Code
P264D
Generic
P — Powertrain
A Rocker Arm Actuator Position Sensor Circuit High Bank 1
AI status
Completed
Completed
100%
Causes
- Short to battery voltage in sensor signal wire
- Faulty rocker arm actuator position sensor (Bank 1)
- Poor or corroded connector or terminal
- Open or damaged wiring causing incorrect reference voltage
- Bad ground at engine/PCM
- Low or contaminated engine oil affecting actuator operation
Symptoms
- Malfunction Indicator Lamp (MIL) / Check Engine Light ON
- Reduced engine performance or rough idle
- Loss of variable valve timing control, possible limp mode
- Decreased fuel economy
- Unusual valvetrain noise if actuator mechanically affected
- Hard starting or stalling in severe cases
What to check
- Scan vehicle and record freeze-frame and live data for the sensor
- Verify battery voltage and charging system health
- Visually inspect sensor connector and wiring for damage, corrosion, or oil contamination
- Backprobe sensor signal and reference wires with ignition ON (engine off) and note voltages
- Check continuity and resistance of signal, power, and ground circuits to the PCM
- Inspect engine oil level and condition; check for metal debris or sludge
Signal parameters
- Expected sensor signal type: position voltage or hall/analog (manufacturer-specific)
- Typical analog voltage range: about 0.0–5.0 V (exact range varies). A 'High' code often means signal >4.5–4.8 V or equal to battery voltage
- Reference/test voltage (if present): ~5 V or ignition-switched 12 V feed depending on sensor design
- Ground should be near 0 V; high resistance or open ground can elevate the signal
- If hall-type: may output a fixed high level when faulted; check for pulsed or steady signal in live data
Diagnostic algorithm
- Connect a scan tool and confirm P264D, review freeze-frame and live data for Bank 1 rocker arm position sensor.
- With ignition ON (engine OFF), backprobe the sensor connector: measure signal, reference/power, and ground. Compare to expected ranges. If signal is high (>4.5 V) with ignition ON, suspect short to 12 V or internal sensor failure.
- Inspect connector for corrosion, oil intrusion, bent pins, or water. Repair or replace connector/terminals as needed.
- Wiggle test wiring while monitoring live signal for intermittent shorts or opens. Repair any damaged harness sections.
- Verify continuity between sensor signal wire and PCM pin; check for shorts to battery voltage and to ground. Repair wiring faults.
- Check engine grounds for tightness and corrosion at ground points; clean and torque as required.
- If wiring and connectors are good, replace the rocker arm actuator position sensor/actuator assembly for Bank 1 per manufacturer procedure.
- If problem persists after sensor replacement, test or swap with known-good sensor (if practical) to isolate PCM vs sensor.
- Inspect oil level and quality; change oil/filter if contaminated. Some actuators require clean oil to operate and electrical connectors can be affected by oil contamination.
- After repairs, clear codes and perform road test and re-scan to confirm the fault is corrected.
Likely causes
- Corroded/loose connector at the sensor
- Damaged sensor signal wire shorted to +12V
- Failed position sensor inside rocker arm/actuator
- Poor ground at engine harness or sensor
- Oil contamination or mechanical seizure of actuator
Fault status
Status
PCM detected abnormally high voltage on Rocker Arm Actuator Position Sensor circuit (Bank 1).
Repair difficulty: Medium
Diagnostic time: 0.5-3.0 hours
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