Hint:
Use the table below to help determine the cause of the problem symptom. The potential causes of the symptoms are listed in order of probability in the "suspected area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.


Air-fuel ratio (a/f) and heated oxygen (ho2) sensor
heater monitors (front a/f and rear ho2 sensor type)
Terminals of ecmPower outlet socket
Components
Removal
Disconnect cable from negative battery
terminal
Caution:
Wait at least 90 seconds after disconnecting the
cable from the negative (-) battery terminal to
prevent airbag and seat belt pretensioner activation.
Remove switch base (see page ip-21)
Remove power o ...
Air-fuel ratio (a/f) and heated oxygen (ho2) sensor
heater monitors (front a/f and rear ho2 sensor type)
Preconditions
The monitor will not run unless:
The mil is off.
Drive pattern
Connect the intelligent tester to the dlc3.
Turn the ignition switch on.
Turn the tester on.
Clear dtcs (if set) (see page es-35).
Start the engine.
Allow the engine to idle for 10 minute ...
Catalyst system efficiency below threshold (bank 1)
Monitor description
The ecm uses sensors mounted in front of and behind the three-way catalytic
converter (twc) to
monitor its efficiency.
The first sensor, the air-fuel ratio (a/f) sensor, sends pre-catalyst
information to the ecm. The second
sensor, the heated oxygen (ho2) sensor, se ...