What this code means

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

1. Check engine oil level and condition
2. Test oil pressure with mechanical gauge
3. Inspect oil pressure switch wiring
4. Test oil pressure switch for proper operation
5. 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.

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