P2674 – Actuator Supply Voltage “D” Circuit Low

System: Powertrain | Standard: ISO/SAE Controlled | Fault type: Circuit Low

Definition source: SAE J2012/J2012DA (industry standard)

DTC P2674 indicates the powertrain control system has detected an electrical “circuit low” condition on the Actuator Supply Voltage “D” circuit. In practical terms, the module expected a stable actuator supply feed but measured it lower than intended for the operating conditions. This is an electrical-fault description, not a confirmed failed part. The specific actuator(s) powered by supply “D,” the circuit routing, and the exact enable conditions for running the monitor vary by vehicle, so always confirm pinouts, fusing, splice locations, and test procedures in the appropriate service information. Diagnosing P2674 is typically about finding where voltage is being lost (short-to-ground, excessive resistance, or an open on the feed side) under real load.

What Does P2674 Mean?

P2674 means the control module has identified that the Actuator Supply Voltage “D” circuit is operating at a low electrical level when it should be within the expected range. The definition is strictly “Actuator Supply Voltage ‘D’ Circuit Low,” which points to a supply feed used to power one or more actuators (exact devices vary by vehicle). As a SAE/ISO-structured DTC, the code communicates a standardized fault type (low input) rather than naming a specific component failure. The correct interpretation is that the module detected insufficient voltage on that supply circuit during monitoring, requiring circuit-level testing of power, ground integrity, wiring, and connectors associated with the “D” actuator supply.

Quick Reference

• Subsystem: Actuator supply power feed “D” circuit (power distribution to one or more actuators; exact loads vary by vehicle).
• Common triggers: Short-to-ground on the supply line, excessive resistance at a connector/splice, weak feed through a fuse/relay, or a loaded circuit pulling voltage down.
• Likely root-cause buckets: Wiring/connector issues, power feed faults (fuse/relay/splice), ground problems affecting the supply, actuator internal fault causing excessive draw, control module driver/monitor circuit concerns.
• Severity: Often moderate to high; may cause reduced performance, disabled functions, or a no-start/no-run depending on which actuators share the supply.
• First checks: Verify related fuses/relays, scan for companion DTCs, inspect harness routing for rub-through, and check for low system voltage/charging concerns.
• Common mistakes: Replacing an actuator before proving the supply circuit can carry load without voltage drop, or testing only with no-load voltage and missing a drop under operation.

Theory of Operation

Many powertrain actuators are powered by a shared supply circuit that originates at a fused feed, may pass through a relay, and is distributed through splices to multiple loads. The control module may not directly “create” this voltage; instead, it monitors the supply level (sometimes through an internal sense circuit) to ensure sufficient power is available when actuators are commanded. If the supply voltage is pulled down, actuators may respond slowly, erratically, or not at all.

A “circuit low” determination typically occurs when the module sees the monitored supply below its expected level for the current operating state. This can happen due to a short-to-ground, an open or high resistance on the power feed side, poor terminal contact, corrosion, or an actuator that draws excessive current and drags the supply down. Because this is load-sensitive, testing under commanded operation and with voltage-drop methods is often necessary.

Symptoms

• Warning lamp: Check engine light illuminated and P2674 stored.
• Reduced power: Limited acceleration or torque management if affected actuators are critical to control.
• Rough operation: Hesitation, unstable idle, or intermittent misbehavior depending on which actuators share the supply.
• No-start: Engine may crank but not start if the supply powers key control actuators.
• Stalling: Unexpected stall or near-stall when the circuit voltage drops under load.
• Intermittent faults: Symptoms that appear over bumps, during vibration, or when harness position changes.
• Additional DTCs: Other actuator or power-supply-related codes may be present due to a shared feed issue.

Common Causes

• Short-to-ground on the actuator supply voltage “D” feed circuit (chafed insulation, pinched harness)
• High resistance in the supply feed (corroded splice, partially broken conductor, overheated wiring) causing excessive voltage drop
• Poor connector contact at the actuator, junction, or control module (backed-out terminal, spread pins, moisture intrusion)
• Open or weak power source feeding the “D” supply (blown fuse, failing relay contacts, poor power distribution connection)
• Ground-side issue affecting the actuator’s ability to draw current correctly (loose ground point, corrosion at ground eyelet) leading to a low reading under load
• Internal fault in the actuator connected to supply “D” (electrical short or abnormal current draw pulling the supply low)
• Shared supply circuit problem (another component on the same supply “D” branch shorting or loading the circuit)
• Control module supply/driver sensing issue for the “D” circuit (less common; confirm wiring and loads first)

Diagnosis Steps

Tools typically needed include a scan tool capable of viewing live data and freeze-frame, a digital multimeter, and a wiring diagram/service information to identify which actuator(s) are on supply “D.” A test light may help for quick power checks, and back-probing tools are useful to avoid terminal damage. If available, use a breakout lead or fused jumper for controlled load testing.

