open in mass air flow meter circuit for more than 3 seconds at an engine speed 4,000 RPM or less.
3. For DTC P0103, a short in mass air flow meter circuit (+B circuit) for more than 3 seconds at an engine speed 4,000 RPM or less.

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 .63 volt or more with engine speed of 1500 RPM or more. Possible cause is defective MAF meter.

DTC will set when

1. For DTC P0110, there is an open or short in intake air temperature sensor circuit for 0.5 second.
2. For DTC P0112, there is a short in intake air temperature sensor circuit for 0.5 second.
3. For DTC P0113, there is an open in intake air temperature sensor circuit for 0.5 second.

Possible causes are

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

DTC is set when

1. For DTC P0115, there is an open or short in engine coolant temperature sensor circuit for 0.5 second.
2. For DTC P0117, there is a short in engine coolant temperature sensor circuit for 0.5 second.
3. For DTC P0118, there is an open in engine coolant temperature sensor circuit for 0.5 second.

Possible causes are

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

Possible causes are

1. Defective ECT sensor.
2. Defective cooling system thermostat.

DTC(s) will set when

1. For DTC P0120, detection conditions for DTCs P0122 and P0123 are not satisfied, but VTA1 is 0.2 volt or less, or VTA1 4.8 volts or more. Trouble areas would be: defective throttle position sensor (built in throttle body) or defective ECM.
2. For DTC P0122, VTA1 is 0.2 volt or less. Trouble areas would be: defective throttle position sensor (built in throttle body), short in VTA1 circuit, open in VC circuit or defective ECM.
3. For DTC P0123, VTA1 is 4.8 volts or more. Trouble areas would be: defective throttle position sensor (built in throttle body), open in VTA1 circuit, open in E2 circuit, VC and VTA1 circuit are short-circuited or defective ECM.
4. For DTC P0220, detection conditions for DTCs P0222 and P0223 are not satisfied but VTA2 is 0.5 volt or less, or 4.8 volts or more and VTA1 is 0.2 volt less, or 1.8 volts or more. Trouble areas would be: defective throttle position sensor (built in throttle body) or defective ECM.
5. For DTC P0222, VTA2 is 0.5 volt or less. Trouble areas would be: defective throttle position sensor (built in throttle body), short in VTA2 circuit, open in VC circuit or defective ECM.
6. For DTC P0223, VTA2 is 4.8 volts or more and VTA1 is 0.2 volt or less, or 1.8 volts or more. Trouble areas would be: defective throttle position sensor (built in throttle body), open in VTA2 circuit, open in E2 circuit, VC and VTA2 circuit are short-circuited or defective ECM.
7. For DTC P2135, VTA1 and VTA2 are 0.02 volt and continues for 0.5 second or more, or VTA1 is 0.2 volt or less and VTA2 is 0.5 volt or less and continues for 0.4 second or more. Trouble areas would be: VTA1 and VTA2 circuit are short-circuited, defective throttle position sensor (built in throttle body) or defective ECM.

Possible Cause

This DTC uses two-trip detection logic. DTC is set when improper input signals from TP sensor are received at ECM. If DTC P0121 exists, ECM will turn off the power to throttle control motor and throttle valve is closed by the return spring. When this occurs, throttle valve is controlled by throttle cable connected to accelerator pedal. Possible cause is defective TP sensor.

DTC is set when ECM detects engine coolant temperature is less than 167°F (75°C) when engine should be at normal operating temperature. Possible causes are

1. Defective cooling system thermostat.
2. Defective Engine coolant temperature sensor.
3. Defective ECM.

This DTC uses two-trip detection logic. DTC is set when heated oxygen sensor output voltage remains at 0.40 volt or more, or 0.50 volt or less when vehicle is driven at 31 MPH with engine at normal operating temperature. Possible causes are

1. Heated oxygen sensor circuit is open or shorted (B1 & 2, S2).
2. Defective heated oxygen sensor (B1 & 2, S2).
3. Defective heated oxygen sensor heater (B1 & 2, S2).
4. Defective EFI relay.

