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HOMESERVICE MANUALSJEEP2008WRANGLER RUBICON, STANDARDREPAIR AND DIAGNOSISENGINE PERFORMANCETESTING & DIAGNOSISDTCS U1110 TO U1418, SYSTEM CHECKS, CHECKING POWER AND GROUND CIRCUITS, ENGINE CRANKS BUT NO START, INTERMITTENT NO CRANK CONDITION*CHECKING THE PCM POWER AND GROUND CIRCUITSDIAGNOSTIC TEST
2008 Jeep Wrangler Rubicon, Standard

Diagnostic Test

2008 Jeep Wrangler Rubicon, StandardSECTION Diagnostic Test
  1. PCM WIRING OR CONNECTORS 

    Turn the ignition off.

    Using the wiring diagram/schematic as a guide, inspect the wiring and each connector at the PCM.

    Look for any chafed, pierced, pinched, or partially broken wires.

    Look for broken, bent, pushed out or corroded terminals.

    Were any problems found? 

    Yes 

    1. Repair as necessary.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go To step  2.
  2. CHECKING THE PCM GROUND CIRCUITS 
    Fig 1: Using 12 Volt Test Light Connected To 12 Volts To Check PCM Ground Circuits
    GC0051020Courtesy of CHRYSLER LLC

    Turn the ignition off.

    CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

    Using a 12 volt test light connected to 12 volts, check the PCM ground circuits.

    Wiggle test each circuit during the test to check for an intermittent open in the circuit.

    NOTE: The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.

    Is the test light illuminated and bright? 

    Yes 

    1. Go To step  3.

    No 

    1. Repair the PCM ground circuit(s) for an open circuit or high resistance.
    2. Perform POWERTRAIN VERIFICATION TEST .
  3. CHECKING THE PCM FUSED IGNITION CIRCUITS 
    Fig 2: Checking PCM Fused Ignition Switch Circuits
    GC0003020Courtesy of CHRYSLER LLC
RENDER: 1.0x

NO RELATED

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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.