# 2018 Toyota 86: Engine Cranks But Won't Start (Crankshaft Position Sensor)

> ClearTheCode — Is your 2018 Toyota 86 engine cranking but won't start? A faulty crankshaft position sensor is a common culprit. Learn to diagnose and fix this issue quickly.

Source: https://clearthecode.com/articles/engine-crankshaft-position-sensor-failure-toyota-86-2018
Code: P0335
Author: ClearTheCode

# Engine cranks but won't start due to crankshaft position sensor 2018 Toyota 86

Few things are as frustrating as turning the key in your 2018 Toyota 86, hearing the engine crank vigorously, but having it stubbornly refuse to fire up. When your engine cranks but won't start, the crankshaft position sensor (CKP) is often the primary suspect. This critical sensor tells your car's engine control unit (ECU) the exact position and rotational speed of the crankshaft, which is essential for precise fuel injection and ignition timing. Without accurate data from the CKP, the ECU can't properly synchronize these processes, leading to a no-start condition.

## What drivers notice on this 2018 Toyota 86

When the crankshaft position sensor fails on a 2018 Toyota 86, the most immediate and noticeable symptom is the inability for the engine to start. You'll hear the starter motor engage and turn the engine over, creating the familiar cranking sound, but the engine will never "catch" or ignite. It's a distinct feeling of the engine trying, but failing, to come to life. There's no sputtering, backfiring, or rough idle; just continuous cranking without ignition.

## At a glance: difficulty, repair cost, and diagnostic workflow

- **Difficulty Rating:** 6/10 — 6/10 — Intermediate diagnostics
- **Common Symptoms:** Engine cranks but does not start: This is the hallmark symptom, where the starter motor works, but the engine never igni; Intermittent starting problems: The car might start sometimes, especially when cold, but then fail to start at other tim; Sudden stalling while driving: Though less common for a full no-start scenario, a failing CKP sensor can cause the engin; Rough idle or misfires: If the sensor provides inconsistent data, the ECU might struggle with timing, leading to an unst
- **Estimated Repair Cost:** $120–$450 (parts + typical shop labor)
- **OEM Tooling Required:** Standard OBD-II scanner and hand tools

**Diagnostic workflow:**
1. Confirm P0335 with a live scan — note pending vs stored and freeze frame data.
2. Inspect wiring/connectors and related sensors before replacing modules.
3. Clear codes and road-test; re-scan after two drive cycles if the monitor must set.

See the [P0335 code reference](/codes/P0335) and [topic hub](/hubs/fuel-trim-air-metering) for related guides.

## Symptoms and warning signs

While a complete no-start is the most common manifestation of a failed crankshaft position sensor, other symptoms might precede it or appear if the sensor is failing intermittently:

-   **Engine cranks but does not start:** This is the hallmark symptom, where the starter motor works, but the engine never ignites.
-   **Intermittent starting problems:** The car might start sometimes, especially when cold, but then fail to start at other times, particularly after the engine has warmed up.
-   **Sudden stalling while driving:** Though less common for a full no-start scenario, a failing CKP sensor can cause the engine to abruptly shut off while driving, often without warning.
-   **Rough idle or misfires:** If the sensor provides inconsistent data, the ECU might struggle with timing, leading to an unstable idle or engine misfires.
-   **Reduced engine performance:** Hesitation, lack of power, or poor acceleration can occur if the ECU is receiving incorrect RPM data.
-   **Check Engine Light (CEL) illuminated:** The ECU will almost certainly detect a fault with the CKP sensor and illuminate the CEL. A related diagnostic trouble code, P0335, specifically points to a [Crankshaft Position Sensor "A" Circuit Malfunction](/codes/P0335).

## How to verify and confirm the issue

Diagnosing a crankshaft position sensor issue on your 2018 Toyota 86 involves a few practical checks and potentially using an OBD-II scanner:

-   **Listen for fuel pump prime:** When you turn the key to the ON position (before cranking), listen for a brief hum from the rear of the car. This indicates the fuel pump is priming. If you hear it, fuel delivery might be okay, but still check for pressure.
-   **Check for spark:** Remove a spark plug, reconnect its coil, and ground the plug against a metal part of the engine. Have someone crank the engine briefly. If there's no spark, it strongly suggests a timing issue, often due to a faulty CKP sensor.
-   **Check for fuel injector pulse:** While more advanced, a mechanic can use a noid light to check if the fuel injectors are receiving a pulse signal from the ECU during cranking. No pulse, combined with no spark, points to a lack of engine synchronization.
-   **Use an OBD-II scanner:** Connect a scanner to your vehicle's diagnostic port. Look for stored or pending codes, especially P0335. Beyond codes, check live data during cranking. If the RPM reading shows 0 or erratic values while the engine is clearly cranking, the CKP sensor is likely faulty or its signal is not reaching the ECU.
-   **Visual inspection:** Carefully inspect the CKP sensor's wiring harness and connector for any signs of damage, fraying, corrosion, or loose connections. Sometimes, rodent damage or simply old, brittle wiring can be the culprit.

## Common causes (most likely first)

Several factors can lead to a crankshaft position sensor failure in your 2018 Toyota 86:

-   **Internal sensor failure:** Over time, the electronic components or magnetic pick-up inside the sensor can simply wear out or fail due to heat cycles and vibration.
-   **Damaged wiring or connector:** The wiring harness leading to the CKP sensor can become brittle, chafed, or corroded, interrupting the signal. The connector itself can also become loose or corroded.
-   **Debris on the sensor tip:** Metal shavings or other debris can accumulate on the magnetic tip of the sensor, interfering with its ability to accurately read the reluctor wheel.
-   **Reluctor wheel damage:** Though less common, the reluctor wheel (sometimes called a tone ring) on the crankshaft, which the sensor reads, can become damaged, bent, or have missing teeth, leading to incorrect readings.
-   **ECU issues:** In rare cases, the engine control unit itself might be failing to process the sensor's signal, or its internal circuitry related to the sensor input is faulty.

