The Nissan forklift error code E43 indicates a problem with the air/fuel mixture ratio. Specifically, it means the ratio doesn’t cross the stoichiometric point for an extended period during closed-loop operation. This essentially means the engine is running too lean or too rich, and the oxygen sensor is not detecting the necessary fluctuations in the exhaust gases. This article will guide you through diagnosing and resolving this issue.
Understanding Nissan Forklift Code E43
After the engine warms up and enters closed-loop operation, the oxygen sensor should constantly switch between detecting a lean and rich mixture. With code E43, this switching doesn’t occur. The sensor voltage might get stuck low, middle, or high, indicating a consistently lean or rich condition. This prevents the engine from achieving optimal combustion efficiency.
Diagnosing the Problem
Begin by clearing the DTC (Diagnostic Trouble Code) and any diagnostic codes in the active test. Then, perform a fast TAS (Throttle Actuator System) or relearn the air idle volume with the engine warmed up and idling. Keep in mind that the relearn process won’t complete if the underlying issue persists.
After the relearn, verify the following parameters:
- Engine Timing: Should read between 0 and -1 degrees.
- A/F Alpha LPG: Should be within the specified range of 75 to 100.
- Engine Coolant Temperature: Should be between 83°C and 94°C.
- Battery Voltage: Should be between 12.5V and 14.9V at idle.
- Fuel Pressure: Should be between 25 and 31 kPa at idle with a warm engine.
Next, using a laptop diagnostic program, check the LPG injection pulse on the output monitor. It should measure between 5800 and 6900 m/sec at idle.
Common Causes of Nissan Forklift Code E43
Several issues can trigger the E43 code:
- Air Leaks: Look for leaks in the air horn between the mass air flow sensor and the injection holder. Loose bolts are a common culprit.
- Faulty Air Temperature Sensor: Incorrect readings from the air temperature sensor can disrupt the air/fuel mixture calculation. Check for discrepancies between the sensor reading and the actual air temperature, or for an open circuit in the sensor wiring.
- Damaged Cup Seal: A leaking or damaged cup seal between the injection holder and the throttle body can introduce unmetered air into the engine.
- Clogged Fuel Filter: A restricted fuel filter in the injection holder limits fuel flow, leading to a lean mixture.
Conclusion
Troubleshooting the Nissan forklift code E43 requires a systematic approach. By following the diagnostic steps outlined above and carefully inspecting the potential problem areas, you can effectively identify and resolve the underlying issue, restoring your forklift to optimal performance. If the problem persists after these checks, consult a qualified Nissan forklift technician for further assistance.
