Low Speed Fuel Pump Primary Circuit Malfunction The PCM monitors the low speed fuel pump (LFP) primary circuit output from the PCM.
The test fails if: When the LFP circuit is commanded on (grounded), excessive current draw is detected on the LFP circuit; or when the LFP circuit is commanded off, voltage is not detected on the LFP circuit (the PCM expects to detect VPWR voltage coming through the low speed fuel pump relay coil to the LFP circuit). Open or shorted low fuel pump (LFP) circuit Open VPWR to low speed fuel pump relay Damaged low speed fuel pump relay Damaged PCM An open circuit or short to ground can only be detected with the low speed fuel pump.
One example of this would be when an automatic vehicle in placed in gear. To prevent the added drag from the torque converter and transmission from reducing the idling speed, the PCM will command the idle control valve to allow more air to enter the engine, while at the same time, adjusting the injector pulse width to inject more fuel to suit the increased amount of air. Note that the idle air control valve is closed by the PCM when the throttle plate is opened to prevent excess air from entering the engine.
Difficulty Level (Expert)
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Repair Time (35 Min.)
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| Cost Prediction : $ 40-75 |
If your front doppler sensor circuit failure check engine light is illuminated, it's best to take it in for diagnostic testing, which can feel like a hassle. Because while the lights vary in appearance from vehicle to vehicle, all have the same basic meaning: There's a problem with the car's emissions system. The on-board diagnostics system C0540 and engine control unit are in charge of monitoring a bunch of different front doppler sensor circuit failure, and if they get a reading that's a little out of whack, up pops the check engine light.
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C0540 is a kind of Chassis Trouble Code
Diagnosing chassis noises can be one of the most frustrating problems technicians face. Fortunately, manufacturers have engineered noise, vibration and harshness (NVH) diagnostic techniques and equipment to find the source of the noise. |
You can view according C0540 DTC for your car model. We selected several models to see obd2 solutions click and view it.
| +C0540 Zender 30-7 | +C0540 Marcos Tso | +C0540 Alpine V6 | +C0540 Mitsubishi Pajero Iii | +C0540 Peugeot 404 |
Engine OBD 2 Codes website is a freeware resource center for engine trouble codes.
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