98greensi

hello, i have a 97 stock hatch with a d16y7 a couple weeks ago cel 65 came on while driving for no reason the secondary o2 is good. the car had a header/cat which i swapped with a buddy for the stock manifold/cat he had no cel and once i put the exhaust on and started my car cel came on, code 65 again. now this is with his o2 sensor and cat which worked perfect hours before this and my old sensor now in his car with the header/cat works fine with no cel.

i have reset the ecu a few times, and within 15 seconds of the car starting the cel comes on for code 65. i have no exhaust leak. today i reset the ecu unplugged the o2 and same thing within 15 seconds the cel came on for code 65. does anyone have any ideas whats going on? is it possible i just got a short all of sudden? and does anyone have a ecu pin diagram for a 97, i have searched and only found it for eg's thanks

98greensi

any honda mechanics out there got any ideas?

ifIexplode

Check the wires on the wire harness for the car directly after the connector for the secondary O2 sensor. Im willing to bet one or two of the wires are either broken/burnt completely or are about to. If so, Solder/heat shrink and clear code.

98greensi

thanks, thats what i'm thinking too but i would like to take my ohm meter and go from the plug to the ecu and check for continuity before cutting up my wiring harness. does any one have a 97 ecu pin diagram?

ifIexplode

Here is the PIn outs for 96-98

http://www.phearable.net/tech/wiring...schematics.gif

You dont have to cut up your harness, Just inspect if any of the wires are burnt or cut. IF so you can just solder and heat shrink them. Im just sayin cause the same thing happened to me a long time ago.

98greensi

Alright so i have an update. hopefully someone has an idea because at this point i'm stumped. I'm going to try another ecu tomorrow. the car is still only throwing code 65

went out today and with the pin diagram that iflexplode (thank you) posted i checked for continuity between the o2 plug (nearest to the sensor) and the ecu i found that i had 0 ohms of resitance for

connector A pin 5
connector D pin 13
connector D pin 15
and the last wire (black with yellow stripe) went to ground, i could not find it on the diagram so i assumed that it was suppose to go to ground. i also grounded my volt meter and checked for voltage on the connector D pin 14 (SHO2S-secondary heated O2 sensor) and it was around 0.4-0.6. i thought maybe the sensor was getting old and was operating slow so i replaced it with a brand new bosch reset the check engine light, started the car and same thing within 15 seconds cel code 65 came back on.

Does anyone have any ideas?

thanks in advance.

98greensi

morning bump

Former User

The circuit diagram (taken from the service manual) for the secondary O2 sensor is shown below. The sensor has four wires, two for the O2 sensor itself and two for the heater element of the O2 sensor. Code 65 indicates a specific problem with the heater element so you only need to concern yourself with those two wires.



The O2 sensor wires (ignore these wires for code 65):
1. Wht to Wht/Red wire pins to ECU D14.
2. LtGrn to Red/Yel wire pins to ECU D13.

The heater element wires:
3. Blk to Blk/Yel wire that gets power through dash fuse 15 should have battery voltage with the key in ON(II).
4. Blk to Blk/Wht wire pins to ECU A5.

The following three tests are done with all ECU connectors plugged in and the secondary O2 sensor unplugged:
a) Is fuse 15 blown?
b) With key in ON(II), do you measure battery voltage between terminal 3 (+) and terminal 4 (-) in the O2 sensor wire harness connector?
c) With key in ON(II), do you measure battery voltage between terminal 3 (+) and engine ground (thermostat housing) in the O2 sensor wire harness connector?

98greensi

Thank you for the help, everything came back right. so i went to the scrap yard and got a new plug, now it works. guess it just wasn't making a good connection. even though i got good readings with the meter