Intermittent Failures
The term "intermittent failure" means a system may
have had a failure, but it checks OK now. If the
malfunction indicator lamp (MIL) on the dash does not
come on, check for poor
Electronic Control System
The functions of the fuel and emission control systems are managed by the
powertrain control module (PCM).
Self-diagnosis
The PCM detects a failure of a signal from a sensor
1. Apply the parking brake.
2. In cold weather, turn off all
electrical accessories to reduce
the drain on the battery.
3. Make sure the shift lever is in
Park. Press on the brake pedal.
4. Without touching the accelerator
pedal, turn the ignition key to the
START (III) position. Do not
Testing of Readiness Codes
If you take your vehicle for an
emissions test shortly after the
battery has been disconnected or
gone dead, it may not pass the test.
This is because of certain ‘‘readiness
codes’’ that must be set in the onboard
diagnostics for the emissions
systems