Engine Controls - Tests W/codes - 4-cyl Toyota 4Runner II

INTRODUCTION

If no faults were found while performing BASIC TESTING , proceed with self-diagnostics. If no fault codes or only pass codes are present after entering self-diagnostics, proceed to TESTS W/O CODES article in the ENGINE PERFORMANCE Section for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.).

HARD FAILURES

Hard failures cause malfunction light to illuminate and remain on until problem is repaired. If light comes on and remains on (light may flash) during vehicle operation, cause of malfunction must be determined using diagnostic (code) charts. If a sensor fails, control unit will use a substitute value in its calculations to continue engine operation. In this condition, commonly known as limp-in mode, the vehicle runs but driveability will not be optimum.

INTERMITTENT FAILURES

Intermittent failures may cause CHECK ENGINE light to flicker or illuminate and go out after the intermittent fault goes away. However, the corresponding trouble code will be retained in ECU memory. If related fault does not reoccur within a certain time frame, related trouble code will be erased from ECU memory. Intermittent failures may be caused by a sensor, connector or wiring related problems. See INTERMITTENTS in TESTS W/O CODES article in the ENGINE PERFORMANCE Section.

Scheme 39

Scheme 40

1. Before retrieving codes, verify CHECK ENGINE light comes on with ignition on and engine off. The CHECK ENGINE light should go off when engine is started. If CHECK ENGINE light does not come on, see appropriate DIAGNOSTIC CIRCUIT CHECK under CODE CHARTS. If light remains on, system has detected a malfunction or abnormality.
2. Ensure battery voltage is greater than 11 volts and charging system is okay. Engine should be at normal operating temperature.
3. Apply parking brake. Shift transaxle to Neutral (M/T) or Park (A/T). Turn A/C and all accessories off. Close throttle valve.
4. Turn ignition on with engine off. Install jumper wire between terminals TE1 (or T) and E1 in engine check connector. (Scheme 39)
5. Count number of flashes from CHECK ENGINE light. If system is operating properly (with no codes), CHECK ENGINE light will flash continuously and evenly. (Scheme 40) NOTE: If CHECK ENGINE light will not flash diagnostic codes, see appropriate DIAGNOSTIC CIRCUIT CHECK under CODE CHARTS.
6. If code exists, digits of each code will flash at 1/2-second intervals, with a 1 1/2-second pause between first and second digits. (Scheme 40)
7. If more than one code is stored, a 2 1/2-second pause will occur before next code is flashed. Once all codes are displayed, a 4 1/2-second pause will occur then code(s) will be repeated.
8. Codes are displayed from the smallest to largest code. After codes are retrieved, remove jumper wire to exit diagnostic mode.

NOTES ON CODES

1. No other code will appear with Code 11.
2. When Codes 25, 26, 27 and 71 initially happen, they will be temporarily stored in ECU memory, but CHECK ENGINE light will not come on. The second time code is detected, CHECK ENGINE light will then come on. This is referred to as the 2 trip detection logic.
3. After malfunction is repaired, CHECK ENGINE light will go off, but codes (except 51 and 53) will remain in ECU memory until code is cleared.

CLEARING CODES

1. After repairs are performed, clear ECU memory of all stored codes. To clear memory, turn ignition off. Remove EFI (15 amp) fuse from main fuse block in engine compartment fuse/relay box for approximately 30 seconds or more.
2. Depending on ambient temperature, fuse may need to be removed for more than 30 seconds. Replace fuse and exit diagnostic mode. Codes can also be cleared by disconnecting vehicle battery. However, other memory functions (clock, radio, etc.) will need to be reset.

ECU LOCATION

ECU is located behind right kick panel.

SUMMARY

If no hard fault codes (or only pass codes) are present, driveability symptoms exist or intermittent codes exist, proceed to TESTS W/O CODES article in the ENGINE PERFORMANCE Section for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.

SELF-DIAGNOSTICS

Note. Code diagnostic hints table may be used to determine a common cause for a code to be set.

CODE DIAGNOSTIC HINTS

CODE IDENTIFICATION

CODE IDENTIFICATION

CODE CHARTS

Note. All schematics and diagnostic flow charts are courtesy of Toyota Motor Sales, U.S.A., Inc.

ECU TERMINAL IDENTIFICATION

ECU Terminal Identification (Pickup 2WD). Scheme 41

ECU Terminal Identification (Pickup 4WD A/T). Scheme 42

ECU Terminal Identification (Pickup 4WD M/T). Scheme 43

ECU Terminal Identification (4Runner 4WD M/T & 2WD). Scheme 44

ECU Terminal Identification (4Runner 4WD A/T). Scheme 45

Diagnostic Circuit Check Schematic. Scheme 46

Diagnostic Circuit Check Flow Chart. Scheme 47

TEST NO. 1 - ECU (+B) CIRCUIT

TEST NO. 1-ECU (+B) CIRCUIT TROUBLE

Test No. 1 Schematic ECU (+B) Circuit. Scheme 48

Test No. 1 Flow Chart, Terminals BATT - E1 ECU (+B) Circuit. Scheme 49

Test No. 1 Flow Chart, Terminals +B(+B1) - E1 ECU (+B) Circuit. Scheme 50

CODE 12, 13 - RPM SIGNAL

Code 12 is caused by loss of "NE" signal from distributor to ECU for at least 2 seconds after starter signal is received at ECU. Ensure starter signal exists at ECU. See TEST NO. 7 OR CODE 43. Code 13 is caused by loss of "NE" signal from distributor to ECU when engine RPM exceeds 1500 RPM.

Note. Diagnostic chart not available from manufacturer.

CODE 14/TEST NO. 2 - IGNITION SIGNAL

Note. To check ignition system components, see I - SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.

