Circuit/System Testing

If the value is not less than 18%, inspect for the following:

• With the ignition ON and the engine OFF, observe the scan tool MAP Sensor parameter. The scan tool MAP Sensor pressure reading should be within the range specified for your altitude. Refer to Altitude Versus Barometric Pressure .
  • If the B74 Manifold Absolute Pressure Sensor does not indicate the correct barometric pressure, refer to DTC P0106 , DTC P0106 (LUV) , or DTC P0107 or P0108 .
• With the engine idling and the transmission in the park or neutral position, observe the scan tool MAP Sensor parameter. The scan tool MAP Sensor parameter should be between 19-42 kPa (2.8-6.1 PSI).
  • If the scan tool MAP sensor parameter is not between 19-42 kPa (2.8-6.1 PSI), refer to DTC P0106 , DTC P0106 (LUV) , or DTC P0107 or P0108 .
• Vacuum hoses for splits, kinks, and improper connections
• Insufficient amount of fuel in the tank
• Low fuel pressure-Refer to Fuel System Diagnosis .
• Fuel contamination-Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
• Malfunctioning fuel injectors-Refer to Fuel Injector Diagnosis .
• Missing, loose, or leaking exhaust components from the HO2S forward-Refer to Symptoms - Engine Exhaust .
• Vacuum leaks at the intake manifold, the throttle body, the brake booster hose, and the injector O-rings
• The air induction system and the air intake ducts for leaks or for a missing air filter element
• A cracked EVAP canister
• Evaporative pipes obstructed or leaking
• The crankcase ventilation system for leaks.
• The HO2S for improper installation and for electrical wires or connectors that may have contacted the exhaust system
• The B52A Heated Oxygen Sensor 1 sensor 1 signal circuit open, shorted to ground, or shorted to the low reference circuit
• The B52A Heated Oxygen Sensor 1 sensor 1 low signal circuit for an open circuit or high resistance
• Malfunctioning engine components-Refer to Symptoms - Engine Mechanical .

Repair or replace as necessary.