If you're searching 'how many camshaft position sensors are there,' the short answer is: most modern engines have at least one, and many have two. On a BMW E46, it's two—one for the intake camshaft and one for the exhaust camshaft. But the count is not the expensive part. The expensive part is what happens when you order a replacement without checking the actual specifications.
I'm a procurement manager at a 24-person automotive parts and repair operation. I've managed our spare parts budget ($210,000 annually) for six years, negotiated with 40+ vendors, and tracked every order in a cost system that catches mistakes. This is the advice I'd give to a shop owner or fleet buyer before they hit 'buy.'
Why the Sensor Count Is Easier Than the Sensor Identification
The sensor count depends on engine design. A single-overhead-cam inline engine might have one. A dual-overhead-cam inline engine often has two—one per camshaft. A V6 or V8 can have two or more, depending on whether the ECU needs to see each camshaft independently. That's why you can't rely on a universal 'how many' answer.
For the E46, the answer is two. The intake camshaft position sensor and the exhaust camshaft position sensor are usually sold separately. They look similar, but the connectors and resistance values are not always interchangeable. I've watched a shop save $12 by buying the 'compatible' one and then spend two hours trying to figure out why the car wouldn't start. (Note to self: always confirm the part number before installation.)
It's tempting to think that all camshaft sensors with the same connector are the same. They're not. The signal output, the sensor gap, and the housing dimensions all matter. 'Fits the connector' is not the same as 'matches the engine's requirements.'
What a Part Number Actually Buys You
Take the Valeo 28-beam titanium wiper blade 604488. The number tells you it's a 28-inch beam blade, but it doesn't tell you whether the adapter fits your wiper arm. Valeo support lists the 604488 as a specific length and blade type, and the catalog shows the connector range. If you ignore the connector and buy based on a vehicle filter alone, you might end up with a blade that is too long or attaches to nothing. The part number is not a SKU. It's a specification lock.
Why does this matter? Because a wrong part is never just the cost of the part. It's the return shipping, the time you spent ordering, the technician's time, and the delay. That's the total cost of ownership, not the sticker price.
When I Ignored the GM Transmission Mount Dimensions
I only started checking GM transmission mount dimensions after I ignored a lead tech's warning and ordered a mount based on 'it fits your transmission.' The part fit the transmission. It did not fit the car. The mounting holes on the crossmember were off by about 8 mm, and the overall height was too tall. We had already paid for a hoist and two hours of labor before the alignment issue showed up. That 'simple' $140 mount ended up costing us $420 including return shipping.
What I mean by dimensions is not just the bolt pattern. It's the overall height, the mounting hole spacing, the metal sleeve position, and the stud length. GM uses different mount patterns on similar transmission families. The same transmission name can appear in different vehicle platforms with different brackets. That's why a dimension sheet is worth more than a 'fits' table.
When Paying for Certainty Is the Right Call
In Q2 2024, we paid $36 extra for overnight delivery on an E46 camshaft position sensor. The car was booked for a Friday return. If we missed that deadline, we would have lost a $1,200 job and had to reschedule two other appointments. The $36 was not paying for speed. It was paying for a delivery date that the supplier committed to.
The 'probably on time' option from a lower-price vendor was $22 cheaper. Did I trust it? Not entirely. The vendor's tracking page said 'estimated,' and the phone number on the website went to voicemail. In an emergency, 'estimated' is a risk, not a plan.
Now the counterpoint: if the vehicle is sitting in your lot and nobody needs it until next week, you don't need rush delivery. The worst thing you can do is pay for urgency when you don't have a deadline. But if the deadline is real, the uncertain cheap option is usually the most expensive one.
What I Check Before Every Replacement Order
- The OEM part number and the aftermarket cross-reference. If the numbers don't line up, I keep looking.
- Physical dimensions. For mounts, I ask for a dimension sheet with bolt spacing and height. For sensors, I check connector shape and housing length.
- Sensor type. Hall effect and inductive sensors are not interchangeable, even if the connector fits.
- Support phone number. A brand that publishes support documentation and has a real phone line is worth a few extra dollars. Valeo support has saved me from at least two wrong orders.
Also, be careful with 'OEM-grade' claims. Per FTC advertising guidelines (ftc.gov), product claims have to be substantiated. If a listing says 'OEM quality' but the seller can't provide a spec sheet, I treat that as a red flag, not a guarantee.
The Boundary Conditions
This approach works for independent shops, small fleets, and repair buyers. If you're a Tier 1 purchasing agent ordering production parts with PPAP documents, you already live in a different world. You'll have more paperwork, and the part dimensions will be locked down by the customer. For everyday replacement parts, checking specifications is the difference between a quick fix and a second repair.
Part numbers change. As of January 2025, the Valeo 604488 and the E46 sensor specs I've referenced here were still in the catalog. The market changes fast, so verify current part numbers and dimensions before you order. I don't have hard data on how many aftermarket 'fits' are wrong, but based on six years of tracking our own orders, I'd estimate that 5–10% of them need a closer look.
So, how many camshaft position sensors are there? It depends on the engine. For the E46, it's two. For many modern engines, it's two. But the real question is whether the one you're buying is the right one for that specific position. The count is easy. The confirmation is the job.
