Preliminary Checks

Before using this section you should have already performed the "DTC P0030 Upstream Heated Oxygen Sensor Bank 1 Heater Resistance Out of Limits:"

Perform a thorough visual inspection. This inspection can often lead to correcting a problem without further checks and can save valuable time. Inspect for the following conditions:

• Engine Control Module (ECM) grounds for being clean, tight, and in their proper location.
• Vacuum hoses for splits, kinks, collapsing and proper connections as shown on the Vehicle Emission Control Information label. Inspect thoroughly for any type of leak or restriction.
• Air leaks at the throttle body mounting area and the intake manifold sealing surfaces.
• Ignition wires for cracks, hardness, proper routing, and carbon tracking.
• Wiring for proper connections.
• Wiring for pinches or cuts.