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Home >> Cadillac >> 1996 >> Eldorado Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Tests W/Codes >> Diagnostic Trouble Codes >> DTC P1350 - Ignition Control (Ic) System >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) System Check. After performing OBD system check, go to next step.
  2. Turn ignition on. Using scan tool, check if DTC P0322, P0372, P1323, P1371 or P1376 is also present. If any of these DTC(s) are present, diagnose affected DTC(s) first. If DTC(s) are not present, go to next step.
  3. Using scan tool, select DTC and select FAILURE REC and note ENGINE SPEED snapshot display for DTC P1350. If engine speed display reads less than 500 RPM, go to next step. If engine speed display reads greater than 500 RPM, go to step 9).
  4. Turn ignition off. Disconnect IC module harness connector C4. Using 6-Pin IC Module Diagnostic Jumpers, jumper the following IC module connector C4 terminals to the following module terminals:
    • C4 Terminal "A" To Module Pin "A"
    • C4 Terminal "B" To Module Pin "B"
    • C4 Terminal "C" To Module Pin "C"
    • C4 Terminal "D" To Module Pin "D"
    • C4 Terminal "E" To Module Pin "E"
    • C4 Terminal "F" To Module Pin "F"

    Turn ignition on. Using DVOM, check voltage between terminal "D" jumper and ground. If voltage is less than .4 volt, go to next step. If voltage is greater than .4 volt, go to step 7).

  5. Remove injector fuses from underhood fuse/relay block. Crank engine and check voltage on terminal "E" jumper. If voltage reading is 1.3 volts or greater, go to next step. If voltage reading is less than 1.3 volts, fault is not present. See DIAGNOSTIC AIDS.
  6. Store fluid life index as indicated on scan tool. Turn ignition off and wait 30 seconds, then disconnect PCM harness connector C2 and disconnect all jumpers from IC module connector. Check resistance of IC signal circuit between PCM harness connector and IC module harness connector terminals. If resistance is 5 ohms or less, go to step 25). If resistance is greater than 5 ohms, go to step 19).
  7. Store fluid life index as indicated on scan tool. Turn ignition off and wait 30 seconds, then disconnect PCM harness connector C2. Turn ignition on. Using DVOM, check voltage reading. If voltage is .4 volt or less, go to next step. If voltage reading is greater than .4 volt, go to step 27).
  8. Turn ignition off. Disconnect all jumper wires, but leave IC module harness connector C4 disconnected. Turn ignition on. Check voltage between ground and by-pass circuit at PCM harness connector terminal. If voltage reading is .4 volt or greater, go to step 20). If voltage reading is less than .4 volt, go to step 25).
  9. Turn ignition off. Disconnect IC module harness connector C4. Using 6-Pin IC Module Diagnostic Jumpers, jumper the following IC module connector C4 terminals to the following module terminals:
    • C4 Terminal "A" To Module Pin "A"
    • C4 Terminal "B" To Module Pin "B"
    • C4 Terminal "C" To Module Pin "C"
    • C4 Terminal "D" To Module Pin "D"
    • C4 Terminal "E" To Module Pin "E"
    • C4 Terminal "F" To Module Pin "F"

    Start engine. Using DVOM, check voltage between terminal "D" jumper and ground. If voltage reading is 4.1 volts or greater, go to next step. If voltage reading is less than 4.1 volts, go to step 17).

  10. Turn ignition off. Remove all jumper connectors, leaving IC module harness connector disconnected. Disconnect PCM harness connector C2. Using DVOM, check by-pass circuit between IC module connector and PCM connector terminals. If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, go to step 21).
  11. Reconnect PCM harness connector C2 and IC module harness connector jumpers. Set DVOM to 4-volt scale and push the Hz button. Start engine. Connect DVOM between jumper "E" terminal and ground. Frequency reading should be 30-100 Hertz. If frequency is as specified, fault is not present. See DIAGNOSTIC AIDS. If frequency is as specified, go to next step.
  12. Set DVOM to DC voltage scale.With engine running check voltage at jumper "E" terminal and ground. If voltage reading is 4 volts or less, go to next step. If voltage reading is greater than 4 volts, go to step 15).
  13. Turn ignition off. Disconnect jumpers from IC module harness connector C4. Set DVOM to PEAK MIN/MAX setting. Turn ignition on. Check voltage between ground and ignition control circuit at IC module harness connector C4 terminal. If voltage reading is 3.7 volts or less, go to next step. If voltage reading is greater than 3.7 volts, go to step 25).
  14. Turn ignition off. Disconnect PCM harness connector C2. Check resistance between ground and ignition control circuit at IC module harness connector terminal. If resistance is 10,000 ohms or less, go to step 22). If resistance is greater than 10,000 ohms, go to step 27).
  15. Turn ignition off. Disconnect jumpers from IC module harness connect C4. Turn ignition on. Check voltage between ground and ignition control circuit at IC module harness connector C4 terminal. If voltage reading is 1.3 volts or less, go to step 25). If voltage reading is greater than 1.3 volts, go to next step.
  16. Turn ignition off. Disconnect PCM harness connector C2. Turn ignition on. Check voltage between ground and ignition control circuit at IC module harness connector C4. If voltage is greater than .5 volt, go to step 23). If voltage is less than .5 volt, go to step 27).
  17. Turn ignition off. Disconnect jumpers from IC module harness connector. Disconnect PCM harness connector C2. Check resistance between ground and by-pass signal circuit at PCM harness connector terminal. If resistance is less than 5000 ohms, go to step 24). If resistance is greater than 5000 ohms, go to next step.
  18. Reconnect PCM harness connector C2. Reconnect all jumper wires at IC module harness connector C4. Turn ignition on. Clear all DTC(s). Turn ignition off. Disconnect EGR harness connector. Jumper EGR harness connector terminal "D" (5-volt reference) to IC module harness connector C4 jumper "D" terminal. Start engine. Check if DTC P1350 resets. If DTC resets, go to step 27). If DTC does not reset, go to step 25).
  19. Repair open in ignition control circuit.
  20. Repair short to voltage in bypass signal circuit.
  21. Repair open in by-pass signal circuit.
  22. Repair short to ground in ignition control circuit.
  23. Repair short to voltage in ignition control circuit.
  24. Repair short to ground in by-pass signal circuit.
  25. Check terminal contact at IC module harness connector C4. Repair as necessary. If terminal is okay, go to next step.
  26. Replace IC module.
  27. Check terminal contact at PCM harness connector C2. Repair as necessary. If terminal contacts are okay, go to next step.
  28. Replace PCM. Program replacement PCM using required equipment.
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