Diagnostic Aids

For any test that requires probing ECM or component harness connectors, use Connector Test Adapter Kit (J-35616-A). This will prevent damage to harness connector terminals. Check for the following conditions:

HO2S 2 pigtail or harness may be mispositioned and contacting exhaust system. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, corrosion or water intrusion.

An oxygen supply inside HO2S 2 is necessary for proper operation. This supply of oxygen is provided through HO2S 2 wiring harness. All HO2S 2 wires and connections should be inspected for breaks or contamination. Repair as necessary. Inspect for poor ECM to engine ground connection.

Check for fuel contamination. Water, even in small amounts can be delivered to fuel injectors. Water can cause a lean condition to be indicated. Excessive alcohol in fuel can also cause this condition.

Inspect for poor ECM to engine grounds. If fuel pressure is too low, this DTC may set. Check for lean injectors. Inspect for disconnected or damaged vacuum hoses and for vacuum leaks at intake manifold, throttle body and crankcase ventilation system.