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. Warm up the engine to normal operating temperature (the radiator fan comes
on).
2. Apply the parking brake, and block both rear
wheels. Start the engine, then shift to the D position
while pressing the brake pedal. Press the
accelerator pedal, and release it suddenly. The
engine should not stal
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