Roofmaster

Sorry to have to ask but I need the codes for my 95 4x4 pickup.21 abd 27.Im pretty sure the 21 is the pre cat o2 sensor.Not sure about the 27.Thanks guys.

brianh699

I don't have an FSM for a 95 but the 93 FSM shows no code 27 for the 3vze(I'm assuming that's what engine you have) there is a code 27 for the 22re and it's the second oxygen sensor code which is only on california vehicles. The 95 may have this though code 27 is definitely for second oxygen sensor. 3vze codes http://personal.utulsa.edu/~nathan-b...85diagnosi.pdf
22re codes http://personal.utulsa.edu/~nathan-b...26diagnosi.pdf

Roofmaster

I broke the pre cat O2 sensor about a month ago and its been hanging waiting to be fixed.I also have an after cat sensor so that must be the code 27.Ive slacked on fixing the other sensor because I broke it at the bung.How bad is it to run the truck with a broke sensor,or 2 for a few more days till I can get under there?Thanks again.

brianh699

You should be OK running without the oxygen sensor, ECU will run in closed loop with preset values. It won't be using readings from the sensor since they are out of spec. It may run a little rough.

Roofmaster

I'll get under there and replace them Sunday.I already bought one.Thanks guy.