Inspection Procedure

HINT:

Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.

Check spark plug and spark of misfiring cylinder (see ON-VEHICLE INSPECTION in IGNITION article).
1. NG : Go to step 4 .
2. OK : Go to next step.
Check for open and short in wire harness in IGF and IGT signal circuit between ECM and ignition coil with igniter (see HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE in INTRODUCTION article).
1. NG : Replace harness and connector.
2. OK : Go to next step.
Disconnect ignition coil with igniter connector and check voltage between terminal IGF1 of ECM connector and body ground.
PREPARATION:
1. Remove the glove compartment (see COMPONENTS ).
2. Disconnect the ignition coil with igniter connector.
3. Turn the ignition switch ON.
CHECK:

Measure the voltage between terminal IGF1 of the ECM connector and body ground.

OK:

Voltage: 4.5 to 5.5 V

Fig 1: Locating IGF1 (+) Connector Terminal Of ECM
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG : Replace ECM (see COMPONENTS ).
2. OK : Replace ignition coil with igniter.
Check for open and short in wire harness in IGT signal circuit between ECM and ignition coil with igniter (see HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE in INTRODUCTION article).
1. NG : Repair or replace harness and connector.
2. OK : Go to next step.
Check voltage between terminals IGT1 to IGT4 of ECM connector and body ground.
PREPARATION:

Remove the glove compartment (see COMPONENTS ).

CHECK:

Measure the voltage between terminals IGT1 to IGT4 of the ECM connector and the body ground when the engine is cranked.

OK:

Voltage: More than 0.1 V and less than 4.5 V

Fig 2: Locating IGT1, IGT2, IGT3, IGT4 Connector Terminals Of ECM And Body Ground
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Reference: INSPECTION USING OSCILLOSCOPE

During cranking or idling, check the waveform between terminals IGT1 to IGT4 and E1, and IGF1 and E1 of the ECM connector.

HINT:

The correct waveforms are as shown in the illustration.

Fig 3: Inspecting Signal Waveform
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG : Replace ECM (see COMPONENTS ).
2. OK : Go to next step.
Disconnect ignition coil with igniter connector and check voltage between terminals IGT1 to IGT4 of ECM connector and body ground.
PREPARATION:
1. Remove the glove compartment (see COMPONENTS ).
2. Disconnect the ignition coil with igniter connector.
CHECK:

Measure the voltage between terminals IGT1 to IGT4 of the ECM connector and the body ground when the engine is cranked.

OK:

Voltage: More than 0.1 V and less than 4.5 V

Fig 4: Locating IGT1, IGT2, IGT3, IGT4 Connector Terminals Of ECM And Body Ground
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG : Replace ECM (see COMPONENTS ).
2. OK : Go to next step.
Check ignition coil with igniter power source circuit.
PREPARATION:

Disconnect the ignition coil with igniter connector.

CHECK:

Measure the voltage between terminal 1 of the ignition coil with igniter connector and the body ground when the ignition switch is turned the to ON or START position.

OK:

Voltage: 9 to 14 V

Fig 5: Identifying Ignition Coil Igniter Power Source Circuit Connector Terminal 1 (+)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG : Repair ignition coil with igniter power source circuit.
2. OK : Go to next step.
Check for open and short in are wire harness between ignition switch and ignition coil with igniter (see HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE in INTRODUCTION article).
1. NG : Repair or replace harness and connector.
2. OK : Replace ignition coil with igniter.