P0A1D-142

P112 HYBRID VEHICLE CONTROL: HYBRID CONTROL SYSTEM: P0A1D-142: Hybrid Powertrain Control Module

DTC P0A1D-142 - Hybrid Powertrain Control Module

DESCRIPTION

When the ST turned ON in the ignition switch on the previous model, the ignition switch transmitted the ST signal to the HV control ECU.
The new Prius has adopted a push button start system. When the driver pushes on the power switch while depressing the brake pedal, the power source control ECU transmits the ST signal to the HV control ECU.





The HV control ECU monitors the ST signal to detect malfunction. If the ST signal is shorted to the +B power supply, the ST will be constantly ON, which will cause the HV system to start by merely turning the power switch ON (IG). The HV control ECU monitors the ST signal to prevent this from occurring.






MONITOR DESCRIPTION

The HV control ECU monitors an ST signal input from the power source control ECU. If the ST signal is shorted to the +B power supply, the HV control ECU interprets this as the ST signal error, and then illuminates the MIL and sets a DTC.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS





COMPONENT OPERATING RANGE





WIRING DIAGRAM





INSPECTION PROCEDURE
HINT: This DTC may be stored if fuse AM2 is open.

PROCEDURE

1. CHECK HYBRID VEHICLE CONTROL ECU (ST2 VOLTAGE)




(a) Measure the voltage according to the value(s) in the table below.
Standard voltage:






OK -- CHECK FOR INTERMITTENT PROBLEMS
NG -- Continue to next step.

2. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - POWER SOURCE CONTROL ECU)




(a) Disconnect the H14 HV control ECU connector.




(b) Disconnect the P6 power source control ECU connector.
(c) Measure the voltage between the terminal of the HV control ECU connector or power source control ECU and body ground with the power switch turned OFF.
Standard voltage:





(d) Reconnect the power source control ECU connector.
(e) Reconnect the HV control ECU connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

3. CHECK HYBRID VEHICLE CONTROL ECU (ST2 VOLTAGE)
(a) Disconnect the P6 power source control ECU connector.




(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:






NG -- REPLACE HYBRID VEHICLE CONTROL ECU
OK -- REPLACE POWER SOURCE CONTROL ECU