1. Confirm the code and capture data: Scan for P2674 and any companion powertrain codes. Record freeze-frame data and note when it sets (key on, idle, under load). Clear codes and see if P2674 resets immediately or requires specific conditions.
2. Identify what “Actuator Supply Voltage D” feeds: Using service information (varies by vehicle), locate the actuator(s) and the exact circuit labeled supply “D,” including related fuses/relays, splices, and ground points.
3. Quick visual inspection: Inspect the harness routing to the actuator(s) and along the engine/transmission for chafing, contact with sharp edges, heat damage, or recent repairs. Pay close attention to areas where the harness flexes or is clipped tightly.
4. Connector and terminal checks: With ignition off, disconnect the actuator and relevant intermediate connectors. Inspect for corrosion, moisture, bent pins, poor pin tension, or pushed-back terminals. Correct any pin-fit problems before deeper testing.
5. Check the supply “D” fuse/relay path: Verify the feed protection and switching elements that provide power to supply “D.” If a fuse is open, do not replace it repeatedly—treat it as evidence of a possible short-to-ground or overcurrent load and continue testing.
6. Key-on power verification at the actuator connector: With ignition on (conditions per service info), measure the supply “D” voltage at the actuator connector and compare it to the specified reference point in service information. If it is low or missing, move upstream toward the power source to find where it drops.
7. Voltage-drop test under load: Command the actuator on with a scan tool (if supported) or enable the conditions where it normally operates, then perform voltage-drop testing across the supply “D” feed and the ground return path. Excessive drop indicates high resistance in wiring, connectors, splices, fuse/relay contacts, or ground points.
8. Short-to-ground isolation: If supply “D” is low and a short is suspected, disconnect loads on the supply “D” branch one at a time (actuator(s) and any shared components). Monitor whether the supply recovers when a particular load is unplugged. Use continuity/ohms testing to ground with the circuit de-energized to help pinpoint the segment that is shorted.
9. Actuator load check: If wiring and power feed test good, evaluate the actuator for abnormal current draw or internal short (method varies by vehicle). A component that draws excessive current can pull the supply low and trigger a circuit-low fault even when the feed is intact.
10. Wiggle test and live logging: With the scan tool logging supply-related PIDs (where available) and the engine running or key on, gently wiggle the harness, connectors, and junctions along the supply “D” path. If the value drops out or the code sets during movement, focus on that section for intermittent opens/high resistance or intermittent shorting.
11. Control module circuit confirmation: Only after confirming power/ground integrity, connector health, and actuator load, verify module-side power and ground feeds related to the sensing of supply “D.” If all external causes are eliminated, follow service information for module circuit tests and any required verification procedures.

Professional tip: When P2674 is intermittent, prioritize voltage-drop testing and live-data logging over static resistance checks. Many feed/ground problems only appear when the circuit is loaded (actuator commanded on) or when heat/vibration changes a weak connection. Document the exact operating condition that reproduces the low reading so you can retest after repairs and confirm the fix.

Possible Fixes & Repair Costs

Repair costs for P2674 vary widely because the underlying issue can be anything from a simple connector concern to deeper harness or control-module power/ground problems. Labor time also depends on actuator access and how the supply voltage “D” circuit is routed on your vehicle.

• Repair wiring faults: Locate and repair shorts-to-ground, rubbed-through insulation, pinched sections, or damaged splices in the actuator supply voltage “D” feed.
• Restore clean connector contact: Clean and secure terminals, correct poor pin fit, reseat connectors, and address corrosion or moisture intrusion found during inspection.
• Fix power distribution issues: Repair the affected fused feed, relay output, junction, or shared supply branch that is pulling the “D” circuit low.
• Repair ground problems causing voltage drop: Service the related ground points and return paths if testing shows excessive voltage drop under load.
• Replace the affected actuator: Only after confirming the actuator internally loads the supply circuit low (for example, abnormal current draw or internal short).
• Repair/replace harness section: If multiple repairs would be unreliable or the harness is compromised, replace the affected segment per service information.
• Control module service: If verified by testing and service procedures, repair programming/configuration issues or replace a module with a confirmed internal driver/supply fault.

