P043E - Evaporative Emission System (EVAP) Leak Detection Reference Orifice Low Flow
System
Powertrain (Engine & Gearbox)
Technical Description
The control module has detected a fault in the Evaporative Emission System (EVAP) Leak Detection Reference Orifice Low Flow (P043E).
Multimeter Test Points & Nominal Values
| Test Point / Component | Measurement | Nominal Target Range | Test Condition |
|---|---|---|---|
| Evaporative Emission System (EVAP) Leak Detection Reference Orifice Low Flow – Coil Resistance | Resistance (Ω) | 3 - 30 Ω (typical) | Connector disconnected at 20°C |
| Evaporative Emission System (EVAP) Leak Detection Reference Orifice Low Flow – Duty Cycle | PWM (%) | 5 - 95 % (modulates with target) | Engine running, actuator in control |
| Evaporative Emission System (EVAP) Leak Detection Reference Orifice Low Flow – Supply Voltage | Voltage (V) | 11.8 - 14.4 V | Ignition ON at connector |
Connector disconnected at 20°C
Engine running, actuator in control
Ignition ON at connector
Oscilloscope Waveform Analysis
2 ms/div, 20 V/divPossible Causes
Chafed or pinched wiring harness along the signal path to Evaporative Emission System (EVAP) Leak Detection Reference Orifice Low Flow
Internal mechanical wear or carbon deposits inside Evaporative Emission System (EVAP) Leak Detection Reference Orifice Low Flow
Defective internal output driver or reference circuit in the control module for Evaporative Emission System (EVAP) Leak Detection Reference Orifice Low Flow
Symptoms
4
Recommended Solution
Inspect and clean delivery passages for carbon buildup and measure differential flow pressure.
Verify loaded supply voltage and harness terminal pins at Evaporative Emission System (EVAP) Leak Detection Reference Orifice Low Flow.
Check circuit continuity and ground-side voltage drop (< 0.05 V) for Evaporative Emission System (EVAP) Leak Detection Reference Orifice Low Flow.
Check supply and the low-side driver at the ECM connector. Replace the actuator or repair the circuit based on the readings.
Mechanic's Tip
Use the scan-tool output test with the scope on the control side at the same time. If duty changes but the actuator does not move, the valve is stuck — not the electrical fault you were chasing.