Car has weird idle issues. Sometimes it will idle at like 2-3k, sometimes it's totally normal. Sometimes it bogs and almost dies. Seems sporadic and spontaneous. Seems like it would be a TPS issue, but I just got a new TPS like 2-3 months ago.

The CELs are P0102 and P0138.

P0102 - MAF low voltage
P0141 - O2 sensor heater malfunction (Bank 1, Sensor 2)

I've tried cleaning my MAF already.

Isn't that CEL referring to my 2nd o2 sensor? Why would that affect the idle? I thought that was just to see if the catalytic converter was functioning properly?

Please help..

 

I'm starting to believe that our o2 sensors are actually reversed from the ECU. I think the ECU believes the first o2 sensor is the 2nd o2 sensor.

... or at least calls the code off wrong.

 

You can check the circuit heater with a multimeather for continuity and and Ohms test. At ambient temperature, it should read less then thirty Ohms.

 

But being a heater concern wont effect your idle or anything really. Especially on that sensor. It could cause readings to be slightly off in the first 20 seconds or so but shouldnt make any difference on the rear sensor.

 

<div class='quotetop'>QUOTE (zoned019 @ May 27 2008, 06:13 PM) <{POST_SNAPBACK}></div><div class='quotemain'>The CELs are P0102 and P0138.

P0102 - MAF low voltage
P0141 - O2 sensor heater malfunction (Bank 1, Sensor 2)</div>
So which code is it? P0138 or P0141? The indicated possible causes are slightly different for the two codes.

 

Oops.

It's definitely P0141.

I just replaced the front o2 sensor btw.

Yamaha, which wire do I test?

I ordered a new MAF today, we'll see if that fixes anything. I read somewhere that these two codes go together. But, I'm like 1 of 3 people to ever have and post about P0102. The other guy had 2 replies in his thread, and no conclusion. mad.gif

 

Installed the new MAF and fixed a bit of the MAF wiring, which seemed to have been frayed.

Reset the ECU, codes went away.

A day later, CEL comes back on.

P0141 still. The P0102 for the MAF is gone.

What do I do to fix this? Is this the upstream or downstream o2 sensor? Is it more probable that it's the wiring, or the sensor itself? Are the upstream and downstream o2 sensors the same (I know they have different part numbers, but are they ACTUALLY different parts)?

This is driving me nuts.

Thanks guys

 

Didn't you have a prior problem with your MAF wiring a long time ago or was that someone else?

If there is no other code being thrown, then the O2 sensor is the culprate. If you have Jay-M's computer diagnostic tool, then troubleshooting the problem is easy. put up a graph of your sensor and then you'll be able to tell if it's bad.

If you think the problem is with the wiring, then my favorite method to test a questionable wire is to pull back the wire loom, stick a pin or a wirestab multimeter tip into the wire and then ohm it out from the connector to the place your stabbing. You should read 0 ohms maybe 1, but no more then 1 ohm. When you get done stabbing the wire tape it with electrical tape to maintain the consistancy of the wire shielding.

 

He already replaced the MAF. That code is gone now.