Can I Still Drive With P2674?

Sometimes the vehicle may still drive with P2674, but it depends on which actuator uses the supply voltage “D” circuit and how the control system responds when that supply is low. If you have reduced power, stalling, a no-start, or any warnings related to braking or steering assist, do not continue driving; have the vehicle towed. If drivability seems normal, drive cautiously and only as needed while scheduling diagnosis, because the condition can worsen or become intermittent without warning.

What Happens If You Ignore P2674?

Ignoring P2674 can lead to recurring warning lights and progressive drivability issues if the low-voltage condition affects an important actuator. A persistent circuit-low fault may also cause secondary DTCs, disable certain control functions, or trigger a fail-safe strategy. If the root cause is wiring damage or a short-to-ground, continued operation can increase the risk of further harness damage and harder-to-diagnose intermittent faults.

Related Actuator Supply Codes

Compare nearby actuator supply trouble codes with similar definitions, fault patterns, and diagnostic paths.

• P2686 – Actuator Supply Voltage "G" Circuit Low
• P2682 – Actuator Supply Voltage "F" Circuit Low
• P2678 – Actuator Supply Voltage "E" Circuit Low
• P2690 – Actuator Supply Voltage "H" Circuit Low
• P0658 – Actuator Supply Voltage “A” Circuit Low
• P2684 – Actuator Supply Voltage "F" Circuit Range/Performance

Key Takeaways

• P2674 indicates a circuit-low condition on the actuator supply voltage “D” circuit, meaning the module detected the supply lower than expected.
• Most root causes are electrical: shorts-to-ground, high resistance, poor connections, or supply/ground distribution issues.
• Confirm with testing: verify the feed, ground integrity, and voltage drop under load before replacing parts.
• Impact varies by vehicle: symptoms and urgency depend on which actuator is powered by the “D” supply and what functions are affected.
• Fix the verified cause only: replacing an actuator without proving it loads the circuit low is a common, costly misstep.

Vehicles Commonly Affected by P2674

• Vehicles with multiple shared actuator supply feeds where one branch is labeled or mapped as supply voltage “D” in service information
• Vehicles using electronically controlled powertrain actuators that rely on dedicated power feeds monitored by the control module
• Applications with complex engine-bay wiring routed near heat sources or sharp edges that can chafe insulation
• Vehicles exposed to moisture or road debris where connectors and harness junctions are prone to corrosion or contamination
• High-mileage vehicles with aging terminals, weakened pin tension, or prior harness repairs
• Vehicles with recent powertrain service where connectors may be left partially seated or harness routing/clips disturbed
• Platforms with tight packaging that increases the chance of pinched wires near brackets or covers
• Vehicles with added electrical loads or modifications that can stress shared power/ground distribution if not integrated correctly

FAQ

What does “Actuator Supply Voltage ‘D’ Circuit Low” actually mean?

It means the powertrain control module detected that the monitored supply feed identified as actuator supply voltage “D” is lower than expected. This is a circuit-low electrical condition, typically caused by a short-to-ground, excessive resistance, or a weak/failed supply path rather than a mechanical problem.

Does P2674 tell me which actuator is failing?

No. P2674 identifies a low-voltage condition on the supply circuit labeled “D,” but which actuator(s) it powers varies by vehicle design. Use the appropriate service information and wiring diagrams to see what components share that feed, then test the circuit to isolate the load or wiring fault.

Can a bad connection cause P2674 without a failed part?

Yes. Poor terminal contact, corrosion, loose connectors, or damaged wiring can create enough resistance to pull the supply voltage down under load, triggering a circuit-low fault. This is why voltage-drop testing and connector inspection are essential before replacing any actuator.

Will clearing the code fix P2674?

Clearing the code only removes the stored fault record; it does not correct the underlying circuit-low condition. If the problem is still present, the monitor will typically fail again and the code will return, sometimes immediately under similar operating conditions.

What tests are most important for diagnosing P2674 correctly?

The most important tests are verifying the supply feed and ground integrity for the actuator supply voltage “D” circuit, performing voltage-drop testing under load, and isolating whether the harness/connection or a connected actuator is pulling the circuit low. Logging scan-tool data while wiggling the harness can help catch intermittent drops that a static check may miss.

Consult the vehicle’s service information to identify the actuator supply voltage “D” circuit routing and connected components before testing or repairs.