00_EJ7

Hey guys:

I picked up a 2000 Honda Civic coupe (HX) a couple months ago and recently it's been running like poo poo. Surprisingly, I've had no CELs or stall-outs, just tons of hesitation, jerkiness on the road and poor throttle response. While running some errands, I decided to pull into the AutoZone near my house and have them check for codes. They discovered a plethora of error codes which include the following...

P1259 VTEC System Malfunction
P0122 Throttle Position Sensor Circuit Low Input
P0135 HO2S-11 (Bank 1 Sensor 1) Heater Circuit Malfunction
P1456 EVAP System Leak Detected (Fuel Tank Area)

Thinking that the o2 sensor would probably be the easiest -- and most important -- part to replace, I decided to try and test sensor # 1 with a multimeter for any faulty activity. Let it be stated here and now that my knowledge related to electronics in most respects is SEVERLY lacking (lol). Nevertheless, it was my understanding that o2 sensors come in a few varieties-- one, two, three and four wire connector pieces. However my Civic appears to have a FIVE wire plug and and a completely foreign female plug. I've included some photos of it below.

Is this usual for a Civic with the D16Y5? How do I go about testing the sensor to see if it's faulty?


As a little post script here, I bought this car for its excellent fuel economy numbers and to use as a basic daily driver. Cosmetically, it's in pretty decent shape, it hasn't been modded, almost everything on the car is original (body panels, engine, trans etc.) and even the AC still works. My intention was to clean it up, help it get back on its feet and make it into a charming, road-worthy car again. But with all these problems now staring me in the face -- combined with the fact that its got a bad oil leak underneath and a leaky water pump -- I'm beginning to question whether I should even keep this thing or not.

Anyways, I appreciate your help, guys!

TomCat39

5 wire O2 sensor is a heated wide band O2 sensor which is what the Y5 (vtec-e) lean burn requires.

The 92-95 VX D15Z1 vtec-e motor also requires the 5 wires heated wideband O2 sensor.

You may wish to search for the helms manual. It's getting harder to find but is still manageable. Search for 96-00 civic FSM on google and see if you can find a good download link. Do not do ANY exe files, it should be zip, pdf, rar, tar or 7zip archive format. Anything else is likely a trojan or some malware download manager. The manual is a PDF but may be archived in a zip/rar type file.

The helms manual will be your best friend for testing and diagnosing your car.

eghatch9295

iTrader: (1)

expensive replacement sensor, looks like someone already went cheap aftermarket with it. vtec code (hopefully) is just a gunked up screen on the solenoid. low oil pressure is the other possibility,last and least likely is the solenoid itself being bad.

mk378

With those codes active, CEL should have been on.

When multiple codes are set, clear them and see which reoccur. Those are the ones to pay the most attention.

Make sure the TPS and MAP plugs are not swapped. The one where one of the 3 wires is solid white goes on the MAP. Then test TPS with a voltmeter.

The O2 heater can be tested with an ohmmeter. You will need a diagram to see which two wires are the heater. If heater is open circuit, sensor is bad. The proper sensor is expensive but essential for the HX to run properly.

00_EJ7

Thanks for all your suggestions, fellas. I've gotten a hold of the FSM for 96-00 Civics. Per the manual, code P0135 (the o2 sensor code) shouldn't even appear in a 00 HX coupe with a 5-speed manual. Not sure how to copy and paste from a secured pdf, but here's what the manual states about the code:

P0135 The scan tool indicates Diagnostic Trouble Code (DTC) P0135: An electrical problem in the Primary Heated Oxygen Sensor (Primary HO2S) (Sensor 1) Heater system (Except D16Y5 engine with M/T).

Why would P0135 have shown up when AutoZone scanned the car when, evidently, it's not even related to an HX? lol

Regardless, when P0135 is present, the procedure shown in the manual to test the o2 sensor is with a regular, 4-pin connector... I'll dig a little further and see if I can uncover anything related to a 5 wire connector.

This is quite possibly the original o2 sensor to the car. I've looked-up what an OEM sensor for an HX Civic would look like and both look practically the same. Both my sensor and the new OE sensor are built by NTK, too.You don't even want to know how much the new NTK costs, either!

mk378

Check the ECU number. Someone may have put in a non HX ECU, which isn't going to work very well.

Also the block and head numbers. Do you really have an HX any more?

00_EJ7

Well, I have some disheartening news. I ran out to the car to verify that the ECU is in fact an HX ECU (denoted by the letters P2N in the serial number). What I found was this:


Only one clip holding the kick panel in? Something must be amiss!


It's an EX ECU!

I knew that the block was a Y5 as I've checked it before, but here's a photo confirming that it is indeed the HX VTEC-E block.

The block is stamped "D16Y5". The VIN plate on the transmission matches that of the car, too.

I searched all around the head of the engine, but I couldn't find any markings indicating that it's a Y5 head. Where would they be located exactly? Sorry, I'm new to Civics!
While I was under there, I snapped a photo of something that has had me perplexed since I bought the car.



Where is the VTEC Solenoid??

TomCat39

Using this post might help:
Please post head codes from your Honda engines here

The head casting stamp is between the exhaust tubes and in your case, right below the valve cover as can be seen in some of the pics of the thread I posted above.

It appears the Y5 Head should be a P2J head casting stamp:

D16Y5
96 HX 5spd---------------------------------P2J-7
98 or 99 HX--------------------------------P2J-6 (Year Code 9/8)

00_EJ7

More good news. I popped the hood to check the numbers and here's what I found.

It's a D16 head off an automatic 2000 DX!
That explains why there's no VTEC solenoid.

I have no evidence to support this theory, but what I surmise is that one of the previous owners probably didn't keep an eye on maintenance, ignored replacing the timing belt on time and ruined the original HX head. What a shame.

I'd like to do a compression test, but the spark plug wire on cylinder #1 seems to be entirely opposed to that proposal -- the spark plug wire is practically glued inside the spark plug hole.

I think I might just give up on this poor little car. I bought it knowing it needed a water pump (and one might as well throw a timing belt on while you're in there), but buying an ECU AND a cylinder head weren't in the original budget. And that's assuming that there's no damage to the pistons if the timing belt did in fact snap.

Such a shame because from the outside it's such a clean little car. Oh well. ; (

Originally it was a Texas car. As such, there's virtually no rust.

eghatch9295

iTrader: (1)

dont be a vagine. the ecu and head for this car cost less than the correct oxygen sensor. if you were going to do a water pump anyways, what's a head swap?