P1259 code and cannot figure out why!

2168 Views 7 Replies 4 Participants Last post by TedR, Jun 25, 2021

MoTreez

Discussion Starter · Jun 23, 2021

I have a 2002 RSX type s (k20a2). I recently bent a valve so I replaced the valves and everything else that got damaged. After getting the motor put back together the shop I brought it to said everything checked out and I could come get it.. I pick it up and drive it about an hour or so back to my house.. I had not engaged vtec the entire time.. I get about 3 miles from my house and the CEL comes on and my car goes into limp mode.. I get it scanned and get a P1259.. I unplug my ecu to reset it take it down the street and crack vtec.. I left the next day to go back to the shop and again CEL comes on.. I plug in my kpro and cel comes on for P1259 so I clear it and then hit vtec and I noticed it feels like it cuts out almost during the engagement.. every time engaging vtec I eased into it I NEVER mashed the pedal.. Ive since then put my stock ecu in and switched out the entire solenoid, went and took it for a drive and had no vtec at all.. I drove it around to give it a chance to pick up a code and no CEL comes on just no vtec engages... I noticed before switching the solenoid vtec would only engage like 1-3 times before throwing the CEL and going into limp mode.. I’m super stuck on what it could be so ANY and ALL possible leads/advice is much appreciated

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jr_deleon

· #2 · Jun 23, 2021

There are several things that could be at play here, but if everything was in working order before you dropped it off, the first thing I’d check is your oil level. You’d be surprised how many people have had a VTEC system code only to find that there was not enough oil in the engine. Did you notice any grime or shavings on the spool assembly screen when you replaced it (sits within the spool assembly o-ring)?

Not saying this is the case, but if they missed one of the roller pins that engage VTEC that could also cause problems, not just because of the mechanical nature of the system but with a pin missing the pressure in the system would drop.

There are also dedicated tests in the service manual if there is the appropriate amount of oil in the engine. The tests check the functioning of the switches and solenoids in the system. That could be another avenue as well.

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MoTreez

Discussion Starter · #3 · Jun 23, 2021

jr_deleon said:
There are several things that could be at play here, but if everything was in working order before you dropped it off, the first thing I’d check is your oil level. You’d be surprised how many people have had a VTEC system code only to find that there was not enough oil in the engine. Did you notice any grime or shavings on the spool assembly screen when you replaced it (sits within the spool assembly o-ring)?

Not saying this is the case, but if they missed one of the roller pins that engage VTEC that could also cause problems, not just because of the mechanical nature of the system but with a pin missing the pressure in the system would drop.

There are also dedicated tests in the service manual if there is the appropriate amount of oil in the engine. The tests check the functioning of the switches and solenoids in the system. That could be another avenue as well.

I forgot to mention that I did check the oil and it was full.. when I got the head back from the machine shop literally ALL of my pins and springs were missing but only had enough to put 1 rocker arm assembly back together.. I then bought 8 rocker arm assemblies off eBay that I was told the rocker arms came off a k20a2.. I had all the pins and springs put back in.. could it be possible the pins and springs are in wrong?

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Lotus

· #4 · Jun 23, 2021

VTP sensor plugged in?
Run a data log in the KPro. You should see when MIL is activated and when the VPT sensor is triggered. You could also disable VTP to engage VTEC for a check.

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MoTreez

Discussion Starter · #5 · Jun 23, 2021

Lotus said:
VTP sensor plugged in?
Run a data log in the KPro. You should see when MIL is activated and when the VPT sensor is triggered. You could also disable VTP to engage VTEC for a check.

Yes.. everything is plugged in.. besides checking the oil level that was the other thing I checked out first.. when I plugged my kpro in before I swapped solenoids the only error code was the P1259 and then in “()” it said “(oil pressure switch)” but that’s the only code I get.. I’ve been having people tell me it’s the oil pump but I was under the impression if it was the oil pump I’d have significant power loss and probably more than just a vtec code.. which I don’t have any power loss at all.. if anything the car feels a lot more healthier now besides vtec not working properly

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Lotus

· #6 · Jun 23, 2021

I talk about the VTP sensor, not the switch for the oil lamp. Some looms don’t have the cable and plug for it, e.g. K20a from the DC5

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MoTreez

Discussion Starter · #7 · Jun 25, 2021

Lotus said:
I talk about the VTP sensor, not the switch for the oil lamp. Some looms don’t have the cable and plug for it, e.g. K20a from the DC5

I’m not sure then.. I just know all the plugs from the harness are plugged in where they are supposed to go

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TedR

· #8 · Jun 25, 2021

Remove the vtec solenoid and make sure the screens are clear. Assuming they are clean, or you clean them and still have an issue, replace the oil pressure switch next to the solenoid.

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