A340E Automatic Transmission System

A340E AUTOMATIC TRANSMISSION: AUTOMATIC TRANSMISSION SYSTEM: P0973,P0974,P0976,P0977: Shift Solenoid "A" Control Circuit Low (Shift Solenoid Valve S1)
P0977 - Shift Solenoid "B" Control Circuit High (Shift Solenoid Valve S2)

DESCRIPTION

Shifting from 1st to 4th is performed in combination with the ON and OFF operation of the shift solenoid valves S1 and S2 which are controlled by the ECM. If an open or short circuit occurs in either of the shift solenoid valves, the ECM controls the remaining normal shift solenoid valve to allow the vehicle to be driven smoothly. (In case of an open or short circuit, the ECM stops sending current to the circuit.)

For details, refer to the fail-safe chart Fail-Safe Chart.





MONITOR DESCRIPTION

The ECM controls the gear shift by turning the shift solenoid valves "ON/OFF". When there is an open or short circuit in either shift solenoid valve circuit, the ECM detects the problem, illuminates the MIL and stores a DTC. Then the ECM performs the fail-safe function and turns the other shift solenoid valve in good condition "ON/OFF". (In case of an open or short circuit, the ECM stops sending current to the circuit.)

MONITOR STRATEGY

P0973, P0974:





P0976, P0977:





TYPICAL ENABLING CONDITIONS

P0973: Range check (Low resistance)





P0974: Range check (High resistance)





P0976: Range check (Low resistance)





P0977: Range check (High resistance)





TYPICAL MALFUNCTION THRESHOLDS

P0973: Range check (Low resistance)





P0974: Range check (High resistance)





P0976: Range check (Low resistance)





P0977: Range check (High resistance)





COMPONENT OPERATING RANGE

P0973, P0974:





P0976, P0977:





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
Perform the universal trip to clear permanent DTCs DTC Check / Clear.

HINT
The shift solenoid valve S1 or S2 is turned on/off normally when the shift lever is in the D position:





PROCEDURE

1. INSPECT TRANSMISSION WIRE (S1/S2)





(a) Disconnect the transmission wire connector from the transmission.

(b) Measure the resistance according to the value(s) in the table below.

Standard resistance:





NG -- INSPECT SHIFT SOLENOID VALVE (S1/S2)
OK -- Continue to next step.

2. CHECK HARNESS AND CONNECTOR (TRANSMISSION WIRE - ECM)





(a) Connect the transmission connector to the transmission.

(b) Disconnect the ECM connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE ECM

3. INSPECT SHIFT SOLENOID VALVE (S1/S2)





(a) Remove the shift solenoid valve S1 or S2.

(b) Measure the resistance according to the value(s) in the table below.

Standard resistance:





(c) Connect the battery's positive (+) lead to the terminal of the solenoid valve connector, and the negative (-) lead to the solenoid body. Then check that the valve moves and makes an operating noise.

OK:

Valve moves and makes an operating noise.

NG -- REPLACE SHIFT SOLENOID VALVE (S1/S2)

OK -- REPAIR OR REPLACE TRANSMISSION WIRE Removal