Acura TSX / Honda Accord CL. Manual - part 561

energized, and enriches the mixture to assure smooth transition to the A/C mode.

AIR FUEL RATIO (A/F) SENSOR 

The A/F Sensor operates over a wide air/fuel range. The A/F Sensor is installed upstream of the TWC, and 
sends signals to the ECM/PCM which varies the duration of fuel injection accordingly. 

Fig. 34: Identifying Air Fuel Ratio (A/F) Sensor 

BAROMETRIC PRESSURE (BARO) SENSOR 

The BARO sensor is inside the ECM/PCM. It converts atmospheric pressure into a voltage signal that modifies 
the basic duration of the fuel injection discharge. 

CAMSHAFT POSITION (CMP) SENSOR B 

CMP sensor B detects the position of the No. 1 cylinder as a reference for sequential fuel injection to each 
cylinder. 

 

2004 Acura TSX 

2004 ENGINE PERFORMANCE Fuel & Emissions Systems - TSX

  

 

Fig. 35: Cutaway View Of Camshaft Position (CMP) Sensor B 

COUNTERSHAFT SPEED SENSOR 

This sensor detects countershaft speed. 

 

2004 Acura TSX 

2004 ENGINE PERFORMANCE Fuel & Emissions Systems - TSX

  

 

Fig. 36: Cutaway View Of Countershaft Speed Sensor 

CRANKSHAFT POSITION (CKP) SENSOR 

The CKP sensor detects crankshaft speed and is used by the ECM/PCM to determine ignition timing and timing 
for fuel injection of each cylinder as well as detecting engine misfire.

 

2004 Acura TSX 

2004 ENGINE PERFORMANCE Fuel & Emissions Systems - TSX

  

 

Fig. 37: Cutaway View Of Crankshaft Position (CKP) Sensor 

ENGINE COOLANT TEMPERATURE (ECT) SENSOR 

The ECT sensor is a temperature dependent resistor (thermistor). The resistance of the thermistor decreases as 
the engine coolant temperature increases. 

 

2004 Acura TSX 

2004 ENGINE PERFORMANCE Fuel & Emissions Systems - TSX