2008 toyota highlander
P0354 TOYOTA - Ignition Coil 4 Primary/Secondary Circuit... Possible causes Faulty Ignition Coil 4 Ignition Coil 4 harness is open or shorted Ignition Coil 4 circuit poor electrical connection Faulty Engine Control Module (ECM)... Each ignition circuit is continuously monitored by the Engine Control Module (ECM). The test fails when the ECM does not receive a valid pulse signal from the ignition coil. Possible symptoms Engine Light ON (or Service Engine Soon Warning Light) Lack/Loss of Power Engine may be harder to start Engine hesitation Rough engine idle P0354 Toyota Description The ignition system on the vehicle uses individual ignition coils for each cylinder. The Engine Control Module (ECM) controls each ignition coil operation. The ECM sends a ON/OFF signal to energize the ignition coil to create a spark at the spark plug when a spark is required at the cylinder...........P2237 TOYOTA - A/F Sensor Bank 1 Open Circuit... Possible causes Faulty EFI Relay Faulty Air/Fuel Sensor Bank 1 Air/Fuel Sensor Bank 1 harness is open or shorted Air/Fuel Sensor Bank 1 circuit poor electrical connection Faulty Engine Control Module (ECM)... Possible symptoms Engine Light ON (or Service Engine Soon Warning Light) P2237 Toyota Description The Air-Fuel ratio (A/F) sensor provides output voltage approximately equal to the existing air-fuel ratio. The A/F sensor output voltage is used to provide feedback for the Engine Control Module (ECM) to control the air-fuel ratio. With the A/F sensor output, the ECM can determine deviation from the stoichiometric air-fuel ratio and control proper injection time. If the A/F sensor is malfunctioning, the ECM is unable to accurately control air-fuel ratio. The A/F sensor is equipped with a heater which heats the zirconia element. The heater is also controlled by the ECM. When the intake air volume is low (the temperature of the exhaust gas is low), current flows to the heater which heats the sensor to facilitate detection of accurate oxygen concentration. The A/F sensor is a planar type. Compared to a conventional type, the sensor and heater portions are narrower. Because the heat of the heater is conducted through the alumina to zirconia (of the sensor portion), sensor activation is accelerated. The code is output when there is an open or short in the A/F sensor circuit, or if A/F sensor output drops. To detect these problems, the voltage of the A/F sensor is monitored when turning the ignition switch to the ON position, and the admittance (admittance is an electrical term that indicates the ease of flow of current) is checked while driving. If the voltage of the A/F sensor is between 0.6 V and 4.5 V, it is considered normal. If the voltage is outside of the specified range, or the admittance is less than the standard value, the ECM will determine that there is a malfunction in the A/F sensor. If the same malfunction is detected in the next driving cycle, the MIL is illuminated and a DTC is set.
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