Obd2 Scanner for Diagnosing Crankshaft Position Sensor Clicking When Turning Left

There's a strange clicking noise coming from your engine every time you turn left, and you've narrowed it down to something around the crankshaft position sensor. Maybe a forum post pointed you in that direction, or maybe a mechanic mentioned it but you want to verify the diagnosis yourself before paying for a repair you might not need. That's exactly where an OBD2 scanner becomes useful it lets you pull diagnostic trouble codes and live data from your car's computer so you can confirm whether the crankshaft position sensor (CKP) is actually the problem behind that left-turn click.

Why would a crankshaft position sensor click when turning left?

This isn't as strange as it sounds. The crankshaft position sensor reads the rotation speed and position of the crankshaft and sends that data to the engine control module (ECCM). When you turn left, several things happen at once:

Vehicle weight shifts to the right side, which can put slight stress on engine mounts and components
Steering and suspension movement may tug on nearby wiring harnesses
Loose or corroded connectors around the sensor can momentarily lose contact
The sensor itself may have internal damage that only shows up under specific vibration patterns

That clicking sound is often a relay or the sensor cutting in and out. When the ECM loses the CKP signal even for a split second, it may trigger a relay click, a fuel injector misfire, or a brief ignition stumble that you hear as a click or tick.

Can an OBD2 scanner actually detect this kind of intermittent fault?

Yes, but with a catch. A basic OBD2 scanner will pull stored and pending trouble codes, which is a solid starting point. If the crankshaft position sensor has glitched enough times during left turns, the ECM has likely logged a code. Common related codes include:

P0335 Crankshaft Position Sensor "A" Circuit Malfunction
P0336 Crankshaft Position Sensor "A" Circuit Range/Performance
P0337 Crankshaft Position Sensor "A" Circuit Low Input
P0338 Crankshaft Position Sensor "A" Circuit High Input
P0339 Crankshaft Position Sensor "A" Circuit Intermittent

P0339 is the one you're most likely to see with an intermittent left-turn click, since it specifically flags an intermittent signal. If you see this code paired with complaints that match yours clicking on left turns, possible stalling, rough idle under specific conditions that's a strong signal the CKP sensor or its wiring is the issue.

A more advanced scanner with live data capability lets you watch the crankshaft position signal in real time. You can record data while someone else drives the car and makes a left turn. If the signal drops out or spikes during the turn, you've found your problem. For setting up that kind of real-time monitoring, a diagnostic oscilloscope can be helpful for capturing the exact moment the sensor signal drops during a left turn.

What if no codes show up on the scanner?

This happens more often than people expect with intermittent issues. If the glitch is too brief, the ECM might not log a code at all, or it might store only a pending code that clears after a few drive cycles. Here's what to do:

Check for pending codes not just confirmed codes. Many scanners default to showing confirmed codes only.
Look at freeze frame data if a code did log at some point, the freeze frame captures the engine conditions at that moment (RPM, speed, load, temperature).
Use live data streaming monitor the CKP sensor RPM signal while driving and reproducing the left turn. You're looking for drops to zero or erratic jumps.
Check for related codes sometimes a CKP problem triggers camshaft position sensor codes (P0340–P0349) or misfire codes (P0300–P0312) as a side effect.

If you're not sure how to pull and read these codes step by step, this walkthrough on using a code reader to isolate crankshaft sensor clicking sounds covers the hands-on process in detail.

Is it really the sensor, or could it be something else?

This is the question most people skip, and it costs them money. A clicking sound on left turns can also come from:

CV joint or axle issues these click loudly on turns and are much more common than CKP sensor problems
Loose heat shields or exhaust components they shift under turning forces and rattle against the chassis
Worn engine mounts the engine moves slightly during turns, causing contact with surrounding parts
Steering column or intermediate shaft clicking sounds like it's coming from the engine bay but isn't
Low power steering fluid (if hydraulic) can cause pump cavitation noise on full-lock turns

The OBD2 scanner helps here because if no CKP-related codes exist and live data looks normal, you can rule out the sensor and focus on mechanical causes instead. That's worth knowing before you spend $80–$200 on a sensor replacement that won't fix the noise.

What OBD2 scanner features do you actually need for this?