Note. When DTCs P0171 or P0174 is recorded, the actual air-fuel ratio is on the LEAN side. A low heated oxygen sensor (S 1) voltage of 0.4 volt or less could be caused by a lean air fuel mixture. Check for conditions that would cause the engine to run lean.

DTCs P0171 and P0174 is set when air-fuel ratio feedback is stable after warming up engine, fuel trim is considerably in error on LEAN side (2 trip detection logic). Possible causes are

1. Air induction system malfunction.
2. Fuel injector restricted.
3. Defective Mass Airflow (MAF) meter.
4. Defective Engine Coolant Temperature (ECT) sensor.
5. Improper fuel pressure.
6. Exhaust system leak.
7. Air/Fuel (A/F) sensor circuit is open or shorted.
8. Defective A/F sensor.
9. Defective A/F sensor heater.
10. Defective A/F sensor heater relay.
11. Defective Positive Crankcase Ventilation (PCV) valve hose or connection.
12. Vehicle ran out of fuel.

Note. When DTCs P0172 or P0175 is recorded, the actual air-fuel ratio is on the RICH side. A high heated oxygen sensor (S 1) voltage of 0.55 volt or more could be caused by a rich air fuel mixture. Check for conditions that would cause the engine to run rich.

DTCs P0172 and P0175 is set when air-fuel ratio feedback is stable after warming up engine, fuel trim is considerably in error on RICH side (2 trip detection logic). Possible causes are

1. Fuel injector restricted or leaking.
2. Defective Mass Airflow (MAF) meter.
3. Defective Engine Coolant Temperature (ECT) sensor.
4. Ignition system malfunction.
5. Improper fuel pressure.
6. Exhaust system leak.
7. Air/Fuel (A/F) sensor circuit is open or shorted.
8. Defective A/F sensor.
9. Defective A/F sensor heater.
10. Defective A/F sensor heater relay.
11. Defective Positive Crankcase Ventilation (PCV) valve hose or connection.
12. Defective ECM.
13. Vehicle ran out of fuel.

Note. If the total of the short-term fuel trim value and long-term fuel trim value is within plus or minus 35 percent at 167°F (75°C), the system is functioning normally.

DTC will set when an open or short circuit in fuel pump relay has been detected. Possible causes are

1. Open or short in fuel pump relay circuit.
2. Defective fuel pump relay.
3. ECM.

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 hose or connection.
13. Defective ECM.

DTC is set when

1. For DTC P0325, output voltage of the knock sensor 1 decreases beyond a threshold. (Threshold varies according to engine speed). Possible causes are: knock sensor 1 (defective or loose), or defective ECM.
2. For DTC P0327, output voltage from knock sensor 1 is 0.5 volt or less. Possible causes are: defective knock sensor 1, short in knock sensor 1 circuit or defective ECM.
3. For DTC P0328, output voltage from knock sensor 1 is 4.5 volts or more. Possible causes are: defective knock sensor 1, open in knock sensor 1 circuit, or defective ECM.
4. For DTC P0330, output voltage of the knock sensor 2 decreases beyond a threshold. (Threshold varies according to engine speed). Possible causes are: knock sensor 2 (defective or loose), or defective ECM.
5. For DTC P0332, output voltage from knock sensor 2 is 0.5 volt or less. Possible causes are: defective knock sensor 2, short in knock sensor 2 circuit or defective ECM.
6. For DTC P0333, output voltage from knock sensor 2 is 4.5 volts or more. Possible causes are: defective knock sensor 2, open in knock sensor 1 circuit, or defective ECM.

DTC P0335 is set when ECM does not receive input signal from crankshaft position sensor with engine cranking or with engine speed 600 RPM or more (2 trip detection logic). DTC P0339 is set when no crankshaft position sensor (NE) signal is input for 0.05 second or more with engine speed of 1000 RPM or more, STA signal is OFF and 3 seconds or more has lapsed after STA signal is switched from ON to OFF. Possible causes are

1. Crankshaft position sensor circuit is open or shorted.
2. Defective crankshaft position sensor.
3. Defective signal plate on crankshaft sprocket.
4. Defective ECM.

