O2 sensor where is the location of the secondary o2 sensor on an 88 honda prelude

96's are kinda the bad year for our cars being the only obd2 4th gen preludes so for any codes over 43 you have to look it up in the '97-'01 manual. Code 65 is "Secondary Heated Oxygen Sensor Heater Circuit Malfunction (Sensor 2)". Probable causes are an open in the secondary O2 sensor heater circuit or bad ECU. Have you tried resetting the ECU to see if it comes back? If so, you could check for loose wires coming from the secondary O2 sensor in the cat converter going to the 4 pin connector, or if you have access to another ECU I would try to substitute a known good ECU to see if that clears it up. The troubleshooting flowchart is on page 11-79 in the '97-'01 helms manual, and involves checking resistances and for continuity.

I think this could be the code I had on my '96 when I bought it. I tried replacing the secondary O2 sensor, and long story short it was the ECU. Luckily my '96 was still under the extended emmissions warranty, so Honda replaced it for free. I don't think you would be covered under the extended warranty because it was 14 years and under 150k miles. I just barely made it (within a month or 2 and 3k miles) last year.

As far as the engine sounds and rough idle, you could just need a valve adjustment. The secondary O2 sensor just checks the cat to make sure it's working right.

And all auto trans want to move forward when the brake is released.

simply unplug and use a 7/8 wrench and a lot of muscle use a small amount of anti seize during installation.

Is it your primary or secondary O2 sensor that's failing? The secondary is just there to check that the cat is working, and shouldn't impact your gas millage. (My 97 Honda Prelude always threw a secondary O2 reading too high or too low because the cat was gutted). If it's the primary, have someone double check the actual wiring harness for the O2. The EL should use a heated O2 sensor.. which have a heater element in them to warm them up faster so they read accurate sooner. The heater wires may not be functioning, or the wire in the harness for the O2 signal may be damaged or pinched.

the fuel pump is in the gas tank

http://www.car-stuff.com/repairmanual.htm

You need to check the tcm for codes too. The s3 light is like the check engine light for the tcm. The VSS code might be your problem.

SECONDARY HEATED O2 SENSOR HEATER CIRCUIT FAULT SENSOR 2.

6
Accord Civic CRV CRX Del Sol Odyssey Prelude
85-98 86-98 97-98 85-91 93-97 95-98 85-98 ECT Sensor (Engine Coolant Temperature)
defective circuit or unplugged / defective sensor
10
Accord Civic CRV CRX Del Sol Odyssey Prelude
85-98 86-98 97-98 85-91 93-97 95-98 85-98 IAT Sensor (Intake Air Temperature)
defective circuit or unplugged / defective sensor
16
Accord Civic CRV CRX Del Sol Odyssey Prelude
90-95 88-95 n/a 88-91 93-95 95 88-95 Fuel Injector System
defective circuit or unplugged / defective fuel injector

check your wiring for dirty connections or broken wires, you may have wires that are rubbed through or connectors that are not making full contact. you will need an ohm meter and check wires for continuity. a wiring diagram will be needed.

if they both are the 2.0L they are the sme thing.