Check engine warning light on what's wrong?

[tt2001]

'99 996 , 53500miles

I had my check engine light on today, unexpectedly.

It remains on while driving, I checked user manual, it not talk too much of it.

Where I should start?

Thanks,

[Loren]

Get the Pcode read by someone with a scan tool. Write down all the Pcodes and then post them here. Some parts stores will do this for free.

[tt2001]

Get the Pcode read by someone with a scan tool. Write down all the Pcodes and then post them here. Some parts stores will do this for free.

Loren,

Thanks again. you always so helpful.

Can I still drive the car? it's nothing different, so far.

[Periokid]

Yes, You can drive it. It is an emissions control issue. Check the gas cap first. Make sure it is tight.

[tt2001]

Periokid,

Thanks a lot !

I'll check it first.

[Loren]

Yes, You can drive it.  It is an emissions control issue.  Check the gas cap first.  Make sure it is tight.

You can drive the car if the CE light is on steady. If the CE light is flashing then no don't drive the car. That indicates a serious problem that could cause engine damage.

[drpaulmarsh]

Check out my post the other day it may help you... You can try to cut and paste this link into your browser or seach for it via my username or subject?

http://www.renntech.org/forums/index.php?showtopic=2292&hl=

Subject :

"Anyone got an ODB in San Diego?, Orange check engine light ODB equipment?..."

Username: drpaulmarsh

[tt2001]

Dear all,

Finally my CE light off after I tighten the coolant reservoir cap.

Any idea?

Anyway, I'm so happy for the problem solved.

Thanks a lot everyone .

[Noor]

I am not sure if the CEL has anything to do with the Coolant cap. It usually has something to do with the emission issues. I had mine come and go for some time. Would come on stay on for 2-3 days and then go away for 2-3 days.

It is mostly to do with a marginal O2 sensors. There are total of 6 sensors on a 996 and anyone going bad can turn this light on.

They replaced all six sensors in my car to fix the issue.

Keep an eye on the CEL light. If it comes back again have some decode the code and make sure it is not the O2 sensor.

Good Luck.

Noor.

[tt2001]

I am not sure if the CEL has anything to do with the Coolant cap. It usually has something to do with the emission issues. I had mine come and go for some time. Would come on stay on for 2-3 days and then go away for 2-3 days.

It is mostly to do with a marginal O2 sensors. There are total of 6 sensors on a 996 and anyone going bad can turn this light on.

They replaced all six sensors in my car to fix the issue.

Keep an eye on the CEL light. If it comes back again have some decode the code and make sure it is not the O2 sensor.

Good Luck.

Noor.

Noor,

You're exactly right.

The light on again today, now I think I need to look into the O2 issue.

Thank you.

Tommy

[Noor]

No Problem. Good luck with the issue.

[ruftec]

Hello,

What kind of instrument is used to read the codes? Can it be purchased?

Thanks

[tt2001]

Get the Pcode read by someone with a scan tool. Write down all the Pcodes and then post them here. Some parts stores will do this for free.

Loren,

After changed all four O2 sensors , the CEL still came back on after 10min.( I only disconnected the battery to reset it)

That's scanner reading:

P1115

P1119

P1117

P1121

I check the new parts number was different than the old one.

Ahead of catalytic 993.606118.01 (OLD) 996.606.161.178.01 (NEW, Black color)

After Catalytic 993.606.128.01(OLD) 996.606.161.168.01 (NEW, Blue color)

There's only one way (direction) the each connector can be plug in.

1. Did I use the wrong parts?

2. Do I have to reset it by OBD-2 Scanner instead disconnect battery?

Thank you,

Tommy

[Loren]

Looks like they gave you the wrong parts.

If your car is a MY99 (my parts list is dated 6-28-04 so these should be current):

Pre-cat sensor: 993 606 128 01 (the 996 number you have is for MY02 and newer)

After-cat sensor (next to muffler sleeve): 993 606 118 01 (the 996 number you have is for MY02 and newer).

What were your P-Codes before all this?

My experience has generally been that several oxygen sensor codes do NOT mean bad O2 sensors but that the O2 sensors are identifying another problem (like an air leak on the intake side).

[tt2001]

Loren,

After cleaned those old oxygen sensors by wire brush and put them back, the CEL not coming back so far.

Can you kindly email me the MY99 in case I have wrong parts again.

Thanks,

[tt2001]

Loren,

The CEL on again after one month -1000M ,

OBDII read as P1128 P1125 and P1130 I reset them , and not come

back for 20M drove.

Any idea?

Thanks

[Loren]

P1128 and P1130 point to an intake leak or low fuel pressure (for both engine banks. P1125 points to fuel pressure to high or EVAP canister leaking. Very odd to have too high and too low together. The obvious things are: look for an air leak (loose or cracked hose), change your fuel filter if you have over 30K on it, inspect the EVAP canister.

Any changes like BMC or K&N filter? or aftermarket intake?

[tt2001]

Where is EVAP canister located?

No after market filer nor intake system.

Fuel filter just changed within 30days.

Do you have the '99 996 intake diagram for my tracing?

Thank you much.

Tommy

[Flakarter]

My P1130 code problem, on my 99' C2, was a mass air flow (MAF) sensor. See this thread:

MAF

It also threw out other codes as well, but once the MAF was replaced 6-8 months ago, no more CEL! :clapping:

Very easy to replace. Literally less than 2 minutes, at most.

Dean

[tt2001]

Thank you Dean. I will try to order a MAF today.

Tommy