got the 94 vt running,my idle usto be 1200 and now its 1800,both left/rightside eng light on code 1,replaced both o2 sensors with oem sensors,cleaned connectors,disconnected battery,also cleared with tool that snaps into pcm.its a hard code because it comes on right away for both sides.also checked voltage at o2s and cks high,seems like pcm is telling need more gas at keeping idle higher.vehicle runs strong no drivabilty concerns noticable.
thanks

anyone have the schematics for the 02 sensor wiring and pcm wiring?seems pcms are not recognizing the o2s.ck eng lights come on before the engine starts,its a hard code,any help would be appreciated.
thanks

Are you sure that you have really cleared the codes ?

If you're getting a high voltage across the o2 sensors this would indicate that the car is running rich and would give a code 3. The voltage measured should be from the single wire from the o2 sensor to earth/frame.

One sure way to clear the codes is remove the terminals from the car battery, the battery disconnect switch does not do it.

i had the battery disconnected for hours,also cleared the codes using the connector in the computer and no luck,getting 9 volts to o2 sensor,stuck in rich mode.seems like it has open circuit some where but have no idea where.i do have a used coil on,will get a new one today but i would not think that would cause a o2 concern.

There are three wires that come from each o2 sensor, two together on once snap connector and one on its own. What is the voltage from the one on its own to earth ?

.9 at idle

So the sensors are working, reading a voltage to suggest rich exhaust gases. Yet both computers are sensing inactive o2 sensors, which means a steady voltage of .4 -.5 volts.

What is the voltage across the sensors with the engine ignition on, but the car not running ?

voltage without running is .09.i drove the car 35 miles today and the car ran great did not notice any drivabilty concerns but it is running rich,i took to an independant lambo repair shop.he checked it with a scanner when i arrived and stated its at full rich mode constantly,wil let you know when he finds out.

I just tried this on my car :

1. Cold engine, ignition on, not started voltage across 02 sensors about 0.3v

2. Engine started, voltage starts to move up and down, eventually cycling two or three times a second from about 0.2 to about 0.9 volts

3. Engine stopped, ignition on [engine a bit warm] voltage across o2 sensors about 0.03 volts

4. Allowed engine to cool for 15 minutes, voltage across 02 sensors back at 0.3

I hope this info is of some use.

It is hard to think of anything that could affect both sensors and both computers in exactly the same way.


Could it be that you have the wrong sensors, or have them somehow connected wrong ?

When I changed my sensors last the correct Bosch part no was 0 258 003 957 - 760

When I have had o2 sensors inactive it doesn't make the car run especially rich. Have you tried running it with the sensors disconnected.

Sorry, can't think of anything else, let us know how you get on.

hi mike while car is running disconnected o2 sensors nothing changed.the 02s are the correct ones i got them from lambo dealer and # matches my old ones.for some reason computer is not recognizing the o2s,it thinks there not there.its at a shop now i will wait to hear from then.imay be possibly selling the car after the repair well see what happens.