Circuit/System Testing
WARNING: This page is about a different variant/trim than selected.
- Ignition - On/Vehicle - In Service Mode
- Verify the scan tool parameter: MAP Sensor = 20 to 48 kPa (2.9 to 7 PSI)
- If not in the specified range
- Go to next step: If in the specified range
- Verify the following conditions do not exist:
- Q17 Fuel Injector - Restricted - Refer to: Fuel System Diagnosis (except NPP) , or Fuel System Diagnosis (NPP)
- Q38 Throttle Body - Vacuum leak
- Exhaust System - Cracked/Leaking/Loose Clamps/Missing components/Restricted - Refer to: Symptoms - Engine Exhaust
- Fuel - Contaminated/Poor Quality - Refer to: Alcohol/Contaminants-in-Fuel Diagnosis
- Fuel injectors which do not close completely. - Refer to: Fuel Injector Diagnosis
- Ignition System = Malfunction - Refer to: Electronic Ignition System Diagnosis
- Intake Air Duct - Blocked/Collapsed/Loose Clamps/Visible Damage
- MAF Sensor = Contamination of the measuring element
- Mechanical Condition@Engine - Altered air flow
For example:
- Cylinder Head@Intake PortorExhaust Port - Restrictions/Casting Flash
- Intake Manifold - Restrictions/Casting Flash/Vacuum leak
- Intake ValveorExhaust Valve - Stuck/Leaking
- Lock Pin@Valve Rocker Switching Arm - Broken/Stuck
- Valve Rocker Switching Arm - Binding or Sticking/Mechanically stuck/Visible Damage/Worn
- Positive Crankcase Ventilation System - Leaking/Restricted - Refer to: Crankcase Ventilation System Inspection/Diagnosis
- Vacuum Hoses - Kinked/Leaking/Incorrect connection
- If a condition exists - Repair or replace as necessary
- Go to next step: If no condition exists
- Refer to: Symptoms - Engine Mechanical