Tools you need for O2 sensor on a 2013-2017 Honda Accord

On the 9th-gen Accord the part everyone calls the upstream O2 sensor is really a wideband air/fuel ratio sensor, and it threads into the exhaust manifold with the same 22 mm (7/8 in) hex as a normal O2 sensor. The work itself is simple: unplug it, unscrew it, screw the new one in to 33 ft-lb. The difficulty is entirely about access and about whether ten years of road salt has welded the sensor into the boss.

The 2.4L K24W has one upstream sensor at the rear of the engine in the head-integrated manifold; the 3.5L V6 has two, and the rear-bank one is the one that eats afternoons. The single most common mistake is installing a cheap universal or narrowband sensor: the Accord's ECU expects a Denso-type wideband, and the wrong sensor will either throw a heater-circuit code or make the fuel trims wander. Buy the correct bank-specific part.

Complete tool and parts list

Differences within the 2013-2017 generation

Both engines use the same 22 mm (7/8 in) sensor hex and the same 10 mm fasteners for shields and brackets. The 2.4L K24W has a single upstream AFR sensor in the integrated exhaust manifold at the rear of the head. The 3.5L J35Y has two upstream sensors with different part numbers and harness lengths: bank 1 at the front manifold, bank 2 at the firewall-side manifold, which usually requires an offset 7/8 in sensor wrench and work from underneath.

Torque specs

How the job goes

1. Read the codes and confirm the failing sensor: P0135/P0133/P2238 range points to the upstream (AFR) sensor; on the V6, P0134-type bank 1 codes are the front manifold, bank 2 is the rear manifold sensor.
2. With the engine cold, spray penetrating oil on the sensor threads and let it sit; overnight is ideal on a rusty car.
3. Disconnect the negative battery terminal (10 mm) if you want to avoid stored codes and accidental shorts.
4. Remove the plastic engine cover and any intake/harness cover in the way. On the 2.4L the sensor sits at the back of the engine in the integrated exhaust manifold; on the 3.5L the bank 1 sensor is at the front manifold and bank 2 is at the rear, reached from below.
5. Trace the sensor lead to its connector, unclip it from its bracket, press the lock tab with a pick and separate the connector. Do not pull on the wires.
6. Raise the front of the car, set it on jack stands, and remove the lower splash shield push-pins/10 mm bolts for access from below if needed.
7. Unbolt the manifold heat shield (10 mm) if it blocks the socket.
8. Fit the 22 mm slotted O2 sensor socket over the sensor with the wire through the slot, and break it loose counterclockwise. Use the offset wrench and a breaker bar if space is tight; steady pressure, not jerking, to avoid rounding it.
9. Unthread the sensor and feed the harness out along the same route as original. Photograph the routing first.
10. Wire-brush the threads in the manifold boss and check they are clean and undamaged.
11. Thread the new sensor in by hand. If the threads are not pre-coated, apply a thin film of sensor-safe anti-seize to the threads only, nothing on the sensing tip.
12. Torque to 33 ft-lb (44 Nm) with the torque wrench.
13. Route the harness exactly as it came out, clear of the exhaust and moving parts, and reconnect the connector until it clicks. Reinstall all clips and brackets.
14. Reinstall heat shield, splash shield and engine cover. Lower the car.
15. Reconnect the battery, start the engine, let it idle to operating temperature, and clear any stored codes.
16. Verify with the scan tool: the AFR sensor should show current/lambda activity around 1.00 at idle, and the readiness monitors should set after a drive cycle.

Watch out

The 22 mm (7/8 in) sensor size and 33 ft-lb (44 Nm) torque are standard for Honda AFR sensors of this era, but confirm the exact torque and the bank-specific part number for your engine in the factory service manual or on the parts listing before installing.

Other jobs on the 2013-2017 Honda Accord

Oxygen Sensor Replacement on other vehicles