Oxygen Sensor Relay: Testing and Inspection

2UZ-FE ENGINE CONTROL SYSTEM: A/F SENSOR HEATER RELAY:

ON-VEHICLE INSPECTION

1. DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL

NOTICE:
- Some systems need to be initialized after the cable is reconnected (Repair Instruction - Initialization).
- After the ignition switch is turned OFF, the navigation system requires approximately 90 seconds to record various types of memory and settings. As a result, after turning the ignition switch OFF, wait 90 seconds or more before disconnecting the cable from the negative (-) battery terminal.

2. REMOVE INTEGRATION RELAY (UNIT E)
(a) Remove the engine room relay block cover.

(b) Using a screwdriver, detach the 2 claws and disconnect the integration relay from the engine room relay block.

HINT: Tape the screwdriver tip before use.

(c) Disconnect the 3 connectors.
3. INSPECT INTEGRATION RELAY (A/F SENSOR HEATER RELAY)

NOTICE:
- Some relays are built into the integration relay (unit E). The integration relay cannot be disassembled. If there is a malfunction in the circuit of the integration relay, replace the integration relay.
- The internal circuit of the integration relay is as shown in the illustration below. Inspect the integration relay using the following procedures.

(a) Measure the resistance of the A/F fuse.
(1) Measure the resistance according to the value(s) in the table below.
Standard resistance:

If the result is not as specified, replace the A/F fuse.

(b) Measure the resistance of the A/F relay circuit.
(1) Measure the resistance according to the value(s) in the table below.
Standard resistance:

If the result is not as specified, replace the integration relay.
4. INSTALL INTEGRATION RELAY (UNIT E)
(a) Connect the 3 connectors.
(b) Install the integration relay to the engine room relay block.
(c) Install the engine room relay block cover.
5. CONNECT CABLE TO NEGATIVE BATTERY TERMINAL

NOTE: Some systems need to be initialized after the cable is reconnected (Repair Instruction - Initialization).