redlion4

Trying to help out a friend of the family with their 2002 Civic EX. I am fairly versed in working on them as I own a 2005 Civic LX SE, with the Honda service manual as I do 98% of my own maintenance - from oil to timing belts. My skills and tool set usually stop at the tranny . The problem car and background:

2002 Civic EX with ~225,000 miles
Little to no input on conditions that triggered the P1259 code (teen girl driver).
Oil level is spot on.
Oil pressure switch continuity is good (step 8, page 11-153)
Oil pressure switch connector checks out fine (steps 10 & 15, on pages 11-153 & 11-154)
VTEC solenoid connector checks out fine (step 18, page 11-154)
Cannot perform step 19, as I lack the pressure tools...have not gone beyond this point.

The twist - the code immediately re-triggers when cleared, even when the car is not running. Yep, the scan tool clears it, the CEL goes out, then 5-10 seconds later the CEL turns on again. Same results if/when the code is cleared and the car is running at idle. No need to do steps 3 + 4 (the road test)...the CEL won't stay cleared and always reports P1259.

Does this point to ECM issues rather than the VTEC assembly? Or is the VTEC solenoid possibly damaged or stuck? I have not yet removed the VTEC to inspect and clean the screen, switch, and solenoid. Told the family I could do that this weekend.

Looks like the VTEC assembly sells for ~$145 - $155, plus shipping. If the CEL would stay off while the car is not running I would be more confident ordering the part (15810-PLR-A01). Wanted to get more input though given the strange triggering of the CEL / P1259 when the car is not running...!

Thoughts?

Matt_75

Never mind what I posted. You had voltage at step 10.

Hopefully ezone will chime in.

ezone

I don't think I have chased this particular situation, but.....


If it resets without the engine running, you can eliminate half of the tests. Concentrate on the ones that would make a difference without the engine running.
There is no oil pressure if the engine isn't running, so it will NOT matter if the valve itself is stuck right now.

You have a switch, wiring, or PCM issue.
My guess is that the PCM sees the pressure switch (wrong voltage reading for whatever reason) in the wrong state (open) with low oil pressure.
The wire the PCM reads isn't getting grounded when it should be. (or the PCM can't see it)

Switch should have continuity at rest,
Steps 9, 10, 15--you have 12 volts at step 15?
14-30 ohms at step 18? (I don't think this is actually monitored by the PCM for resistance, so it should have zero effect until the PCM attempts to activate the valve).


I'd put a jumper wire across the connector for the switch and see if that keeps the code from popping back right away.

Then, depending on the results of that,
(code stays off) check terminal fit on the switch pins
or
(code returns right away) maybe go to the PCM wiring and test there.
Backprobe terminal B-9 with the key ON, should show as grounded with the engine OFF.
Unplug the switch, should show 12v.
This should give a definite answer as to what the problem is, you just have to figure out where.

I see a lot of rodent damage to wiring in the engine compartment here.


HTH

ezone

Now that I thunk about it....
I have chased this, and it was rodentized wiring.

redlion4

Yeah, that is what I was afraid of. Thanks for the responses!

Yep, oil pressure switch has continuity. Oil pressure connector reads 12+ volts with the ignition turned on. VTEC solenoid connector measures 16.5 ohms.

It is a salvaged vehicle, previously involved in a front passenger corner/side accident. Would not surprise me if some of the wiring/covers/plugs were compromised from the accident and repair. Told them I would be glad to work on it, but the car would need to be parked in my garage for a while so I could take my time testing and tinkering. This would be the first time I had to probe PCM wires - I can't be rushed.

They elected to take it to the shop instead. I did my best to warn them not to let the shop (generic mechanic, not Honda) swap out the VTEC assembly based on the P1259 code that re-triggers even when the car is not running. We'll see how it goes...what the shop finds and what it costs.

Thanks again for the input.