At idle with engine warmed up, MAP should read 0.8-1.4V indicating intake vacuum of 16-20 inHg. Key-on-engine-off should read approximately 4.5V (atmospheric pressure at sea level). Under wide-open throttle with turbo boost, voltage rises to 3.8-4.7V representing 15-20 psi boost pressure. Signal should show rhythmic pulsations at idle frequency corresponding to intake valve events, indicating good sensor response time.

At idle, MAF output should read 1.2-1.8V (approximately 3-6 g/s airflow). Under acceleration, voltage should rise smoothly without steps or dropouts to 3.5-4.5V at higher RPM and load. Signal should be clean with less than 50mV ripple; any sudden steps or glitches indicate contamination or failing hot-wire element. Voltage should correlate directly with calculated load displayed on scan tool.

Clean square wave with rapid voltage drop from 12V to near 0V when ECM grounds the injector, holding at ground for pulse width duration (2-4ms at idle, increasing with load). When injector closes, inductive kickback spike reaches 55-70V for 0.2-0.5ms before settling back to 12V. Consistent pulse width across all four injectors indicates balanced fuel trim.

Clean square wave showing 2-4ms dwell time at idle increasing with RPM. Primary voltage rises sharply to battery voltage during dwell, then drops rapidly to trigger secondary. Inductive kickback spike should be clean and consistent around 250V, clamped by the ignition driver module. All four cylinders should show identical patterns.

Initial firing spike reaches 15-25kV for a healthy combustion chamber with proper compression and fuel mixture. Spark line should be relatively flat at 3-5kV for 1.5-2ms burn time, followed by clean dampening oscillations. Higher firing voltage indicates increased secondary resistance from worn plugs or lean conditions.

Post-catalyst narrowband sensor should show stable voltage centered around 0.65-0.75V with minimal activity (less than 0.1V fluctuation) during steady-state cruise. A healthy catalyst dampens upstream switching so this sensor should remain relatively flat. During snap throttle, may see slow voltage drop to 0.3-0.4V then slow recovery over 10-15 seconds. Voltage should NOT mirror upstream sensor activity - this indicates catalyst failure.

Wideband AFR sensor maintains steady voltage around 3.0-3.1V at idle and cruise in closed loop. During snap throttle acceleration, voltage should drop quickly to 2.6-2.8V (indicating rich mixture) then return to 3.0V within 2-3 seconds. During deceleration fuel cut, voltage should spike to 3.5-3.8V (lean/no fuel) then recover. Heater element should show 4-8 ohms resistance and draw 0.5-1.0A when active.

Digital square wave signal showing 6 distinct pulses per cam revolution with one reference pulse that is narrower than the others for ECM synchronization. Signal should transition cleanly between 0.3V and 4.7V with frequency of approximately 16.5 Hz at idle. The pattern should align predictably with crankshaft position sensor at a 2:1 ratio.

Clean digital square wave transitioning sharply between approximately 0.3V and 4.7V with 12 consistent pulses per crank revolution at idle (approximately 700 RPM). The pulse width should be uniform with no distortion, ringing, or voltage spikes on transitions. At idle, expect approximately 33 Hz frequency with 50% duty cycle.

Dual redundant linear voltage signals that move in opposite directions as throttle opens. At closed throttle (idle), TPS1 should read 0.6-0.8V while TPS2 reads 4.2-4.4V. At wide open throttle, TPS1 should reach 4.3-4.6V while TPS2 drops to 0.5-0.7V. Both sensors must show smooth linear transitions with no steps, flat spots, or noise during a slow throttle sweep from closed to open.

Clean square wave transitions with sharp rising and falling edges. At 25 mph, expect approximately 80-90 Hz frequency. All four sensors should show identical frequencies when driving straight, with amplitude consistently between 0.3V low and 4.5-5.0V high with no missing teeth or erratic pulses.

Clean square wave with crisp transitions between low (0.3-0.5V) and high (4.5-5.0V) states. At 30 mph, expect approximately 66 Hz frequency. Signal should be consistent with no missing pulses, and frequency should increase/decrease smoothly and proportionally with vehicle speed changes.

At cold start (68°F), expect approximately 2.3-2.8V. As engine warms to operating temperature (195°F), voltage should smoothly decline to 0.4-0.6V. Voltage should be stable with no erratic jumps or dropouts during warm-up phase.

At ambient temperature (68°F), expect 2.0-2.5V. Under boost or hot soak conditions, voltage decreases to 1.5-1.8V. Signal should be rock-steady with minimal noise, changing only gradually with temperature variations during driving.

2016 Honda Civic Waveform References

Airflow Sensors

Fuel System

Ignition System

Oxygen Sensors

Position Sensors

Speed Sensors

Temperature Sensors