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P0172, P0175 FUEL INJECTION SYSTEM FUNCTION EC-245 < DTC/CIRCUIT DIAGNOSIS > [VK56DE] C D E F G H I J K L M A EC N P O P0172, P0175 FUEL INJECTION SYSTEM FUNCTION On Board Diagnosis Logic INFOID:0000000009886652 With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the theoretical mixture ratio based on the mixture ratio feedback signal from the A/F sensors 1. The ECM calcu- lates the necessary compensation to correct the offset between the actual and the theoretical ratios. In case the amount of the compensation value is extremely large (The actual mixture ratio is too rich.), the ECM judges the condition as the fuel injection system malfunction and lights up the MIL (2 trip detection logic). DTC Confirmation Procedure INFOID:0000000009886653 NOTE: If DTC Confirmation Procedure has been previously conducted, always perform the following before conduct- ing the next step. WITH CONSULT 1. Start engine and warm it up to normal operating temperature. SULT. 4. Clear the self-learning control coefficient by touching “CLEAR”. The 1st trip DTC P0172, P0175 should be detected at this stage, if a malfunction exists. If so, go to NOTE: If 1st trip DTC is not detected during above procedure, performing the following procedure is advised. a. Turn ignition switch OFF and wait at least 10 seconds. utes. Refer to the table below. Hold the accelerator pedal as steady as possible. The similar conditions to (1st trip) Freeze Frame Data means the vehicle operation that the following con- ditions should be satisfied at the same time. Sensor Input signal to ECM ECM function Actuator A/F sensor 1 Density of oxygen in exhaust gas Fuel injection control Fuel injector DTC No. Trouble diagnosis name DTC detecting condition Possible cause P0172 Fuel injection system too • Fuel injection system does not operate properly. large. (The mixture ratio is too rich.) • A/F sensor 1 P0175 Engine speed Engine speed in the freeze frame data ± 400 rpm Vehicle speed Vehicle speed in the freeze frame data ± 10 km/h (6 MPH) |