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Home >> Jeep >> 2021 >> Gladiator Mojave, Part Time T/Case Control, Automatic Trans >> Repair and Diagnosis >> External Pages >> Different car >> Section 49 (Starting System - Non-DTC Based Diagnostics) >> Diagnosis And Testing >> No Crank (BCM Equipped) >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different car, the 2022 Chrysler Voyager and 2022 Chrysler Pacifica. However, it is still accessible from the selected car via links, so may be relevant.
  1. STARTER RELAY CHECK 
    1. When attempting to start the vehicle, listen and if needed feel for a click at the starter relay in the PDC.
      NOTE:

      Some starter relays are internal to a module and may not be accessible, making it more difficult to hear, or feel the clicking response. It is possible for a poor ground or the Trans Range Sensor position to be lost causing the starter to click once.

      Did you hear an audible click at the relay or starter?

      Yes 

      • Go To  9

      No 

      • Go To  2
  2. STARTER RELAY INPUT CHECK 
    1. Use a 12 volt test light/DVOM to check for power at pin 85 of the starter relay.

      Is there Power/12 volts at pin 85?

      Yes 

      • Go To  8

      No 

      • Go To  3
  3. RF HUB OPERATION 
    1. Using the scan tool, confirm the ignition switch status changes in the RF HUB under the data display screen for the "Sensor" values.

      Does the ignition switch status on the data screen match the physical position of the KIN/IGNM?

      Yes 

      • Go To  5

      No 

      • Go To  4
  4. REMOTE START ANTENNA 
    NOTE:

    If the vehicle is not equipped with Remote Start, proceed to the next test step.

    1. Cycle the ignition off.
    2. Disconnect the Remote Start Antenna from the RF HUB.
    3. Using one FOBIK and sitting in the driver's seat, attempt to start the vehicle.

      Did the vehicle start?

      Yes 

      • Replace the Remote Start Antenna in accordance with the Service Information.
      • Perform the BODY VERIFICATION TEST .

      No 

      • Go To  5
  5. BCM IGNITION STATUS 
    1. Using the scan tool, confirm the ignition switch status changes in the BCM under the data display screen for the "Bussed Input" and "Sensor" values.
      NOTE:

      The change of status in the BCM for the "Sensor" value validates the voltage activity (with very low amperage) of the F20 circuit.

      In the BCM, do both values for the ignition switch status match; and do they match those in the RF HUB?

      Yes 

      • Go To  6

      No 

      • If the status of the Ignition Switch position is not changing under the "Sensor" value, check the F20 circuit at the BCM for battery voltage with a DVOM (not a test light).
      • If there is Battery voltage at the BCM on the F20 circuit  verify all power, ground and bus circuits are ok for the BCM. If no problem found replace the BCM in accordance with Service Information.
      • If there is NO  Battery voltage at the BCM  on the F20 circuit, then check for voltage on the F20 circuit at the RF HUB.
      • If there is Battery voltage coming out of the RF HUB on the F20 circuit  , check the F20 circuit between the RF HUB and BCM for a short, open condition or high resistance.
      • If there is NO  Battery voltage coming out of the RF HUB on the F20 circuit  verify all power, ground & communication circuits, & connections to the RF HUB prior to replacing.
      • In the data screen, if the status of the Ignition Switch was not changing under the "Bussed Input" value, further diagnosis is needed between the RF HUB, (bus circuits, connections) and the BCM.
  6. PCM IGNITION, TRANS RANGE/CLUTCH SWITCH STATUS VERIFICATION 
    1. Using the scan tool confirm there are no inhibits that have been triggered in the PCM (i.e. Ignition Switch, Trans Range or Clutch Switch) and any switch inputs (filtered states) relating to the starting system function and operate correctly under the data display screen.

      Does the PCM show any inhibits (not DTCs  ) for starting (not remote starting  )?

      Yes 

      • Correct the inhibit reason listed.
      • If no problem can be found, then verify all power, ground and bus circuits to the PCM and replace the PCM in accordance with the Service Information.

      No 

      • Go To  7
  7. BCM TO STARTER RELAY POWER INPUT CHECK 
    1. At this time if all the correct inputs for the ignition switch status are correct in the RF HUB, BCM and PCM, verify both power feeds are present (pin 30 and 85) to the Starter Relay while in the crank position.

      Are both power feeds present at the relay when the ignition is in the crank position?

      Yes 

      • Go To  8

      No 

      • If, there is no power to pin 30 or 85, no DTCs, TSBs, Recalls, or Inhibits replace the BCM in accordance with Service Information.
  8. STARTER RELAY CONTROL CIRCUIT CHECK 
    1. Using a test light/DVOM determine if the Starter Control circuit at pin 86 of the relay is missing ground (at the relay if equipped with a removable relay or wiring to the internal relay) when the ignition is in the crank position.

      Was the Starter Control circuit for pin 86 being grounded when the ignition was in the crank position?

      Yes 

      • Go To  10

      No 

      • Verify the Starter Relay Control circuit from pin 86, has no shorts, opens or high resistance on the wiring going from the Starter Relay in the BCM (or PDC) to the PCM.
      • Verify the cables do not have excessive resistance by performing a voltage drop on the battery cables.
  9. STARTER RELAY OUTPUT CIRCUIT CHECK 
    NOTE:

    At this point in the test, when the key is in the crank position power has been verified at Pin 30 & 85, along with the control circuit being grounded for pin 86.

    1. Remove the Starter Relay Output circuit connector from the Starter solenoid.
    2. Using a test light/DVOM and ignition in the crank position check for power at pin 87 (If equipped with a removable relay or wiring to the internal relay) of the relay and at the connection to the starter.

      Was there power at pin 87 for the output circuit?

      Yes 

      • Go To  10

      No 

      • If power is missing to pin 30 of the starter relay the BCM is suspect. Verify all power, ground, communication circuits and connections to the BCM before replacing in accordance with service information.
      • If power is missing at pin 87 of the starter relay and the relay is replaceable, change out the relay and recheck the concern. If a known good relay causes no change, check the Starter Output circuit from pin 87 of the relay to the starter for an open, short, excessive resistance, or poor connections to the solenoid or starter.
      • Verify and Inspect the Starter to ensure it is free of corrosion, oil, and there is no damage, or binding conditions.
      • Verify that all wiring, cables and connections are clean and tight.
  10. STARTER RELAY OUTPUT CIRCUIT LOAD TEST 
    1. Load test the Starter Relay output circuit going from the BCM to the Starter.

      Does the starter relay output circuit pass the load test?

      Yes 

      • Verify that all connections are clean, tight and there is no damage to starter when fully inspected. If no problem found then replace the Starter in accordance with Service Information.

      No 

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