On-Board Diagnostics: Monitors

2004 Oldsmobile Bravada RWDSECTION Monitors
WARNING: This page is about a different car, the 2003 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.

  1. Comprehensive Component Monitor

    Monitors PCM systems for opens, shorts, grounds and out-of-range sensors. Also monitors rationality of sensors. Rationality is whether the sensor's value is consistent with operating conditions of the other sensors.
  2. Misfire Monitor

    Monitors engine misfire using crankshaft sensor to determine location and severity of misfire. A catalyst damaging misfire will flash the MIL, and a non-catalyst damaging misfire is a normal Type "B" code.
  3. Fuel Trim Monitor

    Monitors short and long term fuel trim for being at maximum lean or rich limit.
  4. Oxygen Sensor Monitor

    Monitors all oxygen sensors for maximum voltage level, minimum voltage level and lean rich/rich lean switching rate.
  5. Oxygen Sensor Heater Monitor

    Monitors oxygen sensor heater by watching sensor's time-to-activity after a cold start.
  6. Catalyst Monitor

    Monitors catalyst efficiency by comparing activity rate of pre-catalyst oxygen sensor and post-catalyst oxygen sensor.
  7. EVAP Monitor

    Monitors EVAP system for large leaks, small leaks and purge flow.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.