Home/Isuzu/Amigo/Isuzu Amigo II (1998-2000)/Repair manual/Testing & Diagnostics/DTC P1133: HO2S INSUFFICIENT SWITCHING SENSOR 1

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DTC P1133: HO2S INSUFFICIENT SWITCHING SENSOR 1 Isuzu Amigo II

Testing & Diagnostics ~185 words

Note. For circuit reference (Схема №6)

Circuit Description

PCM monitors Heated Oxygen Sensor (HO2S) activity for 90 seconds after closed loop operation has begun. PCM determines if front HO2S is functioning properly by counting number of HO2S-1 Lean/Rich (L/R) and Rich/Lean (R/L) switches. If PCM determines that front HO2S did not switch enough times, DTC 1133 is set.

Conditions required to set DTC are

ECT is above 140°F (60°C).
Engine is operating in closed loop.
Engine running at least 2 minutes.
Canister purge duty cycle is greater than 2%.
MAF calculated airflow is 17-32 grams/sec.
Engine speed is 1500-3000 RPM.
All conditions are present for one second.
About 90 seconds after closed loop, PCM monitors oxygen sensor as it switches above and below .45 volt. If less than 12 R/L and L/R switches are detected, DTC P1133 will be set.

Diagnostic Aids

Check front HO2S heater circuits for intermittent faults. If front HO2S heater circuits are okay, replace front HO2S. If DTC cannot be duplicated, check scan tool FAILURE RECORDS to determine mileage since last DTC was set.