Pinpoint Test G: Incorrect Oil Pressure Gauge Indication
Instrumentation, Message Center and Warning Chimes
Pinpoint Tests
Pinpoint Test G: Incorrect Oil Pressure Gauge Indication
Refer to Wiring Diagram Set 60, Instrument Cluster for schematic and connector information. Diagrams By Number
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 IC through the communication network to command the oil pressure gauge into the normal range. 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 IC through the communication network to command the oil pressure gauge to the low oil pressure range.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Engine oil pressure switch
- SJB
- IC
PINPOINT TEST G: INCORRECT OIL PRESSURE GAUGE INDICATION
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
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G1 CARRY OUT THE IC TACHOMETER ACTIVE COMMAND USING THE SCAN TOOL
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IC DataLogger.
- Select the IC oil pressure gauge (OIL_POS) active command on and off while monitoring the oil pressure gauge.
- Does the oil pressure gauge start at the low range and increase to the normal range when commanded on?
Yes
If the oil pressure gauge always indicates normal, GO to G2.
If the oil pressure gauge always indicates low, GO to G4.
No
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.
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G2 CHECK THE ENGINE OIL PRESSURE SWITCH
- Ignition OFF.
- Disconnect: Engine Oil Pressure Switch C103.
- Ignition ON.
- With the engine oil pressure switch disconnected, monitor the oil pressure gauge.
- Does the oil pressure gauge indicate low?
Yes
INSTALL a new engine oil pressure switch. TEST the system for normal operation.
No
GO to G3.
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G3 CHECK CIRCUIT 208 (GY) FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: SJB C2280c.
- Measure the resistance between the SJB C2280c-42, circuit 208 (GY), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to G7.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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G4 CHECK THE ENGINE OIL PRESSURE SWITCH
- Ignition OFF.
- Disconnect: Engine Oil Pressure Switch C103.
- Connect a fused jumper wire between the engine oil pressure switch C103-1, circuit 208 (GY), harness side and ground.
- Ignition ON.
- Does the oil pressure gauge indicate normal?
Yes
REMOVE the jumper wire. GO to G6.
No
REMOVE the jumper wire. GO to G5.
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G5 CHECK CIRCUIT 208 (GY) FOR AN OPEN
- Ignition OFF.
- Disconnect: SJB C2280c.
- Measure the resistance between the SJB C2280c-42, circuit 208 (GY), harness side and the engine oil pressure switch C103-1, circuit 208 (GY), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to G7.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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G6 CHECK THE OIL PRESSURE
- Carry out the engine oil pressure test. Oil Pressure Test
- Is the oil pressure within specification?
Yes
INSTALL a new engine oil pressure switch. TEST the system for normal operation.
No
REFER to Engine. Testing and Inspection
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G7 CHECK FOR CORRECT SJB OPERATION
- Disconnect all the SJB connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the SJB connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new SJB. TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.
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