On the 4th-generation CR-V the upstream sensor sits in the exhaust manifold on the firewall side of the K24, and it is one of those jobs that is either 30 minutes or a nightmare depending on how badly the sensor has rusted into its threads. Nothing is technically difficult: one connector, one threaded sensor, a 22 mm slotted socket. The whole battle is leverage in a tight space and penetrating oil.
The mistake people make most is buying a plain narrowband oxygen sensor instead of the wideband air/fuel ratio sensor the front position uses, or buying a universal splice-in unit. Either one gives you a fresh check engine light and poor fuel trims. Buy the correct A/F sensor with the factory connector, soak the threads before you pull, and torque it to spec rather than gorilla-tightening it into the manifold.
| Item | Type | |
|---|---|---|
| Wheel chocks Keeps the car from moving if you lift the front for access from below. | Safety | shop |
| Floor jack 2 ton minimum Lifts the front end if you choose to reach the sensor from underneath. | Recommended | shop |
| Jack stands 2 ton pair Supports the vehicle while you work under it. | Safety | shop |
| Mechanic's gloves Protects hands on hot, sharp exhaust and manifold shield edges. | Safety | shop |
| Penetrating oil PB Blaster or equivalent Soaks the seized sensor threads in the manifold before removal. | Consumables | shop |
| Socket set 10 mm and 12 mm sockets, 3/8 in drive Removes the engine/manifold heat shield bolts (10 mm) and any splash shield fasteners (10/12 mm). | Required | shop |
| Ratchet 3/8 in drive, long handle Drives the sockets and the O2 sensor socket. | Required | shop |
| Extensions 3/8 in drive, 6 in and 10-12 in Reaches the sensor down behind the engine or up from below. | Required | shop |
| Swivel/wobble adapter 3/8 in drive Lets the socket line up with the sensor in the tight firewall gap. | Recommended | shop |
| Oxygen sensor socket 22 mm slotted, 3/8 in drive Slotted socket passes the sensor wiring harness while gripping the hex. | Required | shop |
| Oxygen sensor wrench (alternative) 22 mm offset crowfoot or 7/8 in Useful if the socket will not fit the tight space around the sensor boss. | Recommended | shop |
| Breaker bar or pipe 3/8 or 1/2 in drive with adapter Extra leverage to break a heat-seized sensor loose. | Recommended | shop |
| Trim/panel pry tool Plastic Releases the harness clips and connector lock without breaking them. | Recommended | shop |
| Wire brush Brass or steel, small Cleans the manifold threads and boss face before installing the new sensor. | Consumables | shop |
| Torque wrench 3/8 in drive, 10-80 ft-lb range Sets the sensor to spec so it seals without stripping the manifold threads. | Required | shop |
| Anti-seize compound Nickel-based, O2 sensor safe Only if the new sensor threads are not pre-coated; keep it off the sensor tip. | Consumables | shop |
| OBD-II scan tool Code reader with live data Clears the stored P0135/P0137/P2195-type code and confirms the new sensor reads correctly. | Recommended | shop |
| Air/fuel ratio sensor Front/upstream A/F sensor for 2.4L (Denso/OEM Honda 36531-...) The replacement wideband sensor; must be the A/F sensor, not a plain O2 sensor. | Parts | shop |
All 2012-2016 CR-Vs in the US use the 2.4L K24 (K24Z6 for 2012-2014, K24W direct-injection Earth Dreams for 2015-2016), so socket sizes are identical: 22 mm sensor hex, 10 mm shields. The 2015-2016 Earth Dreams engine has a tighter manifold shroud and a different sensor part number, so a swivel extension helps and the part must be matched to the year.
| Upstream air/fuel ratio sensor | 33 ft-lb (44 Nm) |
| Exhaust manifold heat shield bolts (10 mm) | 7 ft-lb (9 Nm) |
| Wheel lug nuts (if wheel removed) | 80 ft-lb (108 Nm) |
The 22 mm sensor hex, 10 mm heat shield bolts and 33 ft-lb torque are standard across the 2012-2016 CR-V 2.4L; verify the exact sensor part number for your model year and the torque value in the Honda service manual before final tightening.
It is a wideband air/fuel ratio (A/F) sensor. The rear sensor after the catalytic converter is the conventional narrowband oxygen sensor. They are not interchangeable and use different connectors and part numbers.
A 22 mm slotted oxygen sensor socket on a 3/8 in drive. A 7/8 in wrench or 22 mm offset crowfoot will also work in tight spots, but the slotted socket is far less likely to round the hex.
Often no. On many of these you can reach the sensor from above once the engine cover and manifold heat shield are out of the way. If your hands will not fit, lifting the front and dropping the lower splash shield gives much better access from below.
Usually yes after a few drive cycles, but clearing the code with an OBD-II scanner is faster and lets you confirm the new sensor is reporting properly in live data before you call the job done.