Inspection Procedure

HINT:

Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air/fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
When DTC P0038 is detected, proceed to step 4 if the heater resistance is in normal range.

INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)

Disconnect the H13 heated oxygen sensor connector.

Measure the resistance between the terminals of the heated oxygen sensor connector.

Standard resistance (Bank 1 sensor 2):

TESTER CONNECTION SPECIFIED CONDITION

Tester Connection	Specified Condition
H13-1 (HT) - H13-2 (+B)	11 to 16 Ω at 20°C (68°F)
H13-1 (HT) - H13-4 (E)	10 kΩ or higher

Reconnect the heated oxygen sensor connector.

NG: REPLACE HEATED OXYGEN SENSOR

Fig 1: Identifying Heated Oxygen Sensor Connectors

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Go to next step

INSPECT INTEGRATION RELAY (EFI M RELAY)

Remove the integration relay from the engine room relay block.

Inspect the EFI M relay.

Standard resistance

TESTER CONNECTION SPECIFIED CONDITION

Tester Connection	Specified Condition
3K-1 - 3I-8	10 kΩ or higher
3K-1 - 3I-8	Below 1 Ω (Apply battery voltage to terminals 3l-6 and 3I-7)

Reinstall the integration relay.

NG: REPLACE INTEGRATION RELAY

Fig 2: Inspecting Integration Relay

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Go to next step

CHECK ECM (HT1B VOLTAGE)

Turn the power switch ON (IG).

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

Standard voltage

TESTER CONNECTION SPECIFIED CONDITION

Tester Connection	Specified Condition
E6-6 (HT1B) - E4-28 (E2)	9 to 14 V

OK: REPLACE ECM

Fig 3: Identifying ECM Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: Go to next step

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

Check the harness and the connectors between the ECM and the heated oxygen sensor connectors.

Disconnect the H13 heated oxygen sensor connector.

Fig 4: Identifying Heated Oxygen Sensor Connector
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Disconnect the E4 and E6 ECM connectors.

Measure the resistance according to the value(s) in the table below.

Standard resistance (Check for open)

TESTER CONNECTION SPECIFIED CONDITION

Tester Connection	Specified Condition
H13-1 (HT) - E6-6 (HT1B)	Below 1 Ω
H13-4 (E) - E4-28 (E2)	Below 1 Ω

Standard resistance (Check for short)

TESTER CONNECTION SPECIFIED CONDITION

Tester Connection	Specified Condition
H13-1 (HT) or E6-6 (HT1B) - Body ground	10 kΩ or higher
H13-1 (HT) - H13-2 (+B)	10 kΩ or higher

Fig 5: Disconnecting E4 And E6 ECM Connector

Reconnect the heated oxygen sensor connector.
Reconnect the ECM connectors.

Check the harness and the connectors between the heated oxygen sensor connector and the EFI M relay.

Disconnect the H13 heated oxygen sensor connector.
Remove the integration relay from the engine room relay block.

Measure the resistance according to the value(s) in the table below.

Standard resistance (Check for open)

TESTER CONNECTION SPECIFIED CONDITION

Tester Connection	Specified Condition
H13-2 (+B) - 3I-8 (EFI M relay)	Below 1 Ω

Standard resistance (Check for short)

TESTER CONNECTION SPECIFIED CONDITION

Tester Connection	Specified Condition
H13-2 (+B) or 3I-8 (EFI M relay) - Body ground	10 kΩ or higher

Reconnect the heated oxygen sensor connector.
Reinstall the integration relay.

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

Fig 6: Identifying Location Of Integration Relay From Engine Room Relay Block

OK: REPLACE ECM