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Chart A-2 ("C", "G", "K", "L", "M", "S" & "T" W/Gas Engine)

  1. Turn ignition on, but leave engine off. If MIL lamp is off, go to CHART A-1. If MIL lamp is on, ground diagnostic connector. If MIL lamp does not flash code DTC-12, go to next step. If MIL lamp flashes code DTC-12, check serial data circuit for shorts or opens. If circuit is okay, PCM or PROM may be faulty.
  2. If MIL lamp is off from step 1), turn ignition off. Disconnect PCM connectors. Turn ignition on. If MIL lamp goes on, check for short in circuit from MIL bulb to PCM connector.
  3. If MIL lamp stays off, turn ignition off. Reconnect PCM connectors. Turn ignition on, but leave engine off. Make sure diagnostic connector is not grounded. Using a test light, back probe diagnostic connector terminal "B" at PCM (Black/White or White/Black wire).
  4. If MIL lamp does not flash DTC-12, go to next step. If MIL lamp flashes DTC-12, check circuit (Black/White or White/Black wire) between diagnostic connector terminal "B" and PCM connector for short to ground.
  5. If MIL lamp does not flash DTC-12 from step 4), check PROM installation. If PROM is installed correctly, replace PCM using original PROM. If code DTC-12 is now present, system is okay. If code DTC-12 is still not present, replace PROM.
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