1991 Acura Legend Base, AutomaticFACTORY OEM SERVICE PROCEDURE

Code 16: Fuel Injector Circuit

NOTE: For wiring diagrams, see WIRING DIAGRAMS article in the ENGINE PERFORMANCE Section. For vacuum diagrams, see VACUUM DIAGRAMS article in the ENGINE PERFORMANCE Section.
  1. Turn ignition off. Remove ACG fuse in underdash fuse box for 10 seconds to reset ECU. Try to start engine. If engine starts, go to next step. If engine does not start, go to step 5).
  2. If engine starts, verify if CHECK ENGINE light is flashing. If light is not flashing, problem is intermittent. Check for poor and loose connections at injectors, injector resistor and round connectors C354 and C356 at right shock tower. Test drive, and check again.
  3. If CHECK ENGINE light flashes Code 16, check for clicking sound of each injector using a stethoscope with engine at idle. If injector(s) does not click, turn ignition off.
  4. Disconnect 2-pin injector connector from affected injector. Measure resistance between injector terminals. Resistance should be 1.5-2.5 ohms. If resistance is not 1.5-2.5 ohms, replace injector. If resistance is okay, go to step 6).
  5. If engine does not start, turn ignition off. Disconnect injector terminals. Check resistance of all injectors. If resistance value is not 1.5-2.5 ohms, replace injector(s).
  6. If resistance values are within specification, turn ignition on. Measure voltage between Red/Black wire of injector terminal and ground. If battery voltage is not present, go to step 8). If battery voltage is present, reconnect 2-pin injector connectors. Turn ignition off.
  7. Connect ECU test harness to ECU. See Figure . Turn ignition on. Check voltage at following terminals.
    • Injector No. 1 - A1 Brown (positive) and Black (negative)
    • Injector No. 2 - A3 Red (positive) and Black (negative)
    • Injector No. 3 - A5 Orange (positive) and Black (negative)
    • Injector No. 4 - A2 White/Blue (positive) and Black (negative)
    • Injector No. 5 - A4 Black/Red (positive) and Black (negative)
    • Injector No. 6 - A6 Yellow (positive) and Black (negative)

    If battery voltage is not present, repair open in wire between injector and A1, A3, A5, A2, A4 and A6. If battery voltage is present, substitute a known good ECU, and retest. If specified voltage is now present, replace original ECU.

  8. Turn ignition off. Disconnect 8-pin connector at injector resistor. Turn ignition on. Measure voltage between Yellow/Black wire terminal and ground. If battery voltage is not present, repair open in Yellow/Black wire between injector resistor and main relay.
  9. If battery voltage is present, replace injector resistor. If still no voltage is present, repair open in Red/Black wire between 2-pin connector and resistor.
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.