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Common Symptoms of a Bad Crankshaft Position Sensor
Recognizing the signs of a faulty crankshaft position sensor can prevent further damage and costly repairs. Here are some common symptoms:
- Trouble starting the engine. If the sensor is not sending the correct signals, the ECU may not know when to trigger fuel injection and ignition, leading to difficulties starting the vehicle.
- Intermittent stalling. If your car stalls randomly while driving or at idle, it could be due to a faulty crankshaft position sensor.
- Check Engine Light is on. A malfunctioning sensor can trigger the Check Engine Light on your dashboard.
- Poor acceleration. If your vehicle doesn’t accelerate smoothly or as quickly as usual, the sensor might be to blame.
- Fuel efficiency concerns. A bad crank sensor can throw off the fuel injection timing, resulting in decreased gas mileage.
When the crankshaft position sensor is working erratically, these symptoms can come and go seemingly randomly. It can make it tricky to figure out what’s at the heart of the issue.
Diagnosing a Faulty Crankshaft Position Sensor
If your symptoms line up with a potential issue with the crank sensor, there are a handful of tests you can perform to either rule out or confirm it.
- Perform a scan test. With a Check Engine Light on, trouble codes will be stored in the onboard computer that can help identify whether the crank sensor is faulty. DTCs will often be directly related to the crank sensor, and they’re often accompanied by other codes related to misfires, timing, or injection.
- Monitor the sensor’s operation. Using your OBD-II scanner, run the engine and monitor the sensor’s readings and the engine’s RPM to see if the sensor is working correctly.
- Check the sensor’s resistance. You can use a multimeter to check the sensor’s resistance. You’ll need a helper to crank the engine over while you test. It should switch from zero to five volts rapidly.
Consequences of Ignoring a Bad Crankshaft Position Sensor
Ignoring a bad crankshaft position sensor can lead to a variety of serious consequences for your vehicle. Here are some potential outcomes if the problem is not addressed:
- Engine damage. The sensor’s role in managing ignition timing and fuel injection is crucial, and when these processes are disrupted, it can lead to inefficient combustion and stress on various engine parts.
- Poor performance. A car with a bad sensor might experience rough idling, prolonged cranking, or may not start at all. These issues obviously can make driving difficult and potentially unsafe.
- Decreased fuel efficiency. A bad sensor can disrupt the timing of your fuel injection, leading to decreased fuel efficiency and cause you to spend more on gas than you should be.
- Sudden stalling. A bad sensor can cause your engine to stall suddenly, which can be dangerous, especially if you’re driving at high speeds or in heavy traffic.
- Wear and tear. Ignoring the symptoms of a bad crankshaft position sensor can result in rapid wear and tear of various engine parts, leading to costly repairs down the road.
Troubleshooting Tips and Solutions
If you’re thinking the crankshaft position sensor might be bad, be sure before you replace it. Otherwise, your symptoms might still be present, and you’ll be out the time and money for your new sensor.
- Are all of the DTCs plausibly related to the crankshaft position sensor? Some codes might be present that can indicate some other issue that might be a more likely culprit for your symptoms.
- Is the sensor clean? Remove the sensor if it doesn’t require major disassembly. Check for dirt or oil on the sensor, clean it and re-install, and check if the problem has cleared up.
- Is the connector tight and clean inside? A corroded or loose connector could be to blame, ending up as a quick fix.
If all of your efforts still lead you to a bad crank sensor, install a new one, clear the codes, and check if the symptoms are resolved.
Seek Professional Help or DIY?
If your crankshaft position symptoms are intermittent or you’re unsure of your skills in diagnosing and replacing the sensor, a professional mechanic should be consulted. Done incorrectly, it can lead you into a big can of worms that gets more complicated.
However, if you’re a capable DIYer, diagnosing and replacing a crank sensor isn’t a major repair. Common tools are all it takes to get the job done right, along with a high-quality replacement part.
Looking for a new crankshaft position sensor? AutoZone can get one in your hands quickly, whether you shop online or in-store.
FAQ/People Also Ask
How do I know if my crankshaft position sensor is bad?
A bad crankshaft position sensor can lead to issues like stalling, misfires, or trouble starting the engine.
What happens when a crankshaft position sensor goes bad?
When a crankshaft position sensor goes bad, the engine may not start, run rough, stall, or experience poor performance.
What causes crank sensor failure?
Crank sensor failure can be caused by wiring problems, sensor damage, or issues with the reluctor wheel.
Can a crankshaft sensor cause engine failure?
A faulty crankshaft sensor can contribute to engine performance problems and stalling, but it’s not the sole cause of engine failure.
Can a car run without a crankshaft position sensor?
A car can run without a crankshaft position sensor, but it may not start or run properly, leading to poor performance and potential stalling.
