When Monitored

This diagnostic runs one time during an ignition cycle when the following conditions are met:

• With the ignition on.
• ASD Relay is commanded on.
• No active Fuel Rail Pressure circuit faults.
• Vehicle is in Fuel Delivery mode of operation.
• Fuel Pump commanded duty cycle is above 10%.
• Engine speed is greater than 300 rpm.
  • At initial engine start up, the PCM runs a Fuel Rail Pressure Sensor rationality check. For approximately the first 10.0 seconds, the fuel pressure is dynamic. At this time, It will spike above the set point (approximately 5.8-7.25 psi), then drop below the set point (approximately 8.7-10.2 psi), and quickly dampen and settle at the set point (approximately 75.0 psi). At initial engine start up, when the engine speed reaches approximately 500 rpm, the Powertrain Control Module (PCM) measures the delta pressure change between the high pressure reading and low pressure reading and make determinations about sensor rationality.