P1259 on Acura: How to Diagnose & Fix
VTEC System Malfunction (Honda)
1 Acura model · 1 documented issue · $70-$250 repair
P1259 on Acura by model: symptoms, diagnosis and fix
The VTEC oil pressure switch screwed into the VTEC solenoid assembly on B18C engines fails or leaks, triggering CEL with OBD1 Code 22 or OBD2 P1259. Symptoms include VTEC not engaging at high RPM and a hard rev-limiter drop. One 1999 GS-R owner reports the code returning even after replacing the switch and the VTEC solenoid, typically after entering VTEC and lifting off at around 60-90 mph.
Common Symptoms
- check engine light
- VTEC fails to engage
- soft rev cut around 6000 RPM
- loss of top-end power
How to Fix
Check the oil level and condition first; make sure there is plenty of oil, then reset the ECU. If the code is still present, replace the switch — it is the green-plug sensor on top of the VTEC solenoid; use the OEM Honda part (about $70). If the code returns after replacement, install a mechanical oil pressure gauge: a worn oil pump or internal leak can cause low pressure that triggers the code.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- VTEC valve-timing oil-pressure switch 37250-PR3-003
Verified repair fluid. Approved replacement: VTEC valve-timing oil-pressure switch 37250-PR3-003.
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Owner tips & cautions
- TipDo an oil and filter change before replacing the switch — gunked oil galleries often cause the same code.
- WarningAftermarket VTEC controllers commonly trigger this code by changing the engagement RPM the ECU expects.
Sources for this issue (2)
P1259 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P1259 mean on a Acura?
P1259 stands for "VTEC System Malfunction (Honda)." This Honda-specific code indicates a malfunction in the VTEC (Variable Valve Timing and Lift Electronic Control) system, the technology that switches between different camshaft profiles to boost performance at higher RPM. The system uses an oil-pressure-controlled spool valve and a pressure switch to engage VTEC, and the engine computer monitors whether the commanded change in valve operation actually occurs. The code sets when the computer detects that VTEC engagement or oil pressure is not matching expectations. It commonly causes reduced high-RPM power and a check engine light, and is frequently tied to oil level or oil pressure problems. On Acura it is documented across 1 model: Integra.
What are the most common causes of P1259?
The most common causes of P1259 are: Low engine oil level or low oil pressure, Faulty VTEC solenoid or clogged solenoid screen, Faulty VTEC oil pressure switch, Dirty or degraded engine oil, Wiring or connector fault at the VTEC solenoid or switch, Sticking VTEC spool valve, Faulty engine control module. The specific cause varies by vehicle.
How much does it cost to fix P1259 on a Acura?
Published repair estimates on Acura range from $70 to $250 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.