SES Codes (beyond the paperclip codes)

[rkhassen]

My roomate just bought a code reader. We checked my engine many times over about a 300 mile driving period, giving the engine opportunity to reset and resend codes. The same ones keep appearing despite my unplugging the battery for 15 minutes to clear it. (97 Saturn DOHC)

These codes keep appearing, can anyone be so kind as to advise on what to do (yes I have to smog the car before the 30th in CA)

1. PO401 - I understand this is the EGR which I cleaned with carb cleaner. Or rather I tried to. There was so much gunk in there, I couldn't get it all out with carb cleaner and a tooth brush, let alone the spindle. Yes, the SES came back on after 50 miles or so. I ordered a used one for $55 today.

2. Oxygen Sensor Monitor Status : Not Complete
It says this every time (this is the 3rd test after resetting and resetting the computer by pulling the battery cables)

3. Catalyst Monitor Status : Not Complete
See the statement for the O2 Sensor

For 2, and 3 and O2 and Catalyst sensor, do I need to replace these monitors or can I ignore these?

Thanks!

[harsha]

Car running rich, possible ECTS problem. I saw somewhere you mentioned you replaced ECTS, but not the wiring?? 1st replace that wiring harness reset the codes and drive for sometime. If the codes come back, someone might help u.

[Uzzy]

OK, first, on the OBDII cars, you can't clear the codes by unplugging the batt. And you can't get any codes with a paper clip. The code reader is the only way to get codes, and that seems to be working. The only way to clear codes with with a code reader. The cheap ones will not clear codes, so you probably don't have them comming back all the time, it's the same codes. Do you have the SES on still? As for codes #2 and #3, check the O2 sensor wires, I guess.

[rkhassen]

Ok, that makes sense. We did clear the codes once with the code reader. But still get all of them including the mysterious 02 and Catalyst. I will check the wires. if not, I guess I am buying new sensors?

Thanks!

[Uzzy]

Originally Posted by rkhassen

Ok, that makes sense. We did clear the codes once with the code reader. But still get all of them including the mysterious 02 and Catalyst. I will check the wires. if not, I guess I am buying new sensors?

I'm not too good with my OBDII codes, but it seems that both O2 sensors (the exhaust manifold, and catalytic) are not being read. It's odd for both to not be read like this. It's not as if they are reading rich, or lean, just not reading, I think. Maybr the reason for the clogged EGR killed both O2 sensors? Not likely, but I've seen stranger things.

[DonP]

Ther are 30+ O2 sensor-related OBDII codes. Was there a code number for the oxygen sensor items you mention, or just that text on the scanner display?

[RangerRover]

Also - there may be nothing wrong with the wiring. The OBD2 tests require that a minimum of x miles be driven. When you reset an OBD2 computer, the various sensors related to emissions require a fair amount of drive time before they send the ready signal. Until then, the reader will simply display Not Ready or something to that effect. That may be what the Not Complete reading is showing. How far did you drive in between resetting the computer? A 97 Monte Carlo I worked on took about 75 miles of mixed highway and "spirited" driving to signal ready. The inspection shop guy told me that he saw one guy that took 120 miles at 35 mph before that car's reset.

Try driving the car on a nice long Sunday drive doing a mix of long stretches of highway and a sprinkle of city driving.

[Uzzy]

Originally Posted by RangerRover

Also - there may be nothing wrong with the wiring. The OBD2 tests require that a minimum of x miles be driven. When you reset an OBD2 computer, the various sensors related to emissions require a fair amount of drive time before they send the ready signal. Until then, the reader will simply display Not Ready or something to that effect. That may be what the Not Complete reading is showing. How far did you drive in between resetting the computer? A 97 Monte Carlo I worked on took about 75 miles of mixed highway and "spirited" driving to signal ready. The inspection shop guy told me that he saw one guy that took 120 miles at 35 mph before that car's reset.

Try driving the car on a nice long Sunday drive doing a mix of long stretches of highway and a sprinkle of city driving.

That's a good point.
Were those codes there before the reset? What were the P0xxx codes exactly?

[DonP]

Not complete: means that the car has not gone through the required driving cycle to complete all of the OBDII tests. The GM cycle - a lift from:
http://www.obdii.com/drivecycle.html?source=ar10

A complete driving cycle should perform diagnostics on all systems. A complete driving cycle can be done in under fifteen minutes.

To perform an OBDII Driving cycle do the following:

1. Cold Start. In order to be classified as a cold start the engine coolant temperature must be below 50°C (122°F) and within 6°C (11°F) of the ambient air temperature at startup. Do not leave the key on prior to the cold start or the heated oxygen sensor diagnostic may not run.
2. Idle. The engine must be run for two and a half minutes with the air conditioner on and rear defroster on. The more electrical load you can apply the better. This will test the O2 heater, Passive Air, Purge "No Flow", Misfire and if closed loop is achieved, Fuel Trim.
3. Accelerate. Turn off the air conditioner and all the other loads and apply half throttle until 88km/hr (55mph) is reached. During this time the Misfire, Fuel Trim, and Purge Flow diagnostics will be performed.
4. Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for 3 minutes. During this time the O2 response, air Intrusive, EGR, Purge, Misfire, and Fuel Trim diagnostics will be performed.
5. Decelerate. Let off the accelerator pedal. Do not shift, touch the brake or clutch. It is important to let the vehicle coast along gradually slowing down to 32km/hr (20 mph). During this time the EGR, Purge and Fuel Trim diagnostics will be performed.
6. Accelerate. Accelerate at 3/4 throttle until 88-96 km/hr (55-60mph). This will perform the same diagnostics as in step 3.
7. Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for five minutes. During this time, in addition to the diagnostics performed in step 4, the catalyst monitor diagnostics will be performed. If the catalyst is marginal or the battery has been disconnected, it may take 5 complete driving cycles to determine the state of the catalyst.
8. Decelerate. This will perform the same diagnostics as in step 5. Again, don't press the clutch or brakes or shift gears.

[rkhassen]

Heck, I drive 130 miles EVERY DAY. And since my car is frisky, (honest, officer, its the car, not me) we do tend to drive quite spirited. The only thing I didn't do was turn on the a/c and the defroster at the same time. But have done lights and radio and a/c. I would think I've gone a cycle. I will run the test again.

30 sensors???? Yikes.

[CND_SC1]

4. Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for 3 minutes. ...
5. Decelerate. Let off the accelerator pedal. Do not shift, touch the brake or clutch. It is important to let the vehicle coast along gradually slowing down to 32km/hr (20 mph).

I can't think of a single road where I could do both of these steps back to back. I'd have to go out of town, then sleep in the car 5 hours to cool it down for the cold start, and do this on a country highway before dawn to avoid getting rammed while decelerating...

[DonP]

Not 30 sensors but 30 different codes related to 02 sensors.