A few of the symptoms of a failing or faulty camshaft position sensor include rough idling, hard starting, stalling, lowered fuel economy (reduced MPG), poor acceleration, misfiring, loss of power, jerking, surging, a CEL / SES (check engine / service engine soon) warning light on the gauge cluster and possibly also backfiring.

If you have an OBDII Scanner (also known as an OBD2 scan tool), some of the camshaft position sensor related DTC (diagnostic trouble codes) you might see include the following: P0340, P0341, P0342, P0343, P0344, P0345, P0346, P0347, P0348 and P0349.

Owners of other Toyota, Lexus or Scion vehicles such as the Yaris, Matrix, Prius, Camry, RAV4, Sienna, Tacoma, Tundra, FJ Cruiser, Venza, Highlander, Avalon, Sequoia, Land Cruiser, Allion, Premio, Auris, IS 250, ES 350, GS 350, tC, xB, xD, iQ and FR-S may also find these DIY instructions to be helpful.

The OEM (original equipment manufacturer) sensor part number is Denso 196-1001 (also known as part # 1961001 or 9091905060).

A few other compatible replacement sensors with their part numbers include the following: Delphi SS10939, Beck Arnley 180-0499, Holstein Parts 2CAM0057, CCIYU 102745-5210-1421456061 and Walker Products 235-1343.

The tools needed to complete this procedure include a 10mm socket and a 1/4" drive ratchet.

The first two steps are to open the hood and then gently pull off the plastic engine cover. The cover is held in place by four rubber friction fasteners attached to metal pegs on the top of the engine. Set the cover aside in a safe place.

Then disconnect the "-" negative battery terminal by loosening the nut a few turns in the counterclockwise direction with the 10mm socket and a 1/4" drive ratchet.

Wrap the negative terminal in a small towel and tuck it away on the right side of the battery to help prevent accidental electrical contact.

They are both located on the right (driver) side of the valve cover close to the engine air filter housing.

The front unit is the intake camshaft sensor and the rear unit is the exhaust camshaft sensor.

For this guide, I'll be replacing the front sensor.

If you have access to compressed air or a wet/dry shop vacuum, clean off the top of the engine to reduce the risk of having sand or other debris fall down into the sensor port.

Carefully push in the release tab on the gray plastic electrical connector before pulling it straight off the old sensor.

Set the bolt aside in a safe place.

Gently rotate the old sensor back and forth or wiggle it to loosen the rubber o-ring gasket.

Carefully pull the sensor out of the top of the engine.

Try to avoid using excessive force to prevent from having the rubber o-ring gasket tear or the sensor itself break apart.

If the o-ring rips apart or the old sensor breaks, the pieces could fall down into the engine.

I would recommend either buying the OEM Denso 196-1001 sensor or the Beck Arnley 180-0499 sensor which has excellent reviews on Amazon.

Apply a small amount of new engine oil to the rubber o-ring gasket on the new sensor.

Lubricating the o-ring will make it easier to install the sensor, help it form a better seal and prevent oil leaks.

Lower the new sensor straight down into the port with the bolt holes lined up.

Tighten the bolt in the clockwise direction with the 10mm socket and a 1/4" drive ratchet until it is snug.

Avoid over tightening the bolt to prevent from cracking the plastic sensor housing.

If you need to replace a broken electrical connector, the OEM part number is Toyota 90980-12353 (or 9098012353).

You should feel or hear the connector "click" securely into place.

Carefully re-connect the negative terminal to the "-" battery post and tighten the terminal nut in the clockwise direction until it is snug. Try to avoid over tightening the terminal nut to prevent from cracking the battery post which could lead to an acid leak.

Start the engine and listen closely for any strange sounds. If you do hear any weird noises, immediately turn off the ignition and double check your work.

Check to see if the SES / CEL (service engine soon / check engine light) warning appears on the gauge cluster.

If the engine is running properly, push the plastic cover back into place.

Be sure to write down the sensor(s) change in your vehicle's service records.

Please check out my other Corolla DIY tutorials at the links below -

2009-2013 Toyota Corolla Repair & Maintenance Guides

2014-2018 Toyota Corolla Repair & Maintenance Guides

2003-2008 Toyota Corolla Repair & Maintenance Guides