P264D: "A" Rocker Arm Actuator Position Sensor Circuit High (Bank 1)

With P264D the position signal of actuator A on bank 1 reads above its plausible maximum. An open ground return, a signal line touching the 5 V or battery feed, or water in the connector can push it up. Because a reading at the upper stop looks like an impossible position, the controller rejects it and runs a fixed lift. No public manufacturer documentation gives a threshold; the regulatory basis is CARB's demand to check every input of a variable lift system for out-of-range values. Toyota's Valvematic engines show that such feedback exists, though Toyota files its sensor faults under the B codes. Compare with P264C (low) and P264E (intermittent).

Bank 1 is the side of the engine with cylinder 1. Inline engines only have this bank.

Symptoms

• MIL on
• Engine runs on a fixed lift setting
• Noticeably less power

Most likely causes

• Open sensor ground
• Signal wire shorted to 5 V or battery voltage
• Water ingress in the sensor connector

What to check, in order

Start with the simplest. You can tick off each step.

1. Check the battery, connectors, and wiring
2. Check the sensor's ground and make sure the signal wire is not receiving voltage from another circuit.
3. Read the live data with a scanner
4. Follow the manufacturer's service manual

Good to know

• Repair difficulty: hard
• It can trigger limp mode.
• It affects emissions.

What each character of P264D means

• P: Powertrain: engine and transmission
• 2: Generic code: same on every make
• 6: Control modules and outputs
• 4D: Specific fault in that system

Frequently asked questions

Can I keep driving with code P264D?

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 P264D?

The most common causes are: open sensor ground; signal wire shorted to 5 V or battery voltage; water ingress in the sensor connector.

Related codes

• P264A"A" Rocker Arm Actuator Position Sensor Circuit (Bank 1)
• P264C"A" Rocker Arm Actuator Position Sensor Circuit Low (Bank 1)
• P266D"A" Rocker Arm Actuator Position Sensor Circuit High (Bank 2)
• P265D"B" Rocker Arm Actuator Position Sensor Circuit High (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.