A Guide to the Ignition Knock Sensor for the 2016 Scion iA
Understanding how this small sensor protects your iA's engine and when it's time for a replacement.
- The 2016 Scion iA is a rebadged Mazda 2; the knock sensor is a Mazda part (OEM # PE01-18-921).
- Replacement is labor-intensive (1.5-2.5 hours) because the sensor is located under the intake manifold.
- The most common symptom is a Check Engine Light with code P0327, along with poor acceleration.
- Due to the high labor cost, choosing a quality aftermarket brand like Standard Ignition or an OEM part is recommended over a budget option.
Understanding Your Scion iA's Engine
The 2016 Scion iA is unique because it's essentially a rebadged Mazda 2, using a Mazda 1.5L SKYACTIV-G engine. This is important because the knock sensor and many other parts are Mazda-designed. When searching for information or parts, knowing this connection can be very helpful. The original Mazda part number for this sensor is PE01-18-921.
Symptoms of a Failing Knock Sensor
When a knock sensor fails, the ECU can no longer hear if the engine is knocking. To be safe, it switches to a conservative "safe mode." This involves reducing engine power to prevent potential damage. You will likely notice one or more of the following symptoms:
- Check Engine Light: This is the most common symptom. The ECU will store a fault code, most often P0327 (Knock Sensor Circuit Low Input), P0325, or P0328.
- Poor Acceleration: The car will feel sluggish and slow to respond, especially when you're trying to get up to speed.
- Reduced Fuel Economy: The engine's safe mode is less efficient, so you'll notice you're getting worse gas mileage.
- Engine Pinging (Rarely): In some cases, you might hear a metallic pinging sound, but the ECU's safe mode usually prevents this.
Is It the Sensor or Something Else?
An audible engine knock can be a sign of serious mechanical problems, not just a bad sensor. Issues like low oil, old oil, or worn internal engine components can also cause knocking sounds. It's wise to have a proper diagnosis performed before assuming the sensor is the only problem.
Choosing the Right Aftermarket Knock Sensor
For your 2016 Scion iA, you have a choice between OEM (from a Toyota/Mazda dealer) and several aftermarket brands. Since this sensor is difficult to access, choosing a quality part is important to avoid paying for the same labor twice.
- Standard Ignition (SMP): Often considered a top-tier aftermarket brand, Standard Motor Products can be a reliable alternative to OEM. They are known for quality manufacturing.
- Beck Arnley: This brand focuses on sourcing parts that match the original vehicle's needs. In the past, they often re-boxed OEM parts, but quality can vary. It's a well-known name in import parts.
- Global Parts Distributors (GPD): This brand is typically positioned as a value or budget-friendly option. For a part with high labor costs for replacement, weigh the lower part cost against the risk of a shorter service life.
A Note on OEM vs. Aftermarket
For sensitive electronic sensors like a knock sensor, an OEM part guarantees a perfect fit and reliable performance. However, a high-quality aftermarket part from a reputable brand like Standard Ignition can offer comparable performance for less money. Given the labor involved in this specific replacement, a budget part is a riskier choice.
Replacement Cost for a 2016 Scion iA Knock Sensor
The knock sensor is located under the intake manifold on the iA's 1.5L engine. This makes replacement more labor-intensive than on many other vehicles. A professional mechanic will need to remove the manifold to access the sensor, which increases the labor time and cost.
| Part Type | Estimated Part Cost | Estimated Labor Cost |
|---|---|---|
| New Aftermarket | $31.78 - $57.59 | $150 - $250 |
| New OEM (Mazda) | $65 - $85 |
Frequently Asked Questions (FAQ)
Where is the knock sensor located on the 2016 Scion iA?
The knock sensor is bolted to the engine block, underneath the intake manifold. The manifold must be removed to get to it, making it a moderately difficult job.
What does the code P0327 mean?
P0327 stands for "Knock Sensor 1 Circuit Low Input." It means the engine's computer has detected that the voltage signal from the knock sensor is lower than it should be. This is often caused by a faulty sensor, a bad electrical connection, or damaged wiring.
Can I drive my Scion iA with a bad knock sensor?
You can drive for a short time, but it's not recommended for long. The engine will be in a low-power "safe mode," resulting in poor acceleration and bad fuel economy. Ignoring the problem could risk engine damage if a severe knock occurs that the computer cannot detect.
Are there any recalls for the 2016 Scion iA knock sensor?
No, there are no specific recalls or Technical Service Bulletins (TSBs) from Scion or Toyota for a faulty knock sensor on the 2016 iA.
Is the Scion iA knock sensor a Toyota part or a Mazda part?
It is a Mazda part. The 2016 Scion iA was built by Mazda and uses a Mazda engine and electronics. The OEM part number is a Mazda number, PE01-18-921.
Technical Specifications
OEM Part Numbers: PE01-18-921 SU003-06707
Single bolt-on piezoelectric sensor, typically with a 2-pin electrical connector, mounted to the engine block under the intake manifold.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Scion iA: