P0731-873

L110F HYBRID VEHICLE CONTROL: HYBRID CONTROL SYSTEM: P0731-873: Gear 1 Incorrect Ratio

DTC P0731-873 - Gear 1 Incorrect Ratio

DESCRIPTION

The hybrid vehicle control ECU uses the B1 and B2 brakes in the hybrid vehicle transmission assembly to switch between low and high gear.
Shifting control is performed using the line pressure circuit, B1 circuit, and B2 circuit. The hybrid vehicle control ECU detects abnormal line pressure by monitoring the operation of the fluid pressure switch in each circuit.
HINT: Although the DTC title indicates an incorrect gear ratio, DTC P0731-871 relates to a malfunction of the B2 hydraulic circuit.





HINT:
- The preceding timing chart is for the first "Control the Shift Position" active test. The chart will differ for the second or later "Control the Shift Position" active test.
- If "Hi" is selected in the first "Control the Shift Position" active test, it may take more time to shift to "Hi".

HINT: Although the DTC title indicates an incorrect gear ratio, this DTC relates to a malfunction of the B2 hydraulic circuit.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK DTC OUTPUT (HV)
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Select the following menu items: Powertrain / Hybrid Control / Trouble Codes.
(d) Check if DTCs are output.
Result:










B -- GO TO DTC CHART
A -- Continue to next step.
2. CHECK CONNECTOR CONNECTION CONDITION (HYBRID VEHICLE CONTROL ECU CONNECTOR) P0731
NG -- CONNECT SECURELY
OK -- Continue to next step.
3. CHECK CONNECTOR CONNECTION CONDITION (TRANSMISSION WIRE CONNECTOR) P0731
NG -- CONNECT SECURELY
OK -- Continue to next step.
4. CHECK HYBRID VEHICLE TRANSMISSION ASSEMBLY (SL1 SOLENOID VALVE, SL2 SOLENOID VALVE AND PRESSURE SWITCH 2) P0731
NG -- CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - TRANSMISSION WIRE)
OK -- Continue to next step.
5. CLEAR DTC P0731
NEXT -- Continue to next step.
6. SIMULATION TEST P0731
NG -- REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLY
OK -- Continue to next step.
7. CHECK FOR INTERMITTENT PROBLEMS P0731
NG -- REPAIR OR REPLACE MALFUNCTIONING PARTS, COMPONENT AND AREA
OK -- Continue to next step.
8. CHECK FLUID LEAKS P0731
NG -- REPAIR OR REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLY
OK -- REPLACE HYBRID VEHICLE CONTROL ECU
9. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - TRANSMISSION WIRE) P0731
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE HYBRID VEHICLE TRANSMISSION ASSEMBLY