At idle, voltage should be stable at 1.0-1.5V indicating proper manifold vacuum (17-21 inHg). During snap throttle to WOT, voltage should rise smoothly to 4.5V (near atmospheric pressure). At faster timebase (10ms/div), distinct intake pulses should be visible showing individual cylinder intake strokes. Key-on-engine-off voltage should read approximately 4.5V (barometric pressure reference).

Smooth, stable DC voltage at idle between 1.0-1.3V with minimal fluctuation (less than 0.05V ripple). During snap throttle test, voltage should rise smoothly and proportionally to approximately 3.5-4.5V, then decay smoothly back to idle without steps, spikes, or dropouts. Response time should be immediate with no lag or hesitation.

Clean rectangular pulse starting at battery voltage, dropping instantly to near 0V during injector opening with pulse width of 2.5-4.5ms at warm idle. Sharp inductive kickback spike to 50-65V when ECM switches off, indicating proper pintle closure. All four injectors should show nearly identical pulse widths and timing patterns during steady-state idle.

Clean square wave switching with dwell time of 3-4ms at idle. Primary voltage rises instantly to battery voltage when transistor closes, then drops sharply to 0V when coil fires with a brief inductive spike visible. Pattern repeats every 48ms at idle (4-cylinder firing). Current limiting should show flat top at battery voltage during dwell.

Firing line should spike to 8-15kV (higher when cold), immediately followed by flat spark line at 2-3kV for approximately 1.5-2.5ms duration. Clean oscillating coil ringing follows spark extinction. Spark duration consistency across all four cylinders indicates healthy coils and uniform cylinder compression.

Traditional narrowband O2 sensor showing slow, lazy transitions with crossing frequency of 0.5-2 times per second during closed loop. Voltage should spend time at both rich (0.65-0.85V) and lean (0.15-0.35V) extremes with relatively flat tops and bottoms, indicating efficient catalyst oxygen storage. Transitions should be gradual, taking 200-500ms.

Air-fuel ratio sensor maintains steady voltage near 3.3V at stoichiometric (14.7:1) during closed loop operation with minimal variation (±0.15V). Voltage shifts smoothly and quickly to 2.7-2.9V during acceleration enrichment and 3.5-3.7V during deceleration lean conditions. Response time to forced rich/lean changes should be under 100ms.

Clean digital square wave switching between approximately 0.3V (low) and 4.7V (high) with sharp transitions. Pattern shows three distinct pulses of different widths per revolution for position identification. Frequency should be exactly half of crankshaft sensor frequency, confirming proper timing chain condition.

Clean AC sine wave pattern with consistent amplitude showing 34 evenly-spaced pulses followed by a gap where 2 teeth are missing. At idle (650-750 RPM), amplitude should be 4-6V peak-to-peak, increasing proportionally with engine speed. The missing tooth gap should be clearly visible and consistent.

Dual redundant sensors with inverse voltage relationship; at closed throttle TPS1 reads 0.65-0.85V while TPS2 reads 4.0-4.3V. As throttle opens to WOT, TPS1 rises smoothly to 4.2-4.6V while TPS2 drops smoothly to 0.5-0.8V. Voltage change should be perfectly smooth without steps, glitches, or dead spots through entire range.

Clean sinusoidal waveform with consistent amplitude and frequency that increases proportionally with wheel speed. At 25 MPH, expect approximately 250-300 Hz with 0.8-1.5V peak-to-peak. All four sensors should show nearly identical frequency at same vehicle speed with symmetrical positive and negative peaks.

Clean square wave transitioning sharply between 0V and 5V (battery voltage). At 25 MPH, frequency should be approximately 165 Hz (4000 pulses/mile). Rise and fall times should be less than 1ms with no ringing or oscillation. Signal should be present anytime vehicle is moving with transmission in gear.

At cold start (68°F), expect 2.0-2.5V. At normal operating temperature (195-210°F), voltage should be 0.3-0.7V with smooth, gradual decline during warm-up. No sudden jumps or dropouts. Voltage should remain stable at idle with minimal noise (less than 0.05V ripple).

At ambient temperature (68°F), expect 2.0-2.7V. Under hood heat soak can raise temperature to 140°F+ showing 0.8-1.2V. Signal should be smooth and stable with no fluctuations. During highway driving, intake temps drop and voltage rises toward ambient temperature values.

2022 Toyota Camry Waveform References

Airflow Sensors

Fuel System

Ignition System

Oxygen Sensors

Position Sensors

Speed Sensors

Temperature Sensors