Mazda CX-5 Service & Repair Manual: Heated Oxygen Sensor (HO2 S) Heater Control

Mazda CX-5 Service & Repair Manual / Engine / Control / Heated Oxygen Sensor (HO2 S) Heater Control

Outline

Based on the control of the HO2S heater, a stabilized oxygen concentration is detected even at low exhaust temperatures, and feedback control of fuel injection even at cold engine start is made possible for improved cold temperature exhaust emission performance.
Both emission performance and sensor protection have been improved by duty control of the heater according to engine operation conditions (exhaust gas temperature)

Block Diagram

Operation

The PCM operates the HO2S heater based on the following control conditions.


Output duty ratio	Control condition
0%	Engine stopped Fuel cut injection control is in engine start zone Engine coolant temperature is -10 °C {14 °F}or less Other than battery voltage of 10—16 V Within a fixed period of time after engine start (varies according to engine coolant temperature)
30%	HO2S not activated
0?100% (Determined by engine speed and charging efficiency)	Other than the above

Engine Coolant Temperature (ECT) Sensor

Purpose/Function Detects the ECT as basic information for mainly determining the fuel injection amount. Detects the ECT and inputs it to the PCM as an ECT signal. The ECT sen ...

Heated Oxygen Sensor (HO2 S) Inspection

HO2S Inspection 1. Connect the M-MDS to the DLC?2. 2. Switch the ignition ON (engine on). 3. Warm up the engine to normal operating temperature. 4. Access the following PIDs using the M-MDS.. ...

Other materials:

Hood Adjustment
Height Difference Adjustment 1. Verify that the height difference between the hood and the body is within the specification. Standard clearance a: 2.7—6.9 mm {0.11—0.27 in} b: 4.1—8.0 mm {0.17—0.31 in} 2. Disconnect the negative battery cable.. 3. Remove the ...

Warning Sound is Activated
Lights-On Reminder If lights are on and the ignition is switched to ACC or the ignition is switched off, a continuous beep sound will be heard when the driver's door is opened. NOTE • When the ignition is switched to ACC, the “Ignition Not Switched Off (STOP) Warning Beep” ove ...

Refrigerant Pressure Sensor Inspection [Full Auto Air Conditioner]
1. Install the manifold gauge. 2. Verify the high-pressure side reading of the manifold gauge. 3. Measure the terminal voltage at PCM terminal 2BB, 2AX and 2AJ 4. Using the graph below, measure and verify the terminal voltages at 2AX. 5. Follow the PCM inspection when measuring the other te ...