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Check Engine Light On, Won't Flash Code

  1. Turn ignition off. Connect jumper to service check connector terminal. See Figure . Turn ignition on. If CHECK ENGINE light illuminates and flashes code(s), proceed to appropriate self-diagnostic trouble code. If CHECK ENGINE light does not illuminate, go to next step.
  2. Remove jumper from service check connector with ignition off. Try to start engine. If engine starts, go to step 3). If engine does not start, remove and inspect ECU fuse in underhood fuse/relay block. Replace if necessary. If fuse is okay, go to step 5).
  3. Using DVOM, measure voltage between service check connector Orange/Red (+) and Green/White (-) wires. If 5 volts are present, go to step 4). If 5 volts are not present, repair short to ground in Orange/Red wire between ECU terminal C4 and service check connector.
  4. Turn ignition off. Disconnect ECU connector "A". Turn ignition on. If CHECK ENGINE light illuminates, repair short in Green/Red wire between ECU terminal A13 and CHECK ENGINE light. If CHECK ENGINE light does not illuminate, substitute a known good ECU, and recheck. If condition is corrected, replace original ECU.
  5. Check fuse No. 2 in fuse/relay block behind left side of dash. Replace if necessary. If fuse is okay, turn ignition on. Disconnect 3-wire connectors to MAP, TPS and EGR lift sensors. If CHECK ENGINE light illuminates, go to step 6). If CHECK ENGINE LIGHT does not illuminate, replace sensor causing light to illuminate.
  6. Turn ignition off. Connect ECU Test Harness (07LAJ-PT3010A ). Disconnect ECU "D" connector (not wire harness). Check continuity between terminals D19 and D20 to ground. If continuity exists, repair short in Yellow/White wire between ECU terminals D19 and D20 to TPS, MAP or EGR lift sensor. If continuity does not exist, go to next step.
  7. Reconnect all connectors. Reconnect ECU connector "D". Turn ignition on. Individually connect terminals A26 and B2 to ground. If CHECK ENGINE light still stays on after 2 seconds, go to step 8). If CHECK ENGINE light turns off after 2 seconds, repair open in Black/Red wire between ECU terminal A26 and ground or in Brown/Black wire between ECU terminal B2 and ground.
  8. Measure voltage between ECU terminals A26 (-) to B1 (+) and A25 (+). If battery voltage is present, substitute a known good ECU, and recheck. If symptoms go away, replace original ECU. If battery voltage is not present, repair open in Yellow/Black wire between ECU terminals A25 and B1 to main relay. If wire is okay, check main relay and wiring connectors at main relay.
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