Diagnostic Test

2010 Jeep Grand Cherokee Limited, 5.7 T, 4WDSECTION Diagnostic Test
  1. CHECK FOR ACTIVE DTC 
    1. Turn the ignition on.
    2. With the scan tool, read the active DTCs.

      Does the scan tool display this DTC as active?

      Yes 

      • Go to step  2

      No 

  2. STARTER RELAY 
    1. Turn the ignition off.
    2. Remove the Starter Relay.
    3. Turn the ignition on.
    4. With the scan tool, read the active FCM DTCs.

      Does the scan tool display this DTC as active?

      Yes 

      • Go to step  3

      No 

  3. (F26) IGNITION SWITCH OUTPUT (START) CIRCUIT SHORTED TO GROUND 
    Fig 1: Checking Ignition Switch Output (Start) Circuit For Short To Ground
    GC0120154Courtesy of CHRYSLER LLC
    1. Turn the ignition off.
    2. Disconnect the FCM C1 harness connector.
    3. Measure the resistance between ground and the (F26) Ignition Switch Output (Start) circuit at the FCM C1 harness connector.

      Is the resistance below 100.0 Ohms?

      Yes 

      No 

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.