TERMINALS OF ECU CHECK TIRE PRESSURE WARNING ECU AND RECEIVER (a) Disconnect the P21 tire pressure warning ECU and receiver connector and measure the voltage or resistance on the wire harness side. 
(b) Connect the P21 tire pressure warning ECU and receiver connector. (c) Measure the voltage and resistance according to the value(s) in the table below. If the result is not as specified, the ECU may be malfunctioning. HINT: Measure the values on the wire harness side while the connector is connected. 
(d) Using an oscilloscope, check waveform 1. 
HINT: The waveform shown in the illustration is an example. If the tester displays a waveform that alternates between high and low, where high is a voltage that is between the IG power source voltage and a voltage 2.2 V lower than the IG power source voltage, and where low is a voltage of between 0 and 1.2 V, the ECU can be judged normal. |
Toyota Tundra Service Manual > Automatic Transmission System: Pressure Control Solenoid "B" Electrical (Shift Solenoid Valve SL2) (P0778)
DESCRIPTION Shifting from 1st to 6th is performed in combination with the ON and OFF operation of the shift solenoid valves SL1, SL2, S1, S2, S3, S4 and SR, which are controlled by the ECM. If an open or short circuit occurs in the shift solenoid valves, the ECM controls the remaining normal shift s ...
