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P0335 Crankshaft Position Sensor 'A' Fault Diagnosis - 2001 Pontiac Montana

Model: 2001 Pontiac Montana Fault Code: P0335 Posted: 2012-12-04 11:08

I recently replaced the crankshaft position sensor (sensor 'A') located behind the crank pulley and balanced shaft on my 2001 Pontiac Montana. After clearing the fault code using an OBD-II scanner, I drove the vehicle normally, but the check engine light returned and the P0335 code reappeared. My local auto parts store offers two types of crankshaft sensors for this model year—sensor 'A' and sensor 'B'. I'm wondering if the designation 'A' means that only one crank sensor exists on this vehicle, or could there be a second sensor (such as sensor 'B') contributing to the P0335 code. Since I don't have extensive automotive experience, I haven't performed any electrical diagnostics yet. Any guidance on troubleshooting this issue would be greatly appreciated.

Related fault codes

P0335

Comments (8)

Anonymous 2012-12-05 05:31

Hi! Thanks for sharing this post—it's helpful to see real-world experiences with common issues like P0335.

Anonymous 2012-12-05 08:38

You don't have an OBD-II scanner, so we're essentially guessing—could it be the sensor itself? The 7x sensor is located in the lower engine block, while the 24x sensor sits behind the harmonic balancer. Without knowing the exact code (P0335) or the conditions that triggered it, this remains speculative. Possible causes include wiring issues or a crankshaft relearn failure. Unfortunately, without proper diagnostic tools, this is just an educated guess.

Anonymous 2012-12-05 14:49

The code in question is P0335—Crankshaft Position Sensor 'A'. This confirms the issue is specifically related to sensor A.

Anonymous 2012-12-05 17:01

Yes, that makes sense. Using a scanner allows access to freeze frame data, showing exactly what conditions caused the code (e.g., engine RPM, temperature, crank position). Without this data, diagnosing is limited—your best bet right now is assuming it's a sensor failure. I appreciate your clarification on not having a scanner; it helps explain why troubleshooting is challenging for beginners. Still, knowing the exact symptoms and stored data would be key to accurate diagnosis.

Anonymous 2012-12-05 17:37

Got it—thank you for clarifying! I'm fairly new to car maintenance and learning as I go. Are there any affordable or free places where I can get a scan done?

Anonymous 2012-12-05 19:36

Yes, many auto parts chains like AutoZone offer free OBD-II code scans at their locations—just show up with your vehicle and they’ll help you read the codes.

Anonymous 2012-12-06 08:47

There's some confusion around what 'scan' means. A true diagnostic scanner (which costs $$$$) allows technicians to access the PCM’s memory, both live and stored data, and perform bidirectional commands—such as turning on/off emissions valves or engine fans. Simply knowing a code like P0335 isn’t enough to confirm sensor failure; it could point to wiring issues, insulation damage, or even a relearn problem. A good scanner helps avoid the misconception that every code means a sensor needs replacement. Experienced technicians use such tools combined with known common issues and simple tests to identify root causes—often without needing full diagnostics. This is especially important for GM vehicles where harnesses can degrade over time.

Anonymous 2012-12-16 11:24

On many GM engines, the wiring harness connecting the crankshaft position sensor gets exposed to power steering fluid, which can cause insulation to break down and lead to short circuits—this is a common failure point in older vehicles like the 2001 Pontiac Montana.