Possible causes

– Faulty Heated Oxygen Sensor (HO2S) Bank 1 Sensor 1
– Heated Oxygen Sensor (HO2S) Bank 1 Sensor 1 harness is open or shorted
– Heated Oxygen Sensor (HO2S) Bank 1 Sensor 1 circuit poor electrical conection
– Air leak in exhaust near O2 sensor

When is the code detected?

If the Powertrain Control Module (PCM) determines that the front HO2S did not switch enough times, the PCM will set the P1133 code.

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P1133 HONDA Description

The Engine Control Module (ECM) monitors the Heated Oxygen Sensor (HO2S) activity for 90 seconds after closed loop operation has begun. The ECM determines if the front HO2S is functioning properly by counting the number of HO2S-1 Lean/Rich (L/R) and Rich/Lean (R/L) switches.