Service Engine Soon question...

I recenly purchased a used 2001 SE Max 5 speed. The wife and I were out last Sunday (a week ago today) driving when the SES light came on steady. I checked the gas cap, which seemed to be on fine. Not sure what caused the light to come on. The only thing I recall is that we were on about a half tank of (93 Chevron) gas, and were going up and down some pretty steep hills. Doesn't seem like this could have anything to do with it, but... It did come just a few minutes after. Mid week, the tank got low, I added 93 Citgo, depleted that, and have since added another full tank of the 93 Chevron. I took it to AutoZone today, and they came back with the following code...

P0420: Catalyst System Efficiency Below Threshold (Bank 1)

The guy who ran the code didn't know what that meant, but asked someone else who said it had to do with octane/gasoline, and that I should try a different/higher level of octane... I told him I have been through two full tanks of 93, to which he didn't realy have any advice for. The light came on after we have put on over 500 miles on the car, and again has been on for about a week.

Could this be a pre-existing problem, such as the previous owner using cheap gas, and could the dealer have reset the ses light prior to purchase so it wouldn't show up until several hundred miles later, or could it be something completely different?

Any experience/feedback or additional info on this would be greatly appreciated.

Thanks, -Brian

 

According to the FSM:

Three way catalyst does not operate properly, three way catalyst does not have enough oxygen sotrage capacity.

Possible Causes:

Exhaust tube
Intake air leaks
Injectors
Injector leaks
Spark plug
Improper ignition timing

Email me if you want help diagnosing.

 

Bad O2 sensor, maybe?? I'd clear the code, and see if it comes back.

 

I dont think so, it would throw an O2 code if the O2 sensor went bad.

 

Wasnt there a TSB for bad ignition coils (that lead to bad plugs)????

 

There is a TSB on the coils, but a bad coil will generally throw a misfire code, even if it's intermittent.

When one of my coils went, it threw several codes, include the catalyst efficiency one. I figured it was related to the misfire, and it hasn't come back since the coil was replaced.

 

Thing is, the coil might not be totally bad, so it wouldnt misfire. It just wouldnt fire at peak efficiency. This would mos def cause the condition he had. I recommend he take the car in and have nissan look at it.

 

I had the same problem, light came on and went off several times last year. Finally, I took it to get it reset for the same code you described, waited and it came on again. Same code, took it to the dealer and they reprogrammed the ECU, it appears to have more power now and the light has not been on since.

 

You're right, it could very well be a coil on the way out. I'd make the same recommendation, but only if the guy knows and trusts his service writer. I've had too many bad experiences with the dealers I've seen to trust anything they say anymore.

 

I have this code currently. I took it to the dealer and they told me it was my cat converter. Luckily, it is under the emission warranty. Take it to the dealer and let them check it. They can possibly reprogram your ECM(there is an TSB on this) or get you a new cat converter like me. I am waiting on a new cat to come in and finally fix my SES light.

 

My SES indicator lit up on my vehicle approximately 6 months ago. The engine ran smoothly and I did not detect any difference in mileage or performance. Thinking that it was a loose gas cap or that it was due to heavy traffic conditions (prolong idling), I disconnected the battery for 2 minutes to turn SES light off.


It lit up again shortly thereafter and I reset the light again. However,I did notice that this time, the car was prone to stalling only when depressing clutch and letting up on the gas.


I knew that there was definitely a problem and brought it in to the dealer (SES light remained off). They put it on the OEM Diagnostic machine , however, no DTC codes were stored in the car's ECM control module. They performed a Idle Relearn Procedure and readjusted the idle a bit higher.


The light went on again 4 days after getting the car back from the dealer. This time they told me that a P0420 was stored on the ECU. Although this indicates a problem with the 3 Way Catalyst, they attributed the MIL indicator to a problem with the car's original ECM program. They updated the car with a new ECM program under Nissan TSB NTB00070 and sent me on my way. No other problems have been detected, although it has been only two weeks. Charged $85 for the initial visit but the TSB was covered under warrenty

http://www.nissan-techinfo.com/nissa...5.asp?mscssid=


I am aware that a TSB (NTB01059) is out for a Code P1320. This was released to correct faulty coils.

http://www.nissan-techinfo.com/nissa...9.asp?mscssid=

2K 5 Speed SE

 

My SES lite up this Sunday. I just got it scanned it also returned a P0240. Dealer told me to bring it in and they'll reprogram the ECU. What did that cost you if you don't mind my asking. My dealer said 80-
this sound right?

 

hmm.. Well i got my codes pulled for free since it was under the emmissions warranty. Tell them that it should be under the warranty. If they refuse, try to take it to another dealer that will do it for free.

 

Didnt cost me anything, the car is under warranty about 30k miles