P1375 — Insufficient RMP Increase During Spark Test

What is the most common cause of P1375?

The most common causes are: open or shorted wiring in the circuit, control module driver fault, corroded, loose or damaged connector.

How much does it cost to fix P1375?

Control module repair — $300–$1,000; Replace the faulty sensor or actuator — $150–$500; Repair wiring or connectors — $80–$250. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

Is it safe to drive with P1375?

In most cases the car remains drivable, possibly with reduced performance or a disabled auxiliary system. If symptoms include stalling, no-start or brake/steering warnings, treat it as urgent.

Will P1375 clear itself?

Sometimes P1375 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

How do I diagnose P1375 myself?

Start with a scan: confirm P1375, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the sensor and actuator circuits, and verify the suspect component against live data before buying parts.

P1375 signals that the engine control module detected an insufficient RPM increase during a spark test sequence. When the ECM commands ignition under specific test conditions, it expects a predictable rise in engine speed. If that response doesn't happen, the module logs this trouble code. This isn't a one-time glitch detection—the computer must observe the fault repeat under defined operating conditions before it activates the check engine light and stores P1375 in permanent memory.

The code falls within the powertrain family of OBD2 diagnostics, meaning it concerns engine and transmission management systems. Every time P1375 triggers, the ECM captures a freeze frame snapshot: engine load percentage, RPM, coolant temperature, vehicle speed, and other sensor readings at the exact moment the fault occurred. That data proves invaluable during diagnosis because it lets you recreate the precise conditions under which the problem surfaced.

How the system works is straightforward. During a spark test, the ECM energizes the ignition circuit and monitors crankshaft acceleration. If the RPM response falls outside expected parameters, the module identifies a fault in the sensor or actuator circuit responsible for proper ignition timing and engine speed regulation. The underlying cause could be electrical, mechanical, or both—but the code specifically flags the symptom rather than naming a single culprit.

Common Symptoms of P1375

The check engine light illuminates and stays on until the fault clears. Depending on which specific circuit is affected, the vehicle may enter limp mode with severely restricted power output. The problematic system—whether ignition, fuel injection, or a related actuator—operates intermittently or stops functioning altogether. Some drivers report noticeably higher fuel consumption when this code is active. In mild cases, the car feels nearly normal aside from the persistent warning light. In more severe scenarios, acceleration feels sluggish or the engine stumbles under load.

What Causes P1375?

Loose, corroded, or physically damaged connectors rank among the most frequent culprits. A simple unplugged sensor or water-damaged terminal can interrupt the signal the ECM relies on. Blown fuses that feed power to the affected circuit also trigger this code. A faulty sensor or actuator within the ignition or engine management system fails to respond correctly to ECM commands. Open circuits—broken wires that interrupt current flow—create the same detection pattern. Shorted wiring, where a live wire contacts ground or another circuit, confuses the module's measurements. Finally, poor ground connections prevent components from completing their electrical circuits reliably.

How to Diagnose P1375

Begin by connecting an OBD2 scanner and confirming P1375 is stored in the ECM memory. Save the freeze frame data immediately—this snapshot tells you exactly what engine conditions existed when the fault was detected, including RPM, load, temperature, and speed. Never skip this step. Next, check for any related diagnostic trouble codes present at the same time. Accompanying codes often point directly to the root cause rather than the symptom. Also search for manufacturer technical service bulletins specific to your vehicle—many recurring OBD2 issues have documented factory fixes or software calibration updates available through the manufacturer website or NHTSA database. After reviewing service bulletins, perform a hands-on inspection of all wiring and connectors tied to the spark test circuit. Look for damaged insulation, corrosion buildup, bent pins, and loose plugs. Then measure reference voltage, ground integrity, and signal continuity at the component itself using a multimeter. The wiggle test—gently moving the harness while monitoring live data on your scanner—reveals intermittent dropouts caused by broken wires that only fail under vibration or movement. Finally, clear the code, complete a full drive cycle matching the freeze frame conditions, and verify P1375 does not return.

Repair Options for P1375

Tackle the cheapest and most common problems before replacing expensive components. Wiring harness repair or connector replacement typically runs $80–$250 depending on the extent of damage and labor involved. If a faulty sensor or actuator is confirmed, replacement generally costs $150–$500 for parts and installation. Control module diagnosis and repair, when necessary, ranges from $300–$1,000 depending on whether the ECM requires reprogramming, repair, or full replacement.

Total Repair Cost for P1375

The final bill hinges entirely on which component actually failed. Based on typical scenarios at independent repair shops in the United States, expect to pay between $80 and $250 for wiring or connector work, $150–$500 for sensor or actuator replacement, or $300–$1,000 if the control module itself is at fault. Most P1375 repairs fall somewhere in the $80–$500 range. Spending time on accurate diagnosis before purchasing parts always saves money—the control module scenario is rarely the first thing to check, yet it represents the highest cost if incorrectly assumed.

Can You Drive with P1375?

P1375 carries a short-term severity rating. In most instances, the vehicle remains drivable, though you may notice reduced performance or a disabled auxiliary system. The engine continues running, but not at full capability. Treat this as urgent only if the car exhibits stalling, failure to restart, or dashboard warnings related to braking or steering systems. Otherwise, schedule diagnosis and repair within a reasonable timeframe rather than driving indefinitely with an active fault.

Related OBD2 Codes

• P1300: Multi-faults - Bank 1 - With Low Side Shorts
• P1301: Multi-faults - Bank 2 - With Low Side Shorts
• P1302: Injector High Sides Shorted Together
• P1303: IDM Failure
• P1304: Cylinder Head Overtemperature Protection Active
• P1305: Boost Calibration Fault