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 RWDSECTION Monitors
WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. 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 sensors 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 precatalyst oxygen sensor and postcatalyst oxygen sensor. - EGR Monitor
Monitors operation and flow rate of EGR system. - EVAP Monitor
Monitors EVAP system for large leaks, small leaks and purge flow. - Secondary Air Monitor
Monitors secondary air operation.
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.