CODE 14/TEST NO. 2-IGNITION SIGNAL TROUBLE

Code 14/Test No. 2 Schematic Ignition Signal. Scheme 51

Code 14/Test No. 2 Flow Chart Ignition Signal. Scheme 52

CODE 21, 27/TEST NO. 3 - OXYGEN SENSOR SIGNAL

Note. Code 27 applies to Pickup only.

Code 21, 27/Test No. 3 Schematic (Pickup) Oxygen Sensor Signal. Scheme 53

Code 21/Test No. 3 Schematic (4Runner) Oxygen Sensor Signal. Scheme 54

Code 21, 27/Test No. 3 Flow Chart Oxygen Sensor Signal. Scheme 55

CODE 22/TEST NO. 4 - COOLANT TEMPERATURE SENSOR SIGNAL

Note. Water temperature sensor is also referred to as coolant temperature sensor.

CODE 22/TEST NO. 4-CTS SENSOR SIGNAL TROUBLE

Code 22/Test No. 4 Schematic Coolant Temperature Sensor Signal. Scheme 56

Code 22/Test No. 4 Flow Chart Coolant Temperature Sensor Signal. Scheme 57

CODE 24, 31/TEST NO. 5 - IAT SENSOR & AIRFLOW METER SIGNAL

CODE 24/TEST NO. 5-IAT SENSOR SIGNAL TROUBLE

Code 24, 31/Test No. 5 Schematic Intake Air Temp. Sensor & Airflow Meter Signal. Scheme 58

Code 24, 31/Test No. 5 Flow Chart, Terminals Vc - E2 (E21) Intake Air Temp. Sensor & Airflow Meter Signal. Scheme 59

Code 24, 31/Test No. 5 Flow Chart, Terminals Vs - E2 (E21) Intake Air Temp. Sensor & Airflow Meter Signal. Scheme 60

Code 24, 31/Test No. 5 Flow Chart, Terminals THA - E2 (E21) Intake Air Temp. Sensor & Airflow Meter Signal. Scheme 61

Probable Causes

1. Airflow Meter
2. Air Intake System
3. Coolant Temperature Sensor
4. Fuel Pressure
5. Ignition System
6. Injector Circuit or Injector
7. Oxygen Sensor or Sensor Circuit
8. ECU

Note. Diagnostic chart not available from manufacturer.

1. Airflow Meter
2. Cold Start Injector
3. Coolant Temperature Sensor
4. ECU
5. Fuel Pressure
6. Injector Circuit or Injector
7. Oxygen Sensor or Sensor Circuit

Note. Diagnostic chart not available from manufacturer.

CODE 41/TEST NO. 6 - THROTTLE POSITION SENSOR SIGNAL

CODE 41/TEST NO. 6-TPS SENSOR SIGNAL TROUBLE

Code 41/Test No. 6 Schematic Throttle Position Sensor Signal. Scheme 62

Code 41/Test No. 6 Flow Chart, Terminals IDL - E2 (E21) Throttle Position Sensor Signal. Scheme 63

Code 41/Test No. 6 Flow Chart, Terminals Vcc - E2 (E21) Throttle Position Sensor Signal. Scheme 64

Code 41/Test No. 6 Flow Chart, Terminals VTA - E2 (E21) Throttle Position Sensor Signal. Scheme 65

1. Vehicle Speed Sensor or Sensor Circuit
2. ECU

Note. Diagnostic chart not available from manufacturer.

CODE 43/TEST NO. 7 - STARTER SIGNAL

CODE 43/TEST NO. 7-STARTER SIGNAL TROUBLE

Code 43/Test No. 7 Schematic Starter Signal. Scheme 66

Code 43/Test No. 7 Component Diagram Starter Signal. Scheme 67

Code 43/Test No. 7 Flow Chart Starter Signal. Scheme 68

1. Accelerator Pedal or Cable
2. ECU
3. Neutral/Start Switch or Switch Circuit
4. Throttle Position Sensor or Sensor Circuit

Note. Diagnostic chart not available from manufacturer.

1. Knock Sensor or Sensor Circuit
2. ECU

Note. Diagnostic chart not available from manufacturer.

1. ECU

Note. Diagnostic chart not available from manufacturer.

Code 71/Test No. 8 Schematic EGR System Malfunction. Scheme 69

Code 71/Test No. 8 Flow Chart EGR System Malfunction. Scheme 70

TEST NO. 9 - INJECTOR CIRCUIT

TEST NO. 9-INJECTOR CIRCUIT TROUBLE

Test No. 9 Schematic Injector Circuit. Scheme 71

Test No. 9 Flow Chart Injector Circuit. Scheme 72

TEST NO. 10 - COLD START INJECTOR CIRCUIT

TEST NO. 10-COLD START INJECTOR CIRCUIT TROUBLE

Test No. 10 Schematic Cold Start Injector Circuit. Scheme 73

Test No. 10 Flow Chart Cold Start Injector Circuit. Scheme 74

TEST NO. 11 - CHECK ENGINE LIGHT CIRCUIT

TEST NO. 11-CHECK ENGINE LIGHT CIRCUIT TROUBLE

Test No. 11 Schematic Check Engine Light Circuit. Scheme 75

Test No. 11 Flow Chart Check Engine Light Circuit. Scheme 76

TEST NO. 12 - STOPLIGHT SWITCH CIRCUIT

TEST NO. 12 - STOPLIGHT SWITCH CIRCUIT TROUBLE

Test No. 12 Schematic Stoplight Switch Circuit. Scheme 77

Test No. 12 Flow Chart Stoplight Switch Circuit. Scheme 78

See also:
• 12 & 13
• 14
• 21
• 22
• 24
• 25
• 41
• 43