OBD-II Diagnostic Trouble Code
P2670 — A Rocker Arm Actuator Position Sensor Circuit
The ECM detected an electrical fault in the position or feedback sensor circuit for the 'A' rocker arm actuator. This sensor confirms the switched state of the valve lift or deactivation mechanism. Some code lists use P2670 for an actuator supply voltage circuit instead, so check the OEM definition for the vehicle.
Severity 3/5
Truck-relevant
Service this week
Severity
Service this week
A Rocker Arm Actuator Position Sensor Circuit
Code
P2670
Category
Powertrain
Subsystem
Ignition
Truck-relevant
Yes
What this means for truckers
Service within a few days on a Cummins X15, Detroit DD15, PACCAR MX-13. Performance is likely degraded. Continuing to drive without service risks additional component damage.
Before you replace parts — try this first
P2670 on the Ignition system is most often damaged or corroded wiring or connector to the sensor — not a dead part. On commercial diesels especially, work these in order before spending money on parts:
- Confirm the symptoms. Match what your truck is doing to the Symptoms section below. If the code is set but the symptoms are not there, clear the code and re-test after a drive cycle — it may not return.
- Clean and dry the sensor connector. Water, road salt, or oil seeping into a connector is the #1 fake sensor failure. Disconnect, look for green corrosion or moisture, spray with electrical contact cleaner, dry, reseat. Many faults clear here for $0.
- Inspect the wiring harness. Trace the wire from the sensor toward the ECM — look for chafing against the engine block, melted insulation near the turbo or exhaust, or pinch points where a clamp has rubbed through.
- Test the sensor before swapping it. Most Common Causes (below) list the expected voltage or resistance range — a $20 multimeter saves a $300 sensor swap that does not fix the problem.
- Only then, replace the part. Use the OEM or a tier-1 aftermarket. Cheap sensors throw the same code in two weeks.
Symptoms
Check-engine light, possible reduced performance, and the valve lift system may default to one mode. There is usually little drivability impact.
Common causes
- CommonDamaged or corroded wiring or connector to the sensor ($80–$300)
- CommonFailed position or oil pressure sensor ($80–$300)
- OccasionalSupply voltage or reference fault ($80–$350)
- RareECM fault ($800–$2000)
How to fix
Confirm the OEM definition for this code on the vehicle
When to use: First step
Check reference voltage, ground and signal at the sensor
When to use: To isolate the sensor from the wiring
Repair the wiring or connector
When to use: When a circuit fault is found
Replace the sensor
When to use: When the circuit is good
Affects most
No specific vehicle pattern found in our complaint database. This code can appear on any vehicle that supports OBD-II diagnostics.
Related
Frequently Asked Questions
Can I drive with code P2670?
P2670 is severity 3 — plan service within a few days. Performance is likely degraded already (you may feel reduced power, harsher shifts, or slightly worse fuel economy). Continuing to drive risks additional damage to adjacent components.
How much does it cost to fix P2670 on a commercial truck?
Total repair cost ranges $80–$2000 depending on the root cause. The cheapest fix is usually the first one listed below — Damaged or corroded wiring or connector to the sensor — which is also the most common. On commercial trucks the cost is usually higher than passenger vehicles due to part availability and shop labor rates ($120–185/hour at most truck shops, vs $90–130 at general auto shops). DIY-capable fixes (sensors, hoses, filters) are at the low end; major component replacements (turbo actuator, high-pressure fuel pump, transmission solenoid pack) are at the high end. Always diagnose with a scan tool BEFORE replacing parts — guessing wrong on a $1,500 turbo actuator when the actual issue was a $30 boost hose is a common expensive mistake.
Will P2670 fail a DOT inspection?
P2670 is generally not a direct DOT inspection fail item by itself. Inspectors focus on safety-critical systems (brakes, steering, tires, lights, hours-of-service). However, the check engine light alone can trigger additional inspection scrutiny. Best practice: fix the code and clear it before a planned inspection.
What's the difference between P2670 and related codes?
P2670 is closely related to: P2647 (A Rocker Arm Actuator System Stuck On (Bank 1)). These codes share the same subsystem (ignition) and often appear together. If you see this code, scan for the full code list — fixing the root cause usually clears multiple companion codes at once. If only P2670 is set without the companions, the issue is more isolated.
How do I prevent P2670 from coming back after a repair?
For P2670 (A Rocker Arm Actuator Position Sensor Circuit), prevention centers on the ignition system. Use OEM-spec injectors and spark plugs (gas). Address fuel quality issues immediately — bad fuel kills injectors. Cylinder balance test annually for early warning.