check engine light on in 97 wrangler YJ with error code reading 72
 

I have a check engine light on, and the code is reading a 12 and a 72.
I know what the 12 means, but could not find any explanation for a
reading of 72. Anyone know what this means?

Re: check engine light on in 97 wrangler YJ with error code reading 72
 

bspear78 wrote:
> I have a check engine light on, and the code is reading a 12 and a 72.
> I know what the 12 means, but could not find any explanation for a
> reading of 72. Anyone know what this means?

72 Catalyst efficiency below required level. (Same as code 64)

This means one of two things.
1) your catalytic converter is plugging/cracking/failing
2) the O2 sensor behind the cat is failing

This code is set when the second O2 sensor does not detect the
cat convertor working after warmup.

This is not a critical code, but if the cat is failing (plugging)
then your acceleration and fuel economy will suffer.

--
DougW

Re: check engine light on in 97 wrangler YJ with error code reading 72
 

bspear78 wrote:
> I have a check engine light on, and the code is reading a 12 and a 72.
> I know what the 12 means, but could not find any explanation for a
> reading of 72. Anyone know what this means?

72 Catalyst efficiency below required level. (Same as code 64)

This means one of two things.
1) your catalytic converter is plugging/cracking/failing
2) the O2 sensor behind the cat is failing

This code is set when the second O2 sensor does not detect the
cat convertor working after warmup.

This is not a critical code, but if the cat is failing (plugging)
then your acceleration and fuel economy will suffer.

--
DougW

Re: check engine light on in 97 wrangler YJ with error code reading 72
 

bspear78 wrote:
> I have a check engine light on, and the code is reading a 12 and a 72.
> I know what the 12 means, but could not find any explanation for a
> reading of 72. Anyone know what this means?

72 Catalyst efficiency below required level. (Same as code 64)

This means one of two things.
1) your catalytic converter is plugging/cracking/failing
2) the O2 sensor behind the cat is failing

This code is set when the second O2 sensor does not detect the
cat convertor working after warmup.

This is not a critical code, but if the cat is failing (plugging)
then your acceleration and fuel economy will suffer.

--
DougW

Re: check engine light on in 97 wrangler YJ with error code reading 72
 

bspear78 wrote:
> I have a check engine light on, and the code is reading a 12 and a 72.
> I know what the 12 means, but could not find any explanation for a
> reading of 72. Anyone know what this means?

72 Catalyst efficiency below required level. (Same as code 64)

This means one of two things.
1) your catalytic converter is plugging/cracking/failing
2) the O2 sensor behind the cat is failing

This code is set when the second O2 sensor does not detect the
cat convertor working after warmup.

This is not a critical code, but if the cat is failing (plugging)
then your acceleration and fuel economy will suffer.

--
DougW

Re: check engine light on in 97 wrangler YJ with error code reading 72
 

On Sun, 14 Jan 2007 14:41:18 -0600, "DougW"
<post.replies@invalid.address> wrote:

>bspear78 wrote:
>> I have a check engine light on, and the code is reading a 12 and a 72.
>> I know what the 12 means, but could not find any explanation for a
>> reading of 72. Anyone know what this means?
>
>72 Catalyst efficiency below required level. (Same as code 64)
>
>This means one of two things.
>1) your catalytic converter is plugging/cracking/failing
>2) the O2 sensor behind the cat is failing

If the downstream O2 was failing you'd get a downstream O2 fault, not
a cat efficiency fault.

>
>This code is set when the second O2 sensor does not detect the
>cat convertor working after warmup.
>
>This is not a critical code, but if the cat is failing (plugging)
>then your acceleration and fuel economy will suffer.

Re: check engine light on in 97 wrangler YJ with error code reading 72
 

On Sun, 14 Jan 2007 14:41:18 -0600, "DougW"
<post.replies@invalid.address> wrote:

>bspear78 wrote:
>> I have a check engine light on, and the code is reading a 12 and a 72.
>> I know what the 12 means, but could not find any explanation for a
>> reading of 72. Anyone know what this means?
>
>72 Catalyst efficiency below required level. (Same as code 64)
>
>This means one of two things.
>1) your catalytic converter is plugging/cracking/failing
>2) the O2 sensor behind the cat is failing

If the downstream O2 was failing you'd get a downstream O2 fault, not
a cat efficiency fault.

>
>This code is set when the second O2 sensor does not detect the
>cat convertor working after warmup.
>
>This is not a critical code, but if the cat is failing (plugging)
>then your acceleration and fuel economy will suffer.

Re: check engine light on in 97 wrangler YJ with error code reading 72
 

On Sun, 14 Jan 2007 14:41:18 -0600, "DougW"
<post.replies@invalid.address> wrote:

>bspear78 wrote:
>> I have a check engine light on, and the code is reading a 12 and a 72.
>> I know what the 12 means, but could not find any explanation for a
>> reading of 72. Anyone know what this means?
>
>72 Catalyst efficiency below required level. (Same as code 64)
>
>This means one of two things.
>1) your catalytic converter is plugging/cracking/failing
>2) the O2 sensor behind the cat is failing

If the downstream O2 was failing you'd get a downstream O2 fault, not
a cat efficiency fault.

>
>This code is set when the second O2 sensor does not detect the
>cat convertor working after warmup.
>
>This is not a critical code, but if the cat is failing (plugging)
>then your acceleration and fuel economy will suffer.

Re: check engine light on in 97 wrangler YJ with error code reading 72
 

On Sun, 14 Jan 2007 14:41:18 -0600, "DougW"
<post.replies@invalid.address> wrote:

>bspear78 wrote:
>> I have a check engine light on, and the code is reading a 12 and a 72.
>> I know what the 12 means, but could not find any explanation for a
>> reading of 72. Anyone know what this means?
>
>72 Catalyst efficiency below required level. (Same as code 64)
>
>This means one of two things.
>1) your catalytic converter is plugging/cracking/failing
>2) the O2 sensor behind the cat is failing

If the downstream O2 was failing you'd get a downstream O2 fault, not
a cat efficiency fault.

>
>This code is set when the second O2 sensor does not detect the
>cat convertor working after warmup.
>
>This is not a critical code, but if the cat is failing (plugging)
>then your acceleration and fuel economy will suffer.

Re: check engine light on in 97 wrangler YJ with error code reading 72
 

"bllsht" <nospam@dot.net> wrote in message
news:567mq2lcmmf2td23fj2mo0bsfndgffg805@4ax.com...
> On Sun, 14 Jan 2007 14:41:18 -0600, "DougW"
> <post.replies@invalid.address> wrote:
>
>>bspear78 wrote:
>>> I have a check engine light on, and the code is reading a 12 and a 72.
>>> I know what the 12 means, but could not find any explanation for a
>>> reading of 72. Anyone know what this means?
>>
>>72 Catalyst efficiency below required level. (Same as code 64)
>>
>>This means one of two things.
>>1) your catalytic converter is plugging/cracking/failing
>>2) the O2 sensor behind the cat is failing
>
> If the downstream O2 was failing you'd get a downstream O2 fault, not
> a cat efficiency fault.
>

I'm not sure that is true in an OBD I car. The CAT is not a likely source of
problems, and my money is on the after-CAT sensor going bad.

I am pretty sure that the downstream sensor can give an error that says the
CAT is failing. This can happen because the system doesn't know that the
sensor is bad, it only knows that the input from the sensor is not correct.
The sensor can fail in a mode that makes the system say that the CAT is not
working when the reality is that the sensor itself has taken a bye.

Having said all of that, the OP says he has a 97 YJ. In the 97, it was
called a TJ, and in 97, the codes are OBD II.