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Home >> Cadillac >> 1998 >> Seville SLS >> 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 POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK , then 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 DTCs are present, diagnose affected DTC(s) first. If DTCs are not present, go to next step.
  3. Turn ignition off. Wait 30 seconds then turn ignition on, with engine off. Using scan tool, record snapshot information for DTC P1350. Clear DTC P1350. After clearing DTC, start engine. Check if DTC P1350 fails in this ignition cycle. If DTC fails, go to next step. If DTC does not fail in this ignition cycle, fault is not present. See DIAGNOSTIC AIDS.
  4. Store fluid life index as indicated on scan tool. Turn ignition off. Wait 30 seconds then disconnect PCM harness connector C2 and IC module connector C4. Using DVOM, check for high resistance, short to ground or short to voltage in by-pass and ignition control circuit. Repair as necessary. If circuits are okay, go to next step.
  5. Turn ignition off. Reconnect PCM harness connector. Turn ignition on, but do not crank engine. Using DVOM, check voltage between ground and by-pass circuit, and between ground and ignition control circuit. If voltage reading is less than 1.0 volt, go to next step. If voltage reading is not less than 1.0 volt, go to step 11).
  6. Turn ignition off. Wait 30 seconds then 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 and operate engine at idle. Check voltage to ground on ignition control circuit from PCM. If voltage is fixed at about 1.7 volts, go to next step. If voltage is not fixed at about 1.7 volts, go to step 11).

  7. Check voltage to ground on by-pass circuit from PCM. If voltage is less than 1.0 volt, go to next step. If voltage is not less than 1.0 volt, go to step 11).
  8. Momentarily ground ignition control circuit. Check voltage to ground in by-pass circuit from PCM. If voltage reading is 4.7 volts or greater, go to step 9). If voltage reading is not 4.7 volts or greater, go to step 11).
  9. Check terminal contact at IC module harness connector C4. Repair as necessary. If terminal is okay, go to next step.
  10. Replace IC module.
  11. Check terminal contact at PCM harness connector C2. Repair as necessary. If terminal contacts are okay, go to next step.
  12. Replace PCM. Program replacement PCM using required equipment.
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