P1189

Refer to Engine Controls Schematic IAC PCM ENG OIL LVL Engine Oil Pressure.

Diagnostic Chart:

CIRCUIT DESCRIPTION
The low oil pressure sensor is normally closed. When the oil pressure increases above 1 to 4.5 psi the switch contacts open. The Powertrain Control Module (PCM) supplies 12.0 volts to the oil pressure input circuit. With low oil pressure the 12 volts is pulled low to ground. This diagnostic tests for an open condition of the oil pressure switch circuit. If the engine has been OFF long enough for engine temperature to drop by 10°C (50°F), then a shorted (low oil pressure) condition of the circuit should be observed prior to engine running. If the engine has not been cranked and oil pressure has been detected, DTC P1189 will set.

CONDITIONS FOR RUNNING THE DTC
^ DTCPO117,P0118,P1111,and P1114 not set
^ Ignition ON
^ Engine OFF
^ Engine temperature 10°C (50°C) less than last key OFF temperature

CONDITIONS FOR SETTING THE DTC
Circuit open for 10 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM will not illuminate the Malfunction Indicator Lamp (MIL).
^ The PCM will store conditions which were present when the DTC set as Failure Records data only. This information will not be stored as Freeze Frame data.

CONDITIONS FOR CLEARING THE MIL/DTC
^ A History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using a scan tool.

DIAGNOSTIC AIDS
Test the oil pressure sensor input and ground circuits for an intermittent open or poor oil pressure sensor terminal contact. With the engine OFF the oil pressure display on the scan tool should indicate LOW. An open switch or a circuit would indicate LOW with the engine OFF.

IMPORTANT: Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.

^ Poor terminal connection-Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Use a corresponding mating terminal to test for proper tension.
^ Damaged harness-Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault.
^ PCM and engine grounds for clean and secure connections

If the DTC is determined to be intermittent, reviewing the Failure Records can be useful in determining when the DTC was last set.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table:
2. Tests to see if the fault is present. Low should be displayed with the engine not running.
3. Tests to see if the oil pressure switch or wiring is at fault.
4. Tests to see if the oil pressure switch input circuit or the PCM is at fault.