Test J: The Low Oil Pressure Warning Indicator Is Never/Always On

PINPOINT TEST J: THE LOW OIL PRESSURE WARNING INDICATOR IS NEVER/ALWAYS ON

Normal Operation
The smart junction box (SJB) is hardwired to the engine oil pressure switch. The engine oil pressure switch unit consists of a diaphragm and contact points, which are normally open. When there is low (under 41 kPa [6 psi]) or no oil pressure, the engine oil pressure switch remains open, removing the ground to the SJB. When sufficient oil pressure exists, the engine oil pressure switch closes providing a ground signal to the SJB. The SJB monitors the oil pressure ground signal and sends a message to the instrument cluster (IC) to operate the oil pressure gauge according to the engine oil pressure.

The engine oil pressure switch is hardwired to the SJB through circuit 208 (GY). When the oil pressure is within normal ranges, the engine oil pressure switch closes, grounding the signal to the SJB. The SJB then sends a message to the instrument cluster (IC) through the communication network to command the low oil pressure warning indicator off. When engine oil pressure is low, the engine oil pressure switch opens, removing the ground to the SJB. The SJB sends a low oil pressure message to the instrument cluster (IC) through the communication network to command the low oil pressure warning indicator on.

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Engine oil pressure switch
- SJB
- Instrument cluster (IC)

J1-J4:

J4-J7:

J8: