Toyota Tundra Service Manual: A/f Sensor Heater Relay

On-vehicle Inspection

ON-VEHICLE INSPECTION

PROCEDURE

1. REMOVE INTEGRATION RELAY

2. INSPECT INTEGRATION RELAY (A/F)

NOTICE:

• Some relays are built into the integration relay. 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 sensor heater relay. (1) Measure the resistance according to the value(s) in the table below. Standard Resistance: Tester Connection Condition Specified Condition 1C-1 - 1A-4 When battery voltage is not applied to terminals 1A-2 and 1A-3 10 kΩ or higher When battery voltage is applied to terminals 1A-2 and 1A-3 Below 1 Ω If the result is not as specified, replace the integration relay.

3. INSTALL INTEGRATION RELAY