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P0521-OIL PRESSURE SWITCH RATIONALITY
For a complete wiring diagramRefer to Section 8W.
Page 690 of 5267
When Monitored:
Whilethekeyison.
Set Condition:
Oil pressure is detected with engine RPM = 0 for 30 seconds.
Possible Causes
OIL PRESSURE SWITCH
(G6) SIGNAL CIRCUIT OPEN
INTERMITTENT CONDITION
ECM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.OIL PRESSURE SWITCH
Turn the ignition off.
Disconnect the Oil pressure switch harness connector.
Check connectors - Clean/repair as necessary.
Measure the resistance between theoil pressure switch terminal and
ground.
Is the resistance less than 10 ohms?
Ye s>>
Go To 2
No>>
Replace the oil pressure switch.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
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2.(G6) SIGNAL CIRCUIT OPEN
Disconnect the ECM harness connectors.
Check connectors - Clean/repair as necessary.
Measure the resistance of the oil pressure switch (G6) signal circuit
between the oil pressure switch harness connector and the ECM har-
ness connector.
Is the resistance less than 10 ohms?
Ye s>>
Go To 3
No>>
Repair the open Oil pressure (G6) signal circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
3.ECM
Reconnect the ECM harness connectors.
Turn the ignition on.
Measure the voltage between the oil pressure (G6) signal circuit at the
oil pressure switch harness connector and ground.
Is the voltage between 4.5 and 5.5 volts?
Ye s>>
Refer to the INTERMITTENT CONDITION Symptom (Diag-
nostic Procedure). (Refer to 9 - ENGINE - DIAGNOSIS
AND TESTING)
No>>
Replace the ECM.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
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P0524-OIL PRESSURE TOO LOW
For a complete wiring diagramRefer to Section 8W.
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When Monitored:
While the engine is running.
Set Condition:
The oil pressure detected by the ECM is less than a calibrated value.
Possible Causes
LOW OIL LEVEL
(G6) SIGNAL CIRCUIT SHORT TO GROUND
OIL PRESSURE SWITCH
INTERNAL ENGINE DAMAGE
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.LOW OIL LEVEL
Check the engine oil level.
Is the engine oil in the safe operating range?
Ye s>>
Go To 2
No>>
Repair any condition that may cause the oil level to be above or below the safe operating range.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
2.SIGNAL CIRCUIT SHORT TO GROUND
With the scan tool, erase DTCs.
Turn the ignition off.
Disconnect the oil pressure switch harness connector.
Turntheignitiononfor1minute.
Did DTC P0521 set?
Ye s>>
Go To 3
No>>
Repair the (G6) signal circuit shorted to ground.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
3.OIL PRESSURE SWITCH
Measure the engine oil pressure with a mechanical gauge.
Is the oil pressure within the acceptable operating range?
Ye s>>
Replace the oil pressure switch.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Repair internal engine damage.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
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P0532-A/C SENDING UNIT VOLTS TOO LOW
For a complete wiring diagramRefer to Section 8W.
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When Monitored:
With the ignition on and battery voltage greater than 10.4 volts.
Set Condition:
The circuit voltage to the ECM falls below a calibrated threshold for a certain period of time.
Possible Causes
OTHER DTC’S
A/C PRESSURE SENSOR
(C918) SIGNAL CIRCUIT SHORTED TO (K55) RETURN CIRCUIT
(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO (K55) RETURN CIRCUIT
(C918) SIGNAL CIRCUIT OPEN FROM ECM HARNESS CONNECTOR TO A/C HARNESS CONNECTOR
(F855) 5-VOLT SUPPLY CIRCUIT OPEN FROM ECM HARNESS TO A/C HARNESS CONNECTORS
(C918) SIGNAL CIRCUIT SHORTED TO GROUND
(F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
ECM
INTERMITTENT CONDITION
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.OTHER DTC’S
Turn the ignition on.
With the scan tool, read DTCs.
Are other DTC’s present?
Ye s>>
Repair other DTC’s first.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 2
2.HARNESS OPEN
Disconnect the A/C pressure sending unit harness connector.
Check connectors - Clean/repair as necessary.
Measure the voltage between the (F855) 5-volt supply and (K916)
return circuits of the sensor harness connector.
Is the voltage between 4.5 and 5.5 volts?
Ye s>>
Go To 3
No>>
Go To 4
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3.A/C PRESSURE SENSOR
While monitoring scan tool, use a jumper wire to connect the (F855)
5-volt supply circuit to the (C918) signal circuit at the sensor harness
connector.
Did P0533 set?
Ye s>>
Replace the A/C pressure sensor.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
No>>
Go To 4
4.(C918) SIGNAL CIRCUIT SHORTED TO THE (K916) RETURN CIRCUIT
Turn the ignition off.
Disconnect the ECM harness connectors.
Measure the resistance between the (C918) signal circuit and (K916)
return circuit in the sensor harness connector.
Is the resistance greater than 100k Ohms?
Ye s>>
Go To 5
No>>
Repair the (C918) signal circuit shorted to the (K916) return
circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)