Ignition Switch (Key-On) Mode

2013 Chrysler Town & Country S, GasSECTION Ignition Switch (Key-On) Mode
WARNING: This page is about a different car, the 2013 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.

This is an Open Loop mode. When the fuel system is activated by the ignition switch, the following actions occur:

  • The PCM pre-positions the idle air control (IAC) motor.
  • The PCM determines atmospheric air pressure from the MAP sensor input to determine basic fuel strategy.
  • The PCM monitors the engine coolant temperature sensor input. The PCM modifies fuel strategy based on this input.
  • Intake manifold air temperature sensor input is monitored.
  • Throttle position sensor (TPS) is monitored.
  • The auto shutdown (ASD) relay is energized by the PCM for approximately three seconds.
  • The fuel pump is energized through the fuel pump relay by the PCM. The fuel pump will operate for approximately three seconds unless the engine is operating or the starter motor is engaged.
  • The O2S sensor heater element is energized via the ASD relay. The O2S sensor input is not used by the PCM to calibrate air-fuel ratio during this mode of operation.
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.