Service engine soon light is on. - 2004 Pontiac Grand Prix

It means time for a service.
Take it to your Nissan dealership for service.

Service engine soon ? Do you mean SERVICE VEHICLE SOON Indicator
The amber SERVICE VEHICLE SOON indicator is an alert to the driver whenever there are specific current codes stored in the BCM or in the event of a loss of Class 2 serial data.

If your vehicle has a check engine light ,it doesn't have service engine soon .One or the other .

Service Engine Soon

If the Service Engine Soon indicator light stays lit after you've started the engine, the On Board Diagnostics system (OBD) has detected a malfunction of the vehicle emissions control system. Contact your authorized dealer as soon as possible.
If indicator light is blinking, an engine misfire may be occurring, which could damage your catalytic converter. Drive in a moderate fashion (avoid heavy acceleration and deceleration), and have your vehicle serviced immediately.*
The Service Engine Soon indicator light illuminates when the ignition is first turned on (prior to engine start) in order to test the bulb, as well as indicate whether the vehicle is ready for Inspection/Maintenance (I/M) testing.
Normally, the Service Engine Soon light will stay on until the engine is cranked, then turn itself off if no malfunctions are present. However, if after 15 seconds this light blinks eight times, it means that the vehicle is not ready for I/M testing.Check this link out Gary.
https://owner.ford.com/how-tos/vehicle-features/dashboard-instrument-cluster/warning-lamps-and-indicators.html

There is a diagnostic procedure in the factory service repair manual for engine light lit ,no codes . Did you take it to ford dealer ? MIL - is referring to check engine , service engine soon etc...

• MIL always on when engine is running (no DTCs):
• MIL circuits

• For Focus, Mustang, Town Car, Continental, LS6/LS8, Escape, Windstar, F-150, Expedition and Navigator/Blackwood:
• Instrument Cluster, Section 413-01 of the Workshop Manual.
• All Others:
• GO to NB1

SERVICE ENGINE SOON indicator After the engine is started, the SERVICE ENGINE SOON indicator will prove out for a duration of three seconds. If the instrument cluster does not receive a message from the PCM within five seconds, the instrument cluster will illuminate the SERVICE ENGINE SOON indicator and log a diagnostic trouble code (DTC).

• An indicator is inoperative/always on - SERVICE ENGINE SOON

• Circuitry.
• Bulb.
• Instrument cluster.
• PCM.

• GO to Pinpoint Test P .

PINPOINT TEST P: AN INDICATOR IS INOPERATIVE/ALWAYS ON - SERVICE ENGINE SOON CONDITIONS DETAILS/RESULTS/ACTIONS P1 CARRY OUT THE INSTRUMENT CLUSTER SERVICE ENGINE SOON INDICATOR ACTIVE COMMAND Trigger the HEC active command MIL.

• Did the SERVICE ENGINE SOON indicator illuminate?

Yes REFER to Powertrain Control/Emissions Diagnosis (PC/ED) manual.

No INSTALL a new instrument cluster; REFER to Instrument Cluster . CLEAR the DTCs. REPEAT the self-test.

The service engine soon could be an indicator that you need to have minor maintenance done in the near future. I had a Grand Am that the service engine light would turn on when I was getting close to needing an oil change. You might check your owners manual for an exact reason as to why it turns on.

Service engine soon has nothing to do with service or maintenance . Emission's OBD 2 engine managment system . Light on ! DTC'S - diagnostic trouble codes stored . Your don't know THAT ! Your best bet , take it to the dealer .

should have two lights check engine and service engine soon.check engine means there is a malfunction.service soon is reprogrammable,when you change you oil. check you owners manual for reset.

I’m happy to help further over the phone at https://www.6ya.com/expert/kenneth_3efc1f8510674f04

I am assuming its not the service engine soon light it is probably the service vehicle soon light, There are 2 lights service vehicle soon upper left side, and service engine soon upper right side.

When all these come on at the same time it is the wheel bearing sensor. Usually the wheel bearing needs to be replaced which houses the sensor. A sure way to check is to press your sls button by your shifter and see if the light goes out, If it does not, u will need to have a wheel bearing put in.

one is service engine soon referring to the engine and trans. systems, and one is service vehicle soon, referring to body, abs, hvac, etc. systems two different lights for 2 different types of trouble codes