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.
Circuit High Input codes like C1964 are mostly caused by defective alternators that develop excessive voltages, although there may be other causes as well, such as short circuits that 'leak' current into a particular system from other, unrelated systems that work on higher voltages. Note that in the case of short circuits that leak power into a control circuit, there is likely to be other, seemingly unrelated trouble codes present along with the code(s) being investigated. Diagnosing a 'high input' code will always involve a thorough testing of the charging system as a first step, followed by measures to isolate the system from all other possible sources of power during resistance, continuity, and reference voltage tests.
When you turn on the ignition, the Service Engine Soon or Check Engine C1964 light should flash briefly, indicating that the OBD system is ready to scan your vehicle for any malfunctions. After this brief flash, the light should stay off while you drive as long as no problems are detected. If exhaust pressure sensor malfunction so, you'll be glad to know that your vehicle is equipped with an early warning system that could save you time, money, and fuel in addition to helping protect the exhaust pressure sensor malfunction.
Difficulty Level (Easy)
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Repair Time (45 Min.)
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Cost Prediction : $ 75-90 |
C1964 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 C1964 DTC for your car model. We selected several models to see obd2 solutions click and view it.