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2003 silverado oil pressure gauge maxed out
Fault detection:
When the ignition switch is turned on or off, the oil pressure gauge always indicates the full scale. When the engine is not started, the oil has no pressure, and the oil gauge should return to zero when the ignition switch is turned on. After analysis, this fault should be detected from three aspects: (1) oil pressure sensor; (2) Line; (3) Instrumentation.
First, find the oil pressure sensor near the oil filter. This sensor is unique. It is a dual function four wire plug sensor. Remove the plug to measure the resistance of A - B pins of the sensor, and C - D pins are ∞, indicating that the sensor is good. Turn on the ignition switch, and then measure the harness side plug. Pin A is not on fire and pin B is grounded, indicating that there is a problem with the sensor signal terminal circuit, instrument or power fuse. Remove the instrument assembly and measure whether there is fire at the power supply end. Manually set the needle to the initial position, and connect the positive and negative terminals of the three terminals of the oil meter to the output end of the stabilized voltage power supply. At this time, the needle quickly points to the maximum. When the signal terminal (connected to the sensor) is shorted to the negative terminal, the needle quickly returns to the zero position. When a variable resistor is sent by a resistor, the meter needle can stay at any position, thus proving that the instrument is in good condition. It seems that the problem must be in the circuit. After checking, the signal circuit is blocked. Because it is difficult to find the harness, the 2003 silverado engine oil gauge indicates the maximum fault after the wire is reconnected.
Summary of maximum faults indicated by 2003 silverado oil gauge. The failure of oil pressure gauge with no indication or excessive indication is generally simple in detection and analysis, and will not be described here. There are two points worth our attention and discussion through this example.
(1) Structure principle and analysis of instruments: At present, there are basically two types of indicating instruments (pressure gauge, temperature gauge, liquid level gauge, etc.) in many models. One is the old bimetallic sheet lever type instrument. The coil current flowing through the bimetallic sheet changes with the change of sensor resistance.
(2) One of the characteristics of Chevrolet series is that the oil pressure sensor is a dual function four wire device (most models are single wire system). Wire A and B are the oil pressure sensor leads, gray black is the signal lines, and wire C and D are the normally open contact switch leads. It is in parallel with the normally open contact of the fuel pump relay for protection and replacement of the relay.
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