DTC is set when

1. For DTCs P0340 & P0345, no VVT sensor signal to ECM during cranking (2 trip detection logic) or no VVT sensor signal to ECM with engine speed 600 RPM or more (1 trip detection logic).
2. For DTCs P0341 & P0346, while crankshaft rotates twice, VVT sensor signal is input to ECM 12 times or more (1 trip detection logic).

Possible causes are

1. Open or short in VVT sensor circuit.
2. Defective VVT sensor.
3. Defective camshaft timing pulley.
4. Jumping teeth of timing chain.
5. Defective ECM.

DTCs P0351-P0356 are for ignitor on ignition coils No. 1-6 and are set when there is no IGF signal to ECM when engine is running. If DTCs P0351-P0356 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.

This DTC uses two-trip detection logic. DTC is set when A/F sensor and heated oxygen sensor have nearly the same waveform pattern after engine and catalytic converter are at normal operating temperature and vehicle is driven. Possible causes are

1. Exhaust system leak.
2. Defective A/F sensor (B1 & 2, S1).
3. Defective heated oxygen sensor (B1 & 2, S2).
4. Defective three way catalytic converter.

Confirmation Engine Racing Pattern

Use this pattern procedure to monitor oxygen sensor (B1 & 2, S2) waveform to determine sensor switching frequency, which is a useful tool in determining catalyst condition (deterioration). see scheme 82

1. Connect hand-held tester to Data Link Connector No. 3 (DLC3) at driver's side of instrument panel. (Scheme 825) Turn ignition on and then turn hand-held tester on.
2. Start engine and warm it up with all the accessories switched OFF until the water temperature is stable.
3. Race the engine at 2500-3000 RPM for about 3 minutes.
4. When racing the engine at 3000 RPM for 2 seconds and 2000 RPM for 2 seconds, alternately check the waveform of the oxygen sensor (B1 & 2, S2). see scheme 82

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 inlet pipe or 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 on fuel tank.
9. Defective ECM.

EVAP Leak Check

1. Connect hand-held tester to Data Link Connector No. 3 (DLC3) at driver's side of instrument panel. (Scheme 825) Turn ignition on and then turn hand-held tester on.
2. Select ENHANCED OBD II/SYSTEM CHECK/EVAP SYS CHECK (or EVAP LEAK TEST) mode on the hand-held tester.
3. If any changes do not occur within 1 minute after pressing EVAP LEAK TEST, remove the fuel tank cap, then install the fuel tank cap again. Perform EVAP SYS CHECK (or EVAP LEAK TEST). The display on the hand held tester will indicate either, Scan tool detects a leak on the EVAP system, or Scan tool does not detect a leak on the EVAP system NOTE: If a leak is detected during this leak test, or if DTCs P0441, P0442 and P0446 were output simultaneously, conduct a leak test again after repair. Go to «DIAGNOSIS & REPAIR»(ref-157557-S34940349702003081500000). If no leak is found at this time, the EVAP system is recovered to normal. Check for intermittent condition.

DTCs P0451, P0452 or P0453 is set by the ECM when the VPS malfunctions. Possible causes are

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

DTC will set when ECM detects no SP1 (speed sensor) signal while ECM detects SP2 (No. 2 speed sensor) signal and vehicle speed is 6 MPH or more for 4 seconds, Park/Neutral position switch is OFF (except P and N position) and transfer case in any position except N position (4WD) (2 trip detection logic). Possible causes are

1. Vehicle speed circuit is open or shorted between combination meter (instrument cluster) and ECM.
2. Defective combination meter (instrument cluster).
3. Defective speed sensor.
4. Defective ECM.
5. Defective skid control ECU.

