Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
On-Board Diagnostics: Monitors
2004 Oldsmobile Bravada AWDSECTION Monitors
WARNING: This page is about a different car, the 2003 Pontiac Grand Prix, 2003 Chevrolet Malibu, and 2003 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
- 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 value is consistent with the operating conditions of the other sensors.
- 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.
- Fuel Trim Monitor - Monitors short and long term fuel trim for being at maximum lean or rich limit.
- Oxygen Sensor Monitor - Monitors all oxygen sensors for maximum voltage level, minimum voltage level and lean rich/rich lean switching rate.
- Oxygen Sensor Heater Monitor - Monitors oxygen sensor heater by watching sensor's time-to-activity after a cold start.
- Catalyst Monitor - Monitors catalyst efficiency by comparing activity rate of pre-catalyst oxygen sensor and post-catalyst oxygen sensor.
- 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.