Pinpoint Test S: The Low Oil Pressure Warning Indicator Is Never/Always On
Instrumentation, Message Center and Warning Chimes
Pinpoint Tests
Pinpoint Test S: The Low Oil Pressure Warning Indicator Is Never/Always On
Refer to Wiring Diagram Set 60, Instrument Cluster for schematic and connector information. Diagrams By Number
Normal Operation
The engine oil pressure switch is a normally open switch that is hardwired to the Instrument Cluster (IC) through a single input circuit. When the engine oil pressure is within normal ranges, the engine oil pressure switch closes and grounds the signal to the IC, and the IC turns off the low oil pressure warning indicator. When engine oil pressure is low, the engine oil pressure switch opens, removing the ground signal to the IC, and the IC illuminates the low oil pressure warning indicator.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Base engine concern
- Engine oil pressure switch
- IC
PINPOINT TEST S: THE LOW OIL PRESSURE WARNING INDICATOR IS NEVER/ALWAYS ON
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
NOTICE: The electrical power to the air suspension system must be turned off prior to hoisting, jacking or towing an air suspension vehicle. Failure to do so can result in unexpected inflation or deflation of the air springs, which can result in shifting of the vehicle during these operations. Failure to follow these instructions may result in personal injury.
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S1 DETERMINE IF THE LOW OIL PRESSURE WARNING INDICATOR IS ALWAYS ON
- Start the engine.
- Observe the low oil pressure warning indicator.
- Is the low oil pressure warning indicator illuminated?
Yes
GO to S2.
No
GO to S5.
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S2 CHECK THE LOW OIL INDICATOR OPERATION
WARNING: Before servicing a vehicle equipped with a fire suppression system, depower the system. Failure to follow the instructions may result in serious personal injury Procedures.
- Ignition OFF.
- Disconnect: Engine Oil Pressure Switch C103 .
- NOTE: If the fused jumper wire fails, repair circuit 31 (WH/RD) for a short to voltage.
- Connect a fused jumper wire between the oil pressure switch C103-1, circuit 31 (WH/RD), harness side and ground.
- Ignition ON.
- Does the low oil pressure warning indicator illuminate?
Yes
REMOVE the jumper wire. GO to S3.
No
REMOVE the jumper wire. GO to S4.
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S3 CHECK THE LOW OIL PRESSURE INPUT CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: IC C2220 .
- Measure the resistance between the IC C2220-6, circuit 31 (WH/RD), and the oil pressure switch C103-1, circuit 31 (WH/RD), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to S7.
No
REPAIR the circuit. TEST the system for normal operation. If equipped with the fire suppression system, GO to S8.
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S4 CARRY OUT THE ENGINE OIL PRESSURE TEST
- Ignition OFF.
- Carry out the engine oil pressure test. Refer to Engine System - General Information Testing and Inspection.
- Is the engine oil pressure within specification?
Yes
INSTALL a new Engine Oil Pressure (EOP) switch. REFER to Engine - 4.6L (2V) Service and Repair. TEST the system for normal operation. If equipped with the fire suppression system, GO to S8.
No
REFER to Engine System - General Information Testing and Inspection to continue diagnosis of the oil pressure system. If equipped with the fire suppression system, GO to S8.
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S5 CARRY OUT THE IC PROVE OUT
WARNING: Before servicing a vehicle equipped with a fire suppression system, depower the system. Failure to follow the instructions may result in serious personal injury Procedures.
- Ignition OFF.
- Disconnect: Engine Oil Pressure Switch C103 .
- Ignition ON.
- Observe the low oil pressure indicator after the IC prove out.
- Does the low oil pressure warning indicator illuminate after the IC prove out?
Yes
INSTALL a new Engine Oil Pressure (EOP) switch. REFER to Engine - 4.6L (2V) Service and Repair. TEST the system for normal operation. If equipped with the fire suppression system, GO to S8.
No
GO to S6.
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S6 CHECK THE LOW OIL PRESSURE INPUT CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: IC C2220 .
- Measure the resistance between the IC C2220-6, circuit 31 (WH/RD), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to S7.
No
REPAIR the circuit. TEST the system for normal operation. If equipped with the fire suppression system, GO to S8.
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S7 CHECK FOR CORRECT IC OPERATION
- Disconnect the IC connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the IC connector and make sure it seats correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). If equipped with the fire suppression system, GO to S8.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. If equipped with the fire suppression system, GO to S8.
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S8 REPOWER THE FIRE SUPPRESSION SYSTEM
WARNING: If the vehicle is equipped with a fire suppression system, repower the system. For important safety warnings and procedures, Failure to follow these instructions may result in serious personal injuryProcedures.
- Verify that the fire suppression system is repowered. Procedures.
- Is the fire suppression system repowered?
Yes
The fire suppression system repowering is complete.
No
Procedures for the fire suppression system depowering and repowering procedure.
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