Oil Pressure Lamp Control Circuit Malfunction (Chevrolet)
What does P1663 mean?
The P1663 code means the vehicle's onboard diagnostic system has detected: Oil Pressure Lamp Control Circuit Malfunction (Chevrolet). This is a moderate severity code.
Common Symptoms
- Oil pressure warning light stays on
- Oil pressure warning light does not illuminate
- Check Engine Light on
- Inaccurate oil pressure gauge reading
- No low oil pressure warning
Probable Causes (Ranked by Likelihood)
- Faulty oil pressure sensor or switch Very High
- Open or shorted wiring to oil pressure sensor High
- Instrument cluster circuit malfunction Moderate
- PCM oil pressure lamp driver failure Low
Step-by-Step Diagnostic Procedure
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Install a mechanical oil pressure gauge to verify actual oil pressure (should be 25+ psi at idle).
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If actual pressure is normal, test the oil pressure sensor with a multimeter for proper resistance changes.
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Inspect the wiring between the oil pressure sensor and instrument cluster or PCM.
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Check the instrument cluster for proper bulb function during key-on bulb check.
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If the sensor and wiring are good but the lamp malfunctions, test the PCM oil pressure lamp driver circuit.
Frequently Asked Questions
Should I be worried about engine damage?
First verify actual oil pressure with a mechanical gauge. If real pressure is normal, the issue is electrical. If actual pressure is low, stop driving immediately to prevent engine damage.
Can I replace the oil pressure sensor myself?
Yes, on most GM trucks and SUVs the sensor is accessible and replacement is straightforward with a deep socket or sensor socket.
Where is the oil pressure sensor located?
On most GM V8 engines, it is near the rear of the engine block above the oil filter. On 4-cylinder models, it is typically near the oil filter housing.