Inspection Procedure

WARNING: This page is about a different variant/trim than selected.

HINT: Read freeze frame data using a hand-held tester or OBD II scan tool. Freeze frame data record the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, 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.

INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)

Disconnect the H5 or H8 Heated Oxygen (HO2) sensor connector.

Measure the resistance between the terminals of the HO2 sensor connector.

Standard:

HEATED OXYGEN SENSOR (HEATER RESISTANCE)

Tester Connections	Specified Conditions
HT (H5-2) - +B (H5-1)	Between 5 Ω and 10 Ω at 20 °C (68 °F)
HT (H5-2) - E (H5-3)	10 kΩ or higher
HT (H8-2) - +B (H8-1)	Between 11 Ω and 16 Ω at 20 °C (68 °F)
HT (H8-2) - E (H8-3)	10 kΩ or higher

Reconnect the HO2 sensor connector.

Fig 1: Inspecting Heated Oxygen Sensor (Heater Resistance)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: REPLACE HEATED OXYGEN SENSOR
OK: GO TO NEXT STEP

INSPECT EFI RELAY

Remove the EFI relay from the engine room R/B.

Check the EFI relay resistance.

Standard:

EFI RELAY RESISTANCE

Tester Connections	Specified Conditions
3 - 5	10 kΩ or higher
3 - 5	Below 1 Ω (When battery voltage applied to terminals 1 and 2)

Reinstall the EFI relay.

Fig 2: Inspecting EFI Relay
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: REPLACE EFI RELAY
OK: GO TO NEXT STEP

INSPECT ECM (HT1A OR HT1B VOLTAGE)

Turn the ignition switch to ON.

Measure the voltage between the terminals of the E4 and E6 ECM connectors.

Standard:

ECM (HT1A OR HT1B VOLTAGE) VOLTAGE

Tester Connections	Specified Conditions
HT1A (E4-6) - E03 (E4-7)	Between 9 V and 14 V
HT1B (E6-7) - E03 (E4-7)	Between 9 V and 14 V

Fig 3: Inspecting ECM (HT1A Or HT1B Voltage)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: REPLACE ECM (See ECM (1ZZ-FE/2ZZ-GE) REPLACEMENT )
NG: GO TO NEXT STEP

CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - ECM, HEATED OXYGEN SENSOR - EFI RELAY)

Check the harness and connectors between the ECM and HO2 sensor.

Disconnect the H5 or H8 HO2 sensor connector.
Disconnect the E4 or E6 ECM connector.

Check the resistance.

Standard (Check for open):

HEATED OXYGEN SENSOR - ECM, HEATED OXYGEN SENSOR - EFI RELAY RESISTANCE (CHECK FOR OPEN)

Tester Connections	Specified Conditions
HT (H5-2) - HT1A (E4-6)	Below 1 Ω
HT (H8-2) - HT1B (E6-7)	Below 1 Ω

Fig 4: Identifying Terminals Of Heated Oxygen Sensor Connector

Standard (Check for short):

HEATED OXYGEN SENSOR - ECM, HEATED OXYGEN SENSOR - EFI RELAY RESISTANCE (CHECK FOR SHORT)

Tester Connections	Specified Conditions
HT (H5-2) or HT1A (E4-6) - Body ground	10 kΩ or higher
HT (H8-2) or HT1B (E6-7) - Body ground	10 kΩ or higher

Reconnect the HO2 sensor connector.
Reconnect the ECM connector.

Check the harness and connectors between the HO2 sensor and EFI relay.

Disconnect the H5 or H8 HO2 sensor connector.
Remove the EFI relay from the engine room R/B.

Fig 5: Disconnecting E4 And E6 ECM Connector
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Check the resistance.

Standard (Check for open):

HO2 SENSOR AND EFI RELAY RESISTANCE (CHECK FOR OPEN)

Tester Connections	Specified Conditions
+B (H5-2) - EFI relay (3)	Below 1 Ω
+B (H8-1) - EFI relay (3)	Below 1 Ω

Standard (Check for short):

HO2 SENSOR AND EFI RELAY RESISTANCE (CHECK FOR SHORT)

Tester Connections	Specified Conditions
+B (H5-2) or EFI relay (3) - Body ground	10 kΩ or higher
+B (H8-1) or EFI relay (3) - Body ground	10 kΩ or higher

Reconnect the HO2 sensor connector.

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: GO TO NEXT STEP
REPLACE ECM (See ECM (1ZZ-FE/2ZZ-GE) REPLACEMENT )