Toyota Tacoma 2015-2018 Service Manual: System Voltage Circuit Short to Ground or Open (P056014)

Toyota Tacoma 2015-2018 Service Manual / Ac60e Automatic Transmission / Transaxle / Automatic Transmission System(for 2gr-fks) / System Voltage Circuit Short to Ground or Open (P056014)

DESCRIPTION

The battery supplies power to the ECM even when the ignition switch is off. This power allows the ECM to store data such as DTC history, freeze frame data and fuel trim values. If the battery voltage falls below a minimum level, the ECM data is cleared and the ECM determines that there is a malfunction in the power supply circuit. The next time the engine is started, the ECM will illuminate the MIL and store the DTC.

DTC Code	DTC Detection Condition	Trouble Area	SAE
P056014	Open or short in ECM back-up power source circuit for 3 seconds or more (1 trip detection logic).	Back-up power source circuit Battery terminals Battery ECM	P0562

HINT:

If DTC P056014 is stored, the ECM does not store other DTCs.

MONITOR STRATEGY

Related DTCs	P0562: ECM system voltage/Range check (Low voltage)
Required Sensors/Components (Main)	ECM
Required Sensors/Components (Sub)	-
Frequency of Operation	Continuous
Duration	3 sec.
MIL Operation	Immediately (MIL illuminated after next engine start)
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

The monitor will run whenever the following DTCs are not stored