[ephc]

hi guys

I'm calling the dealer tomorrow for an appointment, but was thinking maybe the collective Lotus conscience might have some ideas about a CEL I'm getting...
P0138 O2 Sensor Circuit High Voltage (Post Catalyst)
P0141 O2 Sensor Heater Circuit (Post Catalyst)

I haven't noticed any real change in the way the car behaves, but then again, I've only got about 600 miles (1000 kms) logged on the car.

The only thing I've noticed that seems a little off is that the idle is just over 1000 rpms. From what I understand, it should be around 850 or so. The idle hunts slightly based on how it sounds, but the tach needle doesn't move significantly...

Based on the codes, it seems like its just the secondary o2 sensor. The car only has just over 10000 miles (17000 kms). Is this normal? seems like its early for the o2 sensor to go. The car is stock, but I don't know if there were any mods done to the car previously and then returned to stock before I bought it.

Any help is appreciated...

 

[apk919]

hi guys

I'm calling the dealer tomorrow for an appointment, but was thinking maybe the collective Lotus conscience might have some ideas about a CEL I'm getting...
P0138 O2 Sensor Circuit High Voltage (Post Catalyst)
P0141 O2 Sensor Heater Circuit (Post Catalyst)

I haven't noticed any real change in the way the car behaves, but then again, I've only got about 600 miles (1000 kms) logged on the car.

The only thing I've noticed that seems a little off is that the idle is just over 1000 rpms. From what I understand, it should be around 850 or so. The idle hunts slightly based on how it sounds, but the tach needle doesn't move significantly...

Based on the codes, it seems like its just the secondary o2 sensor. The car only has just over 10000 miles (17000 kms). Is this normal? seems like its early for the o2 sensor to go. The car is stock, but I don't know if there were any mods done to the car previously and then returned to stock before I bought it.

Any help is appreciated...

The service manual suggests that you check the O2 sensor connector to see if it's loose or corroded...

 

[charliex]

sounds like a short either in the sensor or wiring.

 

[ephc]

thanks for the advice...i'll check those things out.

 

[jmmorford]

These codes concern the O2 sensor downstream of the cat. This sensor is not part of the feedback loop that controls the fuel/air blend to the injectors. It only reports on the performance of the cat. Malfunction of this sensor will not affect the engine's performance. Any change you have noted has some other cause or is your imagination.

With these codes there are only two things that could be wrong, assuming the sensor and wiring are OEM:
1. Your O2 sensor is shot. This is most likely, particulalry with the P0141 code (which indicates that the heater circuit is bad; they deteriorate eventually); or
2. There is a bad connection in the wiring for the sensor. It is a British car afterall; so this is a real possibility.

The easy fix is to replace the sensor. Don't mess with the generic version available on e-Bay. They are mostly crap (I learned the hard way). Get one from Toyota or pay your Lotus dealer even more.