Help with CEL codes

[jkeenan94]

Hi all,

I have been experiencing an intermittent check engine light on my '94 Ranger 4.0 V6, and I did the "jump wire" test with the EEC and pulled the codes 175, 176, 181, and 189. These all seem to deal with mixture and the O2 sensors, is it most likely that my O2 sensors need replacing or could it be a more serious issue like a problem with the manifold? I do not believe the O2 sensors have ever been replaced, but I'm the third owner so its possible one of the other owners had it done.

Thanks!

 

[MrShorty]

3 of the 4 are for the left/front O2 sensor. I know it is not helpful, but, yes, it could be that your O2 sensor needs replacing or something else.

"By the book" one would explore further before replacing anything. It seems that many will replace the O2 sensor, clear the code, and see if the code goes away (especially if the O2 sensor is probably due to be replaced anyway). If the code goes away, fine. If not, then you can spend more time diagnosing it (with good reason to believe that it is not the O2 sensor).

 

[Harpua216]

i would also check for potential exhaust leaks around your catalytic converters. two of those codes popped for me on my 92 when one of mine cracked and needed a bead.

edit: i think O2 sensor is on the passenger side cat.

 

[FR-425]

This series of codes indicate a bad Throttle Position Sensor.

Lean switching needs to happen at a specified rpm and throttle position.

If the TPS is so far out of wack in that range no switching will occur because the throttle position does not match with the rpm and the codes are set.

Your code list doesn't jive either as some are KOEO and one is KOER only.

You can't do KOER with a the paper clip method.

It's not a good plan to begin trouble shooting with bad info!!!....

Clear the codes and drive it and see if you get different codes.

Get a proper scan tool, their cheap these days.

Fault codes 101.

1. Always trouble shoot the list in the order they appear. ( this is another problem with the paper clip.) you are getting codes in numerical order not from first to last.

2. Faults codes do not automatically mean that the sensor related to the fault description is faulty.

 

[malohnes]

This series of codes indicate a bad Throttle Position Sensor.

Lean switching needs to happen at a specified rpm and throttle position.

If the TPS is so far out of wack in that range no switching will occur because the throttle position does not match with the rpm and the codes are set.

Your code list doesn't jive either as some are KOEO and one is KOER only.

You can't do KOER with a the paper clip method.

It's not a good plan to begin trouble shooting with bad info!!!....

Clear the codes and drive it and see if you get different codes.

Get a proper scan tool, their cheap these days.

Fault codes 101.

1. Always trouble shoot the list in the order they appear. ( this is another problem with the paper clip.) you are getting codes in numerical order not from first to last.

2. Faults codes do not automatically mean that the sensor related to the fault description is faulty.

Fantastic advice - Fault codes 101!!!!