1994 Nissan-Datsun Sentra SE-R, AutomaticFACTORY OEM SERVICE PROCEDURE

ECM Power & Ground Circuits

  1. Start engine. If engine is running, go to next step. If engine will not start, turn ignition on. Measure voltage between ground and ECM harness connector terminal No. 36 (Black/Yellow wire).Battery voltage should be present. If battery voltage is present, go to step 7). If battery voltage is not present, repair open in Black/Yellow wire (1.6L) or Black/Red wire (2.0L) between ECM harness connector and ignition switch.
  2. Turn ignition off. Measure voltage between ground and ECM harness connector terminals No. 46 (White wire) and No. 109 (Orange/Blue wire). Battery voltage should be present. If battery voltage is present, go to next step. If battery voltage is not present, check harness and connectors between ECM and battery. Check 25-amp fusible link.
  3. Turn ignition on and off while measuring voltage between ground and ECM harness connector terminals No. 38 (Orange/Blue wire) and No. 47 (Orange/Blue wire). With ignition on and for a few seconds after turning ignition off, battery voltage should be present. A few seconds after turning ignition off, approximately zero volts should be present. If voltage is as specified, go to step 7). If battery voltage exists for more than a few seconds, check ECM relay. ECM relay is located next to ECM. See RELAYS  under RELAYS & SOLENOIDS.
  4. If battery voltage does not exist for a few seconds, disconnect ECM harness connector. Disconnect ECM relay. Check continuity between ECM harness connector terminals No. 38 (Orange/Blue wire) and No. 47 (Orange/Blue wire) and ECM relay harness connector terminal No. 5 (Orange/Blue wire). See Figure . Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Orange/Blue wire.
  5. Measure voltage between ground and ECM relay harness connector terminals No. 1 (White wire) and No. 3 (White wire). See Figure . Battery voltage should exist. If battery voltage exists, go to next step. If battery voltage does not exist, check harness and connectors.
  6. Check continuity between ECM harness connector terminal No. 4 (White/Green wire) and ECM relay harness connector terminal No. 2 (White/Green wire). See Figure . Continuity should exist. If continuity exists. check ECM relay. See RELAYS  under RELAYS & SOLENOIDS. If relay is okay, go to next step. If continuity does not exist, repair harness or connectors.
  7. Turn ignition off. With ECM harness connector disconnected, check continuity between ground and ECM harness connector terminals No. 6, 13, 39, 48, 107, 108 and 116 (all wires are Black). Continuity should exist. If continuity exists, check ECM pin terminals and ECM harness connector terminals for damage or corrosion. If continuity does not exist, repair harness or connectors.
Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.

Shop Manual-Ready ToolsCompare Repair QuoteQuote Shield Pro

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.

Rather have a pro handle this?

A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.

Comes to youSame-day available12-month warranty
Get a Free Quote

No obligation. See pricing before you book.