Some valve lift systems report back where the rocker arm actuator actually is, rather than relying on oil pressure; continuously variable designs driven by an electric motor, such as Toyota Valvematic, work this way. P264A is the general circuit fault for the position sensor of actuator A on bank 1: signal missing or implausible without a clear low or high pattern. No manufacturer documents this code publicly with thresholds; Toyota's Valvematic bulletin T-SB-0098-19 files its sensor fault under the B sensor code P265B. CARB demands monitoring of all electrical parts of such systems. Without valid feedback the controller usually freezes lift at a safe value, costing power and fuel economy.
Medium severity. Can I keep driving?If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.
Bank 1 is the side of the engine with cylinder 1. Inline engines only have this bank.
Symptoms
- MIL on
- Lift held at a fixed value, less power
- Higher fuel consumption
Most likely causes
- Loose or corroded position sensor connector
- Damaged signal, supply or ground wire
- Position sensor failed internally
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: hard
- It can trigger limp mode.
- It affects emissions.
What each character of P264A means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- 6: Control modules and outputs
- 4A: Specific fault in that system
Frequently asked questions
Can I keep driving with code P264A?
If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.
What causes code P264A?
The most common causes are: loose or corroded position sensor connector; damaged signal, supply or ground wire; position sensor failed internally.
Related codes
- P264B"A" Rocker Arm Actuator Position Sensor Circuit Range/Performance (Bank 1)
- P264C"A" Rocker Arm Actuator Position Sensor Circuit Low (Bank 1)
- P264D"A" Rocker Arm Actuator Position Sensor Circuit High (Bank 1)
- P264E"A" Rocker Arm Actuator Position Sensor Circuit Intermittent/Erratic (Bank 1)
- P2645"A" Rocker Arm Actuator Control Circuit/Open (Bank 1)
- P266A"A" Rocker Arm Actuator Position Sensor Circuit (Bank 2)
- P265A"B" Rocker Arm Actuator Position Sensor Circuit (Bank 1)
Sources
- law.cornell.edu: 13 CCR 1968.2
- static.nhtsa.gov: MC 10164873 9999
- en.wikipedia.org: Variable valve lift
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.