### Related guides on this vehicle

- [Engine Cranks But Won't Start No Fuel Pressure 2018 Toyota Rav4](/articles/engine-cranks-wont-start-no-fuel-pressure-toyota-rav4-2018)
- [Starter Solenoid Clicking But Engine Won't Crank 2020 Toyota Corolla](/articles/starter-solenoid-clicking-no-crank-toyota-corolla-2020)
- [1997 Toyota Avalon Won't Start After Sitting for Days](/articles/car-wont-start-after-sitting-3900-toyota-avalon-1997)

## Step-by-step diagnosis and fixes

Addressing a crankshaft position sensor issue on your 2018 Toyota 86 typically follows these steps:

-   **Safety first:** Always disconnect the negative terminal of your battery before working on electrical components.
-   **Locate the sensor:** On the Toyota 86 (and its Subaru BRZ twin), the crankshaft position sensor is usually located on the front of the engine block, near the crankshaft pulley, or sometimes closer to the transmission bell housing, reading off the flywheel. Consult a service manual for its exact location.
-   **Inspect wiring and connector:** Visually check the sensor's pigtail and the main harness connector for any signs of damage, corrosion, or looseness. Clean any corrosion with electrical contact cleaner.
-   **Test sensor resistance (if applicable):** Some CKP sensors can be tested for resistance with a multimeter, though many modern sensors require an oscilloscope to verify signal output. Refer to your vehicle's service manual for specific resistance values.
-   **Check for signal with an oscilloscope:** This is the most definitive test. An oscilloscope can display the waveform generated by the sensor during cranking. A missing, erratic, or incorrect waveform confirms a sensor or circuit issue.
-   **Replace the sensor:** If tests confirm the sensor is faulty, carefully remove the old sensor (usually held by one or two bolts) and install a new OEM-quality replacement. Ensure the O-ring or gasket is properly seated.
-   **Clear codes and retest:** After replacement, clear any stored diagnostic trouble codes using an OBD-II scanner. Attempt to start the vehicle. If it starts, allow it to run for a few minutes and recheck for any pending codes.

## Repair options and cost factors

Repairing a faulty crankshaft position sensor on your 2018 Toyota 86 generally involves replacing the sensor itself. The cost factors include:

-   **Parts cost:** A new OEM or high-quality aftermarket crankshaft position sensor for a Toyota 86 typically ranges from $50 to $150. Be wary of extremely cheap sensors, as quality can vary significantly.
-   **Labor cost (if professional):** If you take your car to a professional mechanic, expect labor costs to range from $100 to $300, depending on the shop's rates and the sensor's accessibility. The job itself is not overly complex for an experienced technician.
-   **Diagnostic fees:** Many shops charge a diagnostic fee (often around $80-$150) to accurately identify the problem, which may be waived if they perform the repair.

DIY replacement can save on labor costs, provided you have the necessary tools and confidence. For a broader understanding of common automotive issues, you can explore our repair guides.

## When to see a professional

While replacing a crankshaft position sensor can be a DIY task for some, there are times when seeking professional help is the best course of action:

-   **Uncertain diagnosis:** If you've performed basic checks and are still unsure if the CKP sensor is the root cause, a professional can use advanced diagnostic tools like an oscilloscope to confirm.
-   **Lack of specialized tools:** If you don't have an OBD-II scanner, multimeter, or an oscilloscope, accurate diagnosis can be challenging.
-   **Difficulty accessing the sensor:** Some sensors are in tight spots, requiring specific tools or knowledge for removal and installation.
-   **Suspected deeper issues:** If the problem persists after sensor replacement, or if you suspect related issues like a damaged reluctor wheel or ECU fault, a professional can investigate further. If you're curious about other vehicle-specific information, browse our [vehicles database](/vehicles).

## Frequently asked questions

### Can a bad crankshaft position sensor cause a car to stall while driving?
Yes, absolutely. If the crankshaft position sensor fails intermittently while the engine is running, the ECU will lose crucial timing information, causing the engine to immediately shut down or stall. This can be a dangerous situation, especially at highway speeds, as power steering and power brakes may also be affected.

### How long does a crankshaft position sensor last on a 2018 Toyota 86?
The lifespan of a crankshaft position sensor can vary significantly, but they are generally designed to last the life of the vehicle. However, like any electronic component exposed to heat and vibration, they can fail prematurely. It's not uncommon for them to last well over 100,000 miles, but some may fail earlier due to manufacturing defects or environmental factors.

### Is it hard to replace the crankshaft position sensor on a Toyota 86?
Replacing the crankshaft position sensor on a Toyota 86 is generally considered a moderately difficult DIY task. The primary challenge often lies in accessing the sensor, which can be in a tight spot depending on the engine design. With the right tools, a service manual for exact location, and some patience, it's a manageable repair for someone with basic mechanical experience.

## Sources and further reading

This information is provided for educational purposes and is not a substitute for OEM service procedures. Always consult your vehicle's factory repair manual and use a qualified technician for safety-critical work.

## Explore related guides on ClearTheCode

- [Browse OBD-II codes](/codes)
- All repair guides