Action
The engine control relay connector terminal supplies power to the heater power terminal on the linear A/F sensor connector.
The power transistor in the engine-ECU connector termina
Capability
When the heater is activated, the engine ECU checks to see if the heater current is within a predetermined range.
Inconvenience Judgment
Check Conditions:
The electric motor switch’s power supply mode has already been ON for more than 2 seconds.
The auxiliary battery positive voltage is bigger than 11 V and less than 16.5 V while the linear A/F sensor heater is on.
Judgement Criterion: For two seconds, the linear A/F sensor heater current exceeds 10.5 A.
PROBABLE CAUSES
-Faulty linear A/F sensor heater
-Short circuit in linear A/F sensor heater circuit or loose connector contact broken wire
-Faulty engine-ECU
DIAGNOSIS CHECK
Check the linear A/F sensor itself for any damage, unplug the linear A/F sensor connector and measure the resistance between terminals 2 and 3 of the linear A/F sensor connector the standard value: 2.3 – 4.2 Ω at 20°C If the resistance out from the standard value, replace the linear A/F sensor.
Check the power supply line for short circuits. Check earthing line for short circuits. If the wire harness or connector is damaged repair or replace it.
For Intermittent malfunctions:
Cautiously shake or move the connector up, down and to the left and right.
Cautiously shake or move the wiring harness up, down and to the left and right.
Cautiously rock each sensor and relay, etc. by hand.
Cautiously shake or move the wiring harness at suspensions and other moving parts.
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