Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Code 16 - Fuel Injector Circuit
- Turn ignition off. Remove BACK-UP fuse (7.5-amp) from underhood fuse/relay box for 10 seconds to reset ECM. Retrieve codes. If Code 16 does not appear, problem is intermittent. Inspect poor connections at ECM, fuel injector, and wiring harness connectors. Test-drive vehicle and retest.
- If Code 16 appears, start engine. Listen for clicking sound at each injector. If injector does not click, turn ignition off. Unplug connector from affected injector. Measure resistance between injector terminals. Resistance should be 10-13 ohms. If resistance is okay, go to next step. If resistance is not 10-13 ohms, replace injector.
- Turn ignition on. Measure voltage between fuel injector harness Yellow/Black wire and ground. If battery voltage does not exist, repair open in Yellow/Black wire between fuel injector and main relay. If battery voltage exists, turn ignition off. Reconnect fuel injector connector.
- Connect ECM Test Harness (07LAJ-PT3010A
) between ECM and ECM harness. See Figure
. Turn ignition on. Measure voltage between A23 (-) and following test terminals.
- Injector No. 1: A1 (+)
- Injector No. 2: A3 (+)
- Injector No. 3: A5 (+)
- Injector No. 4: A2 (+)
If battery voltage does not exist, repair open in wire between injector and affected ECM connector terminal (A1, A2, A3, or A5). If battery voltage exists, temporarily substitute known good ECM, then retest system.
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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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