Test NS-7A - Checking DRB Communication

1994 Plymouth Laser RS Turbo, AWD, AutomaticSECTION Test NS-7A - Checking DRB Communication
NOTE: For connector terminal identification, see CONNECTOR IDENTIFICATIONΒ . For appropriate wiring diagram, see WIRING DIAGRAMSΒ .
  1. If DRB display is not blank, go to step 5). If DRB display is blank, disconnect DRB adapter from diagnostic connector. Turn ignition off. Measure resistance between diagnostic connector terminal No. 12 (Black wire) and ground. If resistance is less than 10 ohms, go to next step. If resistance is more than 10 ohms, repair open circuit in Black wire to ground. Perform TEST VER-1Β .
  2. Inspect DRB adapter Red battery lead for good connection to power. If adapter Red battery lead does not have good connection, repair as necessary. Perform TEST VER-1. If adapter Red battery lead has good connection, go to next step.
  3. Connect a known good DRB adapter to vehicle diagnostic connector. Reconnect DRB to adapter. If DRB display is blank, go to next step. If DRB display is not blank, perform TEST NS-1AΒ .
  4. Connect a known good DRB to adapter on vehicle. If DRB display is not blank, perform TEST NS-1A. If DRB display is blank, insert a known good cartridge into DRB. If DRB display is operational, perform TEST NS-1A. If DRB is not operational, repeat steps 1)-4).
  5. Using voltmeter, backprobe ECU 10-pin connector terminal No. 110 (Black/White wire). Turn ignition on. If voltage is more than 10 volts, go to next step. If voltage is less than 10 volts, repair open circuit in Black/White wire between ECU 10-pin connector and ignition splice. Perform TEST VER-1.
  6. Disconnect DRB adapter from diagnostic connector. Turn ignition off. Disconnect ECU 24-pin connector. Measure resistance of Yellow wire between ECU 24-pin connector terminal No. 1 and diagnostic connector terminal No. 5. If resistance is less than 10 ohms, go to next step. If resistance is more than 10 ohms, repair open circuit in Yellow wire. Perform TEST VER-1.
  7. Measure resistance between ECU 24-pin connector terminal No. 1 (Yellow wire) and ground. If resistance is more than 10 ohms, go to next step. If resistance is less than 10 ohms, repair Yellow wire for short to ground. Perform TEST VER-1.
  8. Measure resistance of White wire between ECU 24-pin connector terminal No. 2 and diagnostic connector terminal No. 1. If resistance is less than 10 ohms, go to next step. If resistance is more than 10 ohms, repair open circuit in White wire. Perform TEST VER-1.
  9. Measure resistance between ECU 24-pin connector terminal No. 2 (White wire) and ground. If resistance is more than 10 ohms, go to next step. If resistance is less than 10 ohms, repair White wire for short to ground. Perform TEST VER-1Β .
  10. Connect a known good DRB adapter to vehicle diagnostic connector. Using DRB, attempt to read faults. If DRB is not able to read faults, go to next step. If DRB is able to read faults, perform TEST NS-1AΒ .
  11. Insert a known good cartridge into DRB. Using DRB, attempt to read faults. If DRB is able to read faults, perform TEST NS-1A. If DRB is not able to read faults, replace ECU. Perform TEST VER-1.
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When to See a Mechanic

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

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