This thing has been an off and on project for the past two months as I dig through shoddy/incorrect work from the previous owner. I've got the car down to the last two CEL codes that I can't seem to diagnose.

Body is a 99 Civic DX
Engine is a JDM D15B block with D16Y8 head
Harness is from a D16Y7
Throttle body is from a D16Z6
Transmission is from a 95 Civic DX manual.
ECU is an unchipped OBD1 P28 with an OBD2B->OBD1 conversion harness. I still have the stock P2E as well.

Codes from the P2E: 14, 17, 41 (code 14 is from the IACV, which has been converted from 3 wire to 2 wire, to work with OBD1)
Codes from the P28: 17, 41
Code 17 is for the VSS, code 41 is for primary oxygen heater.

Since I get the same codes with two different ECUs running two different OBDs, this makes me think that the problems are not from a faulty ECU. I do not have an OBD2 reader, and retrieved the OBD1 codes using the paperclip trick.

Speed sensor is electronic; the 3 wire connector from the harness hooks right up, but the speed sensor looks like it only has connections for two wires. Speedometer stays at 0 while the car is moving and in gear, and the VSS CEL is thrown.

Oxygen sensors are 4 wire, they look new.
O2 Sensor diagnostics I used: http://home.icequake.net/~nemesis/bl...p/archives/453
Fuse 15 is good.
O2 sensor is receiving voltage from the battery.
~18 ohms of resistance between the two black wires, within the 10-40 ohm tolerance
No internal short in O2 sensor (no continuity)
No apparent wire short between ECU pin A6 and O2 sensor (no continuity)


Looked into this (http://www.tegger.com/hondafaq/tsb/civic/x99-029e.pdf), but the wires around connector C115 were fine and fuse 15 isn't blown.


So, where do I go from here? I've been at this for weeks now and I'm stumped.

 

Is there continuity between the primary O2 sensor plug and ECU connector pin A6?

Is there continuity between the VSS plug and ECU connector pin B10?

 

No continuity between A6/B10 and a body ground, but I'm not sure that's what you're asking.

How would I test continuity between the ECU and the plug? I think that's too far for the leads on my multimeter to reach.

 

This^ tests for a short in the wire, not whether the wire is properly pinned to the ECU.

You can ground one end and test for continuity to body ground at the other end.

 

Thank you, I'll try this first thing tomorrow and report the result.

 

Explain this a little more

 

The male end on the speed sensor looks like it does not have the middle prong to create a connection for three wires. I have three wires coming from the harness to the connector, and the connector fits on the speed sensor, but it looks like only two wires are actually doing anything.

 

It's probably corroded off (very common). If it is you'll need a new one.

 

Did this, but not getting continuity. I think A6 corresponds to the PO2S on OBD2A, but I have an OBD2B harness.

http://www.ff-squad.com/technet/wiri...schematics.gif
This makes me think the PO2S wire is at C1. The wire's description is blk/wht at that position, which matches my ECU plugs.

I tried the continuity test you described at both A6 and C1, but neither have continuity.


Thank you, this was exactly the problem. Will be ordering a new speed sensor soon. One CEL down, one to go.

 

Bumping this.
Should I be looking for a broken wire somewhere since it seems there's no continuity? What's the best way to do that?