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Home >> Toyota >> 2001 >> Sienna CE >> Repair and Diagnosis >> External Pages >> Different car >> Section 450 (Automatic Transmission - Diagnosis) >> Circuit Inspection >> DTC P0973: Shift Solenoid "A" Control Circuit Low (Shift Solenoid Valve S1); DTC P0974: Shift Solenoid "A" Control Circuit High (Shift Solenoid Valve S1); DTC P0976: Shift Solenoid "B" Control Circuit Low (Shift Solenoid Valve S2); DTC P0977: Shift Solenoid "B" Control Circuit High (Shift Solenoid Valve S2); DTC P0979: Shift Solenoid "C" Control Circuit Low (Shift Solenoid Valve S3); DTC P0980: Shift Solenoid "C" Control Circuit High (Shift Solenoid Valve S3) >> Circuit Description

Circuit Description

WARNING: This page is about a different car, the 2003 Lexus LS 430. However, it is still accessible from the selected car via links, so may be relevant.

Shifting from 1 st to 5th is performed in combination with ON and OFF of the shift solenoid valves No. 1, No. 2 and No. 3 controlled by 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 operated smoothly (Fail safe function).

HINT:

Check the shift solenoid valve No. 1 when DTC P0973 and P0974 is output, check the shift solenoid valve No. 2 when DTC P0976 and P0977 is output and check the shift solenoid valve No. 3 when DTC P0979 and P0980 is output.

DTC CONDITION DETECTION CHART

DTC No. DTC Detection Condition Trouble Area
P0973 ECM detects short in solenoid valve No. 1 circuit 4 times when solenoid valve No. 1 is operated (1-trip detection logic)
  • Short in shift solenoid valve No. 1 circuit
  • Shift solenoid valve No. 1
  • ECM
P0974 ECM detects open in solenoid valve No. 1 circuit 4 times when solenoid valve No. 1 is not operated (1-trip detection logic)
  • Open in shift solenoid valve No. 1 circuit
  • Shift solenoid valve No. 1
  • ECM
P0976 ECM detects short in solenoid valve No. 2 circuit 4 times when solenoid valve No. 2 is operated (1-trip detection logic)
  • Short in shift solenoid valve No. 2 circuit
  • Shift solenoid valve No. 2
  • ECM
P0977 ECM detects open in solenoid valve No. 2 circuit 4 times when solenoid valve No. 2 is not operated (1-trip detection logic)
  • Open in shift solenoid valve No. 2 circuit
  • Shift solenoid valve No. 2
  • ECM
P0979 ECM detects short in solenoid valve No. 3 circuit 4 times when solenoid valve No. 3 is operated (1-trip detection logic)
  • Short in shift solenoid valve No. 3 circuit
  • Shift solenoid valve No. 3
  • ECM
P0980 ECM detects open in solenoid valve No. 3 circuit 4 times when solenoid valve No. 3 is not operated (1-trip detection logic)
  • Open in shift solenoid valve No. 3 circuit
  • Shift solenoid valve No. 3
  • ECM

Fail Safe Function:

If either of the shift solenoid valve circuits develops an open or short, the ECM turns the other shift solenoid ON and OFF to shift to the gear positions shown in the table below. The ECM also turns the shift solenoid valve SL OFF at the same time. If both solenoids are malfunctioning, hydraulic control cannot be performed electronically and must be done manually.

Manual shifting as shown in the following table must be done (In the case of a short circuit, the ECM stops sending current to the short circuited solenoid).

MALFUNCTION CHART

Position Normal Shift Solenoid No. 1 Malfunction Shift Solenoid No. 2 Malfunction Shift Solenoid No. 3 Malfunction
Shift Solenoid Gear Shift Solenoid Gear Shift Solenoid Gear Shift Solenoid Gear
No. 1 No. 2 No. 3 No. 1 No. 2 No. 3 No. 1 No. 2 No. 3 No. 1 No. 2 No. 3
D ON OFF ON 1 X OFF-->ON ON-->OFF 4-->3 ON X OFF 1 ON OFF X 1
OFF ON OFF 3 X ON OFF 3 OFF X OFF-->ON 5-->4 OFF ON X 3
OFF OFF ON 4 X OFF ON 4 OFF X ON 4 OFF OFF X 5
OFF OFF OFF 5 X OFF OFF 5 OFF X OFF 5 OFF OFF X 5
4 ON OFF ON 1 X OFF-->ON ON-->OFF 4-->3 ON X OFF 1 ON OFF X 1
OFF ON OFF 3 X ON OFF 3 OFF X OFF-->ON 5-->4 OFF ON X 3
OFF OFF ON 4 X OFF ON 4 OFF X ON 4 OFF OFF X 5
3 ON OFF ON 1 X OFF-->ON ON 4-->3 ON X OFF 1 ON OFF X 1
OFF ON ON 3 X ON ON 3 OFF X ON 4 OFF ON X 3
OFF OFF ON 4 X OFF ON 4 OFF X ON 4 OFF OFF X 4
2 ON OFF ON 1 X OFF-->ON ON 3 ON X ON 1 ON OFF X 1
OFF ON ON 3 X ON ON 3 OFF X ON 3 OFF ON X 3
L ON OFF OFF 1 X OFF-->ON OFF-->ON 3 ON X OFF 1 ON OFF X 1
MALFUNCTION CHART

Position Shift Solenoid No. 1 and No. 2 Malfunction Shift Solenoid No. 1 and No. 3 Malfunction Shift Solenoid No. 2 and No. 3 Malfunction Shift Solenoid No. 1, No. 2 and No. 3 Malfunction
Shift Solenoid Gear Shift Solenoid Gear Shift Solenoid Gear Shift Solenoid Gear
No. 1 No. 2 No. 3 No. 1 No. 2 No. 3 No. 1 No. 2 No. 3 No. 1 No. 2 No. 3
D X X ON 4-->4 X OFF-->ON X 5-->3 ON X X 1 X X X 5
X X OFF-->ON 5-->4 X ON X 3 OFF X X 5 X X X 5
X X ON 4 X OFF X 5 OFF X X 5 X X X 5
X X OFF 5 X OFF X 5 OFF X X 5 X X X 5
4 X X ON 4-->4 X OFF-->ON X 5-->3 ON X X 1 X X X 5
X X OFF-->ON 5-->4 X ON X 3 OFF X X 5 X X X 5
X X ON 4 X OFF X 5 OFF X X 5 X X X 5
3 X X ON 4 X OFF-->ON X 4-->3 ON X X 1 X X X 4
X X ON 4 X ON X 3 OFF X X 4 X X X 4
X X ON 4 X OFF X 4 OFF X X 4 X X X 4
2 X X ON 3 X OFF-->ON X 3 ON X X 1 X X X 3
X X ON 3 X ON X 3 OFF X X 3 X X X 3
L X X OFF-->ON 3 X OFF-->ON X 3 ON X X 1 X X X 3
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