Engine Oil Pressure Switch Circuit
2004-2007 Buick Rainier 4.2L I6
Description
The PCM detected a fault in the engine oil pressure switch circuit. The switch is normally closed at low oil pressure and opens when oil pressure exceeds 1-4.5 PSI. The PCM supplies 12V to the circuit and monitors for an open condition.
Symptoms
- Low oil pressure warning light (intermittent or false)
- Check Engine Light may not illuminate (non-emissions code)
- Oil gauge inaccuracy
Common Causes
- Faulty oil pressure switch
- Low engine oil level
- Oil pressure sensor wiring issue
- Corroded connector near oil filter
- Actual low oil pressure (worn engine)
Diagnostic Steps
- Check engine oil level and condition
- Test oil pressure with mechanical gauge
- Inspect oil pressure switch wiring
- Test oil pressure switch for proper operation
- Check connector near oil filter for corrosion
Repair Notes
Replace oil pressure switch (located near oil filter on most GM engines). If actual oil pressure is low, investigate engine mechanical condition.
Related Codes
Other Powertrain Codes
- P0001Fuel Volume Regulator Control Circuit/Open
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0003Fuel Volume Regulator Control Circuit Low
- P0004Fuel Volume Regulator Control Circuit High
- P0010Intake Camshaft Position Actuator Circuit/Open Bank 1
- P0011Intake Camshaft Position Timing Over-Advanced Bank 1
- P0012Intake Camshaft Position Timing Over-Retarded Bank 1
- P0013Exhaust Camshaft Position Actuator Circuit/Open Bank 1
- P0014Exhaust Camshaft Position Timing Over-Advanced Bank 1
- P0015Exhaust Camshaft Position Timing Over-Retarded Bank 1
P1189 on Other Vehicles
Common Questions
What does code P1189 mean on a 2004-2007 Buick Rainier?
P1189 stands for "Engine Oil Pressure Switch Circuit". The PCM detected a fault in the engine oil pressure switch circuit. The switch is normally closed at low oil pressure and opens when oil pressure exceeds 1-4.5 PSI. The PCM supplies 12V to the circuit and monitors for an open condition.
What are the symptoms of P1189 on a Buick Rainier?
Common symptoms of P1189 include: Low oil pressure warning light (intermittent or false), Check Engine Light may not illuminate (non-emissions code), Oil gauge inaccuracy.
What causes P1189 on a 2004-2007 Buick Rainier?
Common causes of P1189 include: Faulty oil pressure switch, Low engine oil level, Oil pressure sensor wiring issue, Corroded connector near oil filter, Actual low oil pressure (worn engine).