2001 Infiniti QX4 4WDFACTORY OEM SERVICE PROCEDURE

Ignition Signal Circuits: Altima

  1. Turn ignition off. Attempt to start engine. If engine is running, go to next step. If engine is not running, go to step  3.
  2. Let engine idle. Connect an oscilloscope between ground and ECM terminal No. 1 (White/Black wire) by backprobing. See Figure and Figure . Compare waveform to waveform shown in PIN VOLTAGE CHARTS article. If waveform is the same, test is complete. If waveform is not the same, go to step  5.
  3. Turn ignition off. Disconnect distributor 2-pin harness connector (ignition coil connector). Turn ignition on. Measure voltage between ground and ignition coil harness connector terminal No. 7 (Black/Red wire). If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit. See WIRING DIAGRAMS article.
  4. Turn ignition off. Disconnect distributor 6-pin harness connector. Check continuity between ground and distributor 6-pin harness connector terminal No. 2 (Black wire). See Fig 1. Continuity should exist. Also, check circuit for short to voltage. Repair circuit as necessary. If circuit is okay, go to next step.
  5. Turn ignition off. Disconnect ECM and distributor 6-pin harness connectors. Check continuity of White/Black wire between distributor 6-pin harness connector terminal No. 1 and ECM harness connector terminal No. 1. Also, check circuit for short to ground and short to voltage. Repair circuit as necessary. If circuit is okay, go to next step.
  6. Check ignition coil and power transistor. See IGNITION COIL  and POWER TRANSISTOR  . If ignition coil and power transistor are okay, go to next step. If ignition coil and power transistor are not okay, replace distributor assembly.
  7. Turn ignition off. Disconnect distributor 2-pin harness connector (ignition coil connector). Remove tape covering resistor located on engine control harness, near distributor. Disconnect resistor harness connector. Check continuity of Green wire between resistor harness connector terminal No. 1 and distributor 2-pin harness connector terminal No. 8. Check continuity of Orange/Black wire between resistor harness connector terminal No. 2 and ECM harness connector terminal No. 2. Also, check circuits for short to ground and short to voltage. Repair circuit(s) as necessary. If both circuits are okay, go to next step.
  8. Measure resistance between resistor connector terminals (component side). Resistance should be about 2200 ohms at 77°F (25°C). If resistance is as specified, go to next step. If resistance is not as specified, replace resistor.
  9. No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
Fig 1: Identifying Distributor 6-Pin Harness Connector Terminals
G96D10366Courtesy of NISSAN MOTOR CO., U.S.A.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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