Turbo Dodge No Start Diagnostics

This is a common turbo Dodge no start diagnostics procedure that is frequently needed when your TD wont start! This is a pretty handy guide to reference to determine if it's fuel, or ignition related fault.

Pre-Diagnostics Checks

Before you begin performing these diagnostic tests, first check for any fault codes that may be present. If fault codes are present, clear them (battery disconnect) and crank the engine for 10 seconds and recheck codes. If codes are still present repair them before continuing.

PLEASE NOTE: These tests can also be run on 91 up(except T-3) but the DB/YL wire was removed from the diagnostic connector so you cannot actuate the ASD as it is listed in step #3.

Begin Diagnostics

1)The first step is to verify that there is no spark by removing the coil wire from the distributor cap and carefully holding it 1/4" from a good ground. It’s best to use an insulated tool for this task to avoid a high voltage shock.

  • Crank the engine for 7-10 seconds, spark should be strong and consistent
  • Count 1-2 sparks as No Spark.

Is there good spark present?

    Yes...then recheck the presence of spark at a spark plug, if spark is not present at the plugs the issue is with the secondary ignition(cap, rotor, wires)

    If there is good spark present then your issue is intermittent or is not ignition related, move to fuel system diagnostics.


2)Verify the following...

  • Distributor is turning when you crank the engine, if distributor is not turning repair timing belt issue.
  • Coil wire is not an open circuit, check the coil wire resistance with an ohmmeter. The standard measurement should be 3K-50K ohms per foot. Replace if the measurement is out of this range.

Are the distributor and coil wire OK?


3)Check ASD Relay circuit. (You should hear the fuel pump cycle for 1 second with initial key on)

  • Locate the under-hood diagnostic connector, it is located on the passenger shock tower.
  • With the key on/engine off ground the DB/YL(dark blue/yellow) wire. This will actuate the ASD relay.(A Code 42 will be set in memory)
  • Power (battery voltage) should be present at the + coil, DG/BK (dark green/black) wire at the injector(s) and at the fuel pump.
  • You should hear the fuel pump running.


Is power present?

    No...Repair ASD Relay circuit

4)Check the HEP (hall effect pickup) circuit.

  • First remove the ground wire from the diagnostic connector.
  • Using a 12 volt test lamp connected to + coil and ground crank the engine.
  • The test lamp should illuminate.

Did the test lamp illuminate?

    No...Repair the HEP circuit

5)Check coil control circuit

  • Using a 12 volt test lamp connected to - coil and ground crank the engine.
  • The test lamp should flash on/off repeatedly.
  • If the lamp flashed on/off but no spark...replace the ignition coil.
  • If the lamp did not light...replace the ignition coil
  • If the test lamp illuminated but did not the coil control circuit.