For DTC detection conditions and possible causes (Scheme 832)

Scheme 832

DTC is set when idle speed continues to vary greatly from target speed (2 trip detection logic). Possible causes are

1. Defective Positive Crankcase Ventilation (PCV) valve hose or connection.
2. Defective ETCS.
3. Air induction system malfunction.

Possible causes are open in back-up power source circuit or a defective ECM.

DTC will set when all conditions are satisfied, (vehicle speed of 6 MPH or more, engine speed of 1000 RPM or more and STA signal ON), battery voltage is 10.5 volts or more for 20 seconds. Possible causes are

1. Short in Park/Neutral position switch circuit.
2. Defective Park/Neutral position switch.
3. Cranking holding function circuit.
4. Defective ECM.

DTC P2102 will set when throttle control motor output duty is 80 percent or more and throttle control motor current is less than 0.5 amp for 2 seconds.

Possible causes are

1. Open in throttle control motor circuit.
2. Defective throttle control motor.
3. Defective ECM.

DTC P2103 will set when throttle control motor current is 10 amps or more. Or, when throttle control motor current is 7 amps or more for 0.6 second.

Possible causes are

1. Short in throttle control motor circuit.
2. Defective throttle control motor.
3. Defective ECM.

1. DTC P2111 will set when throttle motor is stuck open during control by the ECM.
2. DTC P2112 will set when throttle motor is stuck closed during control by the ECM.

Possible causes are

1. Short or open in throttle control motor circuit.
2. Throttle control motor is defective.
3. Throttle body is defective.
4. Throttle valve is defective.

DTC is set if battery voltage does not exist on +BM circuit at ECM for ETCS. If DTC P2118 exists, ECM will turn off the power to throttle control motor and throttle valve is closed by the return spring. The throttle valve is locked at a certain opening angle. Also, the whole electronically controlled throttle operation is cancelled until the system returns to normal and the ignition switch is turned OFF. 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. If DTC P2119 exists, ECM shuts down the power for the throttle motor, and the throttle valve is fully closed by the return spring. And the throttle valve is locked at a certain opening angle. Also, the whole electronically controlled throttle operation is cancelled until the system returns to normal and the ignition switch is turned OFF. Possible causes are

1. Defective ETCS.
2. Defective ECM.

For DTC detection conditions and possible causes (Scheme 833)

Scheme 833

DTC is set when ECM determines voltage is out of range on VPA1 or VPA2 circuits between accelerator pedal position sensor and ECM. ECM determines the current opening angle of the accelerator pedal from these inputs and controls the throttle motor based on these signals. Possible causes are

1. Accelerator pedal position sensor circuit is open or shorted.
2. Defective accelerator pedal position sensor.
3. Defective ECM.

DTC is set when A/F sensor output voltage does not change after engine is started with engine at normal operating temperature. This DTC uses two-trip detection logic. Possible causes are

1. A/F sensor (B1 & 2, S1) circuit is open or shorted.
2. Defective A/F sensor (B1 & 2, S1).
3. Defective A/F sensor heater (B1 & 2, S1).
4. Defective A/F sensor heater relay and/or circuit.
5. Air induction system malfunction.
6. Improper fuel pressure.
7. Defective fuel injector.
8. Vehicle has run out of fuel.
9. Defective ECM.

DTC will set when AF+ voltage remains 4.5 volts or more for 5 seconds or more, or when AF+ voltage remains 0.5 volt or less for 5 seconds or more. Also, when AF+ minus AF- is 0.1 volt or less for 5 seconds or more, or when AF+ minus AF- is 0.8 volt or more for 5 seconds or more. Possible causes are

1. Open or short in A/F sensor circuit.
2. Defective A/F sensor.
3. A/F sensor heater and relay circuit.
4. Defective A/F sensor heater relay.
5. Defective ECM.

DTC is set when response of A/F sensor becomes deteriorated when vehicle is being driven at 38 MPH or more with engine at normal operating temperature and engine speed of 1400 RPM or more. Possible causes are

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