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Home >> Cadillac >> 1998 >> Catera >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Tests W/Codes >> Diagnostic Trouble Codes >> DTC P0201 - Injector No. 1 Control Circuit >> Diagnostic Procedures

Diagnostic Procedures

  1. Perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  , then go to next step.
  2. Start and idle engine. Using scan tool, monitor misfire current cylinder No. 1. If counter is increasing, go to next step. If counter is not increasing, see DIAGNOSTIC AIDS.
  3. Turn ignition off. Disconnect main fuel injector connector. Turn ignition on, with engine off. Using test light connected to battery voltage, probe injector No. 1 harness connector control circuit (ECM side). If test light is on, go to next step. If test light is off, go to step 6).
  4. Turn ignition off. Disconnect ECM harness connector located in engine compartment relay center. If test light is on, go to step 11). If test light is off, go to next step.
  5. Turn ignition on, with engine off. Using test light connected to ground, probe injector No. 1 harness connector control circuit (ECM side). If test light is on, go to step 12). If test light is off, go to step 15).
  6. Crank engine. If test light blinks about once per second, go to step 8). If test light does not blink about once per second, go to next step.
  7. Turn ignition off. Disconnect ECM harness connector located in engine compartment relay center. Using DVOM, check harness continuity of injector No. 1 control circuit between main injector and ECM harness connectors. If continuity is present, go to step 14). If continuity is not present, go to step 10).
  8. Turn ignition off. Using a jumper wire, reconnect switched battery feed circuit in male half of main injector harness connector to switched battery feed circuit in female half of main injector harness connector. Using test light connected to ground, probe injector No. 1 harness connector control circuit (injector side). Turn ignition on, with engine off. If test light is on, go to step 13). If test light is off, go to next step.
  9. Check for poor connections and terminal tension at fuel injector harness connector or at main injector harness connector. Check injector control circuit for open, short to ground, or short to voltage between injector and main injector connector. Check for open in switched battery feed circuit between injector and wiring splice. Repair as necessary. After repairs are complete, go to step 16). If connections, terminals and circuits are okay, go to step 13).
  10. Repair open or high resistance in injector control circuit. After repairs, go to step 16).
  11. Repair short to ground in injector control circuit. After repairs, go to step 16).
  12. Repair short to voltage in injector driver circuit. After repairs, go to step 16).
  13. Replace fuel injector. After replacing injector, go to step 16).
  14. Check for poor connections and terminal tension at ECM harness connector. Repair as necessary. After repairs, go to step 16). If connections and terminals are okay, go to next step.
  15. Replace ECM. New ECM must be programmed with theft deterrent module frequency code currently on vehicle. After replacing ECM, go to next step.
  16. Using scan tool, clear DTCs. Turn ignition off for 15 seconds. Start engine and operate vehicle. Check for DTCs. If DTC P0201 is set, go to step 2). If DTC P0201 is not set, go to next step.
  17. If other DTCs were present during OBD system check and have not been diagnosed, go to applicable DTC. If no other DTCs are present, system is okay.
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