"Service Engine Soon" light...

[Max]

came on yesterday. Book says that it is emissions related. O2 sensor maybe? Tried disconnecting the baterry to re-set the ECU, but light remains on.

Any thoughts or suggestions on how to further troubleshoot? Will running a code diagnostic reader help?

[DesertTracker]

The most common cause of Service Engine Soon is a loose gas cap. The system senses loss of pressure in the evaporative emission system and sets the light.
On my 2000 2.0 Tracker, I get a service engine light occasionally and a P0400 code which is "Exhaust Gas Recirculation Flow Malfunction". Sometimes I reset it, sometimes I don't; when I don't it eventually goes away. I went as far once as pulling the EGR valve and checking it out. It was relatively clean and the resistance was correct. This makes me think that the monitoring system is not that precise.
I bought a Innova OBD2 code reader for $100 when a $30 rebate was offered so for $70 I can check the codes. It did help me troubleshoot a cracked coil lead that was misfiring. I would like to have a better scan tool that has more functions, like reading the timing and activating some of the controls and sensors, but they start at $400 and go up, way up!
Before I would change an oxygen sensor, I would check the gas cap, and take a look under the hood for anything obvious like a loose vacuum line and give the system a little time to reset itself. I believe after 10 drive cycles of not sensing the problem, the system resets itself and turns off the light.
If the light is flashing, this means something more serious has been detected and the need to identify the problem by actually reading the code is more urgent, but a steady light can be dealt with more slowly.

[Max]

Thanks for your input! I'll check connections and such as you suggested, as well as give it some time to MAYBE work out the bug on it's own.

At least the light is not flashing.

[tmcalavy]

Yeah, get a code reader if your the curious type. I got an OBDII reader on Ebay for about $50 and it reads the Zuke and the wife's PT Cruiser, also resets them, too. I have pulled O2 sensors cleaned with alcohol and haven't had that code return on my 99 GV, now I just run a can of Sea Foam through a half-tank of gas about two times a year...sensor safe and keeps the fuel system clean. If my 99 sits for several days in winter I always get a check engine light for about 5 driving cycles before it disappears...something I credit to winter gasoline.

[Max]

Well, while off on an errand just now, I stopped at a local Auto Parts store and had them run their code reader. "High voltage, O2 sensor, #2 bank". Sounds like that is the passenger side (right) sensor is bad, no?

I may try to clean it as mentioned TM. Need to change the oil any way, so I'll check that sensor while I'm at it. Clean it w/alcohol? How about Acetone or MEK? I've got that at work. Soak it, scrub it or just wipe down the outer portion?

[tmcalavy]

That's the code/message I was getting. I think it means the sensor is too cruddy to set the right voltage. Didn't have any acetone at the time, so I used some 95% alcohol that I had in the shop to clean outboard fuel tanks...just removed the two sensors I could get to and let them soak in it for a few hours...was amazed at the crud that it removed, then re-installed. My 99 now has over 100K so I guess I should consider replacing the sensors if the code returns...bout due, but it hasn't come back since I started using Sea Foam twice a year. Reckon acetone would do just as well...just let it soak a while.

[Max]

I'll try cleaning them tomorrow or replace at least that one. I've got over 200K on the engine and the sensors have never been changed. Bout' due! I also have another used 60K engine that I could take a sensor off of if a cleaning won't work. I'll let ya' know how it goes. Thanks again guys.

Who sells Sea Foam BTW?

[tmcalavy]

You can get Sea Foam at most auto parts stores, ie. Napa, Auto Zone, Advance, O'Reilly's. Don't know what's in it, but its aces for cleaning the innards...I use it for decarbing the old/neglected outboards that come my way for restoration.

[Max]

Yikes! Got under the old Zuki to check out the O2 sensor location after looking at the manual. 1st off the #2 bank IS the right side as I assumed earlier, BUT there are a total of FOUR sensors (two per side) one prior to, and one after the pre-cat just off the manifolds! The upper sensors are pretty tough to access, and those stupid electrical wiring CONNECTORS are even in a worse location to unplug! THAT will be the hard part of the operation.

I'm regrouping... 1st to get another code readout to see if they ID the UPPER or LOWER sensor to narrow down the repair, and maybe try a "wait and see" for another week to see if the light goes out on it's own (yeah right).

Looking at code readers on e-bay, and I'm off to hunt down some Sea Foam. Need to get the correct style sensor WRENCH as well if I'm pulling the upper sensors especially.

The two sensors are different too according to the attached (see Bosch comment)...
1999 SUZUKI GRAND VITARA 2.5L 2500cc V6 FI Oxygen Sensor

Also note the 100,000 mile mention to replace.

Need to check my gas mileage and see if it's down due to the sensor prob. The dang thing still RUNS great though.

More later...

Just had another thought IF I get a new "universal" style sensor that requires SPLICING into the existing 4-wire harness, then MAYBE I can just leave the plug-in portion connected! That in it's self will be a blessing!

Max

[DesertTracker]

I've read somewhere that the Zuks and Trackers are sensitive to aftermarket Oxygen sensors, but I don't have any first hand experience.
I order quite a few OEM parts from "Chevy Parts" below wholesale for my Tracker and have found that they are about 40% to 50% cheaper than my local dealer and even in line with the aftermarket parts stores. When I needed a coil, an aftermarket was $73, but I got an OEM for $78.
You may check online Suzuki parts dealers and get an OEM at a decent price.