Oil Pressure Gauge: Testing and Inspection

Fig. 26, Checking Oil Pressure Gauge (Miata):

Continue checks for at least two minutes each to correctly judge condition. Allowable indication error is twice the width of the needle.
1. Disconnect electrical connector from oil pressure sensor and connect red lead of checker 49 0839 285 to yellow/red terminal wire and black lead to body ground.
2. Turn ignition switch to On position and proceed as follows:
a. Set checker to 16 ohms. Gauge should indicate 90 psi.
b. Set checker to 41 ohms. Gauge should indicate 30 psi.
c. Set checker to 52 ohms. Gauge should indicate 0 psi.

3. If gauge indicates correctly, replace oil pressure sensor.
4. If gauge does not indicate correctly, proceed to next step.
5. Remove instrument cluster.
6. Apply battery voltage to terminal 2k and ground terminal 2j, Fig. 26, then connect red lead of checker to terminal 2b and black lead to ground.
7. Repeat steps 2, 3 and 4.
8. If gauge indicates correctly, repair wiring harness.
9. If gauge does not indicate correctly, replace oil pressure gauge.