Not every scanner will give you what you need. Here's what matters for diagnosing a CKP sensor click:

Reads pending and confirmed codes essential for catching intermittent faults
Live data streaming so you can watch CKP sensor output in real time
Freeze frame data shows what the engine was doing when a code triggered
Recording or graphing function lets you capture data while driving and review it later
OBD2 compatibility with your vehicle most 1996+ vehicles work, but some older or European models need enhanced protocols

You don't need a $3,000 professional tool for this job. Mid-range scanners in the $80–$200 range from brands like BlueDriver, Innova, or Launch typically cover all the features above. If you're still deciding what tools to pick up, here's a breakdown of the diagnostic tools you'll need for this specific problem.

Common mistakes when using a scanner for this diagnosis

A few things trip people up:

Clearing codes too early if you erase the codes before reviewing freeze frame data, you lose valuable information about when and how the fault happened
Only reading confirmed codes pending codes are where intermittent CKP faults often hide
Ignoring wiring the scanner tells you the circuit has a problem, but it won't tell you if a wire is chafed against the engine block. You still need a visual inspection
Replacing the sensor without testing codes point to a circuit problem, which could be the sensor, the wiring, the connector, or even the ECM. Testing with a multimeter before swapping parts saves time and money
Not reproducing the exact conditions if the click happens on left turns, you need to scan while making left turns. Sitting in the driveway and reading codes might show nothing useful

Step-by-step: Using your OBD2 scanner to confirm the CKP sensor diagnosis

Connect the scanner to the OBD2 port (usually under the dashboard on the driver's side).
Read all codes confirmed, pending, and any stored in manufacturer-specific modules if your scanner supports it.
Check freeze frame data for any CKP-related codes. Note RPM, vehicle speed, and engine load.
Switch to live data mode and find the CKP sensor PID (often labeled "CKP RPM" or "Engine RPM").
Start recording or switch to graph mode.
Drive the vehicle and reproduce the left turn where the click happens. Have a passenger watch the scanner screen or review the recording afterward.
Look for signal dropouts the RPM reading should stay smooth and consistent. Spikes, flatlines, or gaps in the data during the turn point to a sensor or wiring fault.
Inspect the sensor and connector if the data confirms a fault. Check for corrosion, loose pins, damaged wiring, and physical damage to the sensor.
Test the sensor with a multimeter compare resistance readings to manufacturer specs. A typical CKP sensor reads between 200 and 1,000 ohms, but always check your vehicle's service manual for exact values.

When should you stop scanning and take it to a shop?

If you've pulled codes, reviewed live data, and inspected the wiring but still can't pinpoint the problem, it's time for professional help. An intermittent CKP signal that only shows up during left turns could involve internal wiring harness damage that's hard to access, or an ECM issue that requires dealer-level tools to diagnose. A shop with an oscilloscope and manufacturer-specific software can dig deeper than a handheld scanner can.

Also, if the clicking is accompanied by the engine stalling, losing power, or refusing to start intermittently, don't keep driving it hoping the scanner will give you a clear answer. A failing CKP sensor can leave you stranded. Get it looked at before it becomes a safety issue.

Quick checklist for diagnosing CKP sensor clicking on left turns with an OBD2 scanner

✅ Connect OBD2 scanner and read all code types (confirmed, pending, permanent)
✅ Look for P0335–P0340 codes, especially P0339 (intermittent circuit)
✅ Review freeze frame data for conditions when the code last triggered
✅ Monitor CKP sensor live data while reproducing the left turn
✅ Record or graph the signal to catch brief dropouts
✅ Physically inspect the CKP sensor, connector, and nearby wiring for damage
✅ Test sensor resistance with a multimeter against factory specs
✅ Rule out CV joints, engine mounts, and steering components if no CKP codes appear
✅ Don't clear codes until you've documented everything
✅ Consult a professional if the issue persists after sensor and wiring inspection

Tip: Before you replace the crankshaft position sensor, unplug its connector, spray it with electrical contact cleaner, and reseat it firmly. A corroded or loose connector is the cheapest and most overlooked fix for intermittent CKP signal problems. It takes five minutes and costs under $8 worth trying before spending more on parts.