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Home >> Jeep >> 1996 >> Grand Cherokee Limited, 5.2 Y >> Repair and Diagnosis >> External Pages >> Different car >> Section 180 (Engine Controls - Tests W/Codes - 4.0L) >> Self-Diagnostic Tests >> Test NTC-2A - Checking Secondary Ignition & Timing

Test NTC-2A - Checking Secondary Ignition & Timing

WARNING: This page is about a different car, the 1995 Jeep Wrangler, 1995 Jeep Grand Cherokee, and 1995 Jeep Cherokee. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Perform TEST TC-1A  before proceeding with this test. For connector terminal identification, see CONNECTOR IDENTIFICATION  at beginning of article. For wiring diagrams, see WIRING DIAGRAMS  at the end of this article. Perform TEST VER-2A  after each repair.
  1. Turn engine off. Connect engine analyzer to engine. Start engine and let idle. If engine will not idle, maintain constant engine speed for reading scope pattern. Set scope to read display or parade pattern. Follow equipment manufacturer's procedure for pattern analysis.
  2. If secondary ignition pattern is not okay, repair indicated component in secondary ignition system. If secondary ignition pattern is okay, disconnect any spark plug wire. Observe secondary kilovolt line.
  3. If open circuit secondary voltage is not at least 25 kilovolts, replace electronic ignition coil. If open circuit secondary voltage is at least 25 kilovolts, reinstall spark plug wire.
  4. Ensure engine temperature is more than 180°F (82°C) before proceeding. Using scan tool, read total spark advance. Increase engine speed to 2000 RPM. If spark advance does not change with increase in RPM, replace Powertrain Control Module (PCM). If spark advance changes with increase in RPM, secondary ignition and timing advance are functioning properly. Test is complete.