U2016

Signal Link Short to Ground (Non SCP) / From NGV Module

Network / Communication Network/Communication Module communication short 🟢 Low — Fix at next service ✅ Safe to Drive
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What This Actually Means

In plain language — no jargon

A wire or connector between your engine computer and the natural gas vehicle (NGV) module has a short circuit to ground, like a damaged electrical cable touching metal. The ECU can't communicate properly with the NGV system because the signal is being lost to ground.

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Symptoms You May Notice

3 known symptoms for this code
Check Engine Light illuminated
NGV system inoperative or won't switch fuels
Communication errors between ECU and NGV module
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How Your ECU Detects This

Technical sensor logic and voltage thresholds

The ECU sends a diagnostic signal to the NGV module and monitors the response voltage on the signal line. When the line is shorted to ground, the voltage collapses to near 0V instead of the expected signal level, triggering a fault. The ECU detects this abnormal low-voltage condition and sets the code.

Voltage & Parameter Thresholds

ParameterNormal RangeFault Condition
Signal Line Voltage 4.5-5.5V (depending on signal type) <0.5V (shorted to ground)
Signal Resistance to Ground >10 kΩ <1 kΩ
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Diagnostic & DIY Fix Guide

Check these in order — from cheapest to most complex
1
Wire connectors and pins
Inspect the NGV module connector for corrosion, bent pins, or loose connections; reseat firmly and clean with electrical contact cleaner.
2
Signal wiring harness
Visually trace the signal wire from ECU to NGV module for cuts, abrasions, or exposed copper touching the engine block or frame.
3
NGV module connector pigtail
Replace the damaged signal wire or connector harness if insulation is compromised or pin damage is found.
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When to See a Professional Mechanic

Not all fault codes are safe to DIY

Code U2016 is a low-severity fault. Your vehicle is generally safe to drive to a workshop for diagnosis. However, do not ignore it indefinitely — low-severity codes often indicate developing problems that become expensive if neglected. Book a diagnostic appointment within 2–4 weeks. If you notice any additional symptoms (rough running, power loss, unusual smells), treat it as higher priority.

Safety note: OBD-II codes identify the system or circuit where a fault was detected — they do not always identify the exact failed component. A professional mechanic using live sensor data will diagnose the root cause more accurately than replacing parts based on the code alone.
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How to Clear Code U2016

What happens after you fix the fault

Once the fault is repaired, U2016 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.

The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.

✅ Safe to Clear When
  • Fault has been diagnosed and repaired
  • You want to confirm the repair worked
  • Code appeared after a sensor was cleaned
⚠️ Do Not Clear When
  • Preparing for an emissions/PUC test
  • Root cause is still undiagnosed
  • Check engine light is flashing
Emissions test note: Clearing codes resets OBD readiness monitors. Most vehicles need 50–100 km of mixed driving before monitors complete. Do not clear codes immediately before an emissions or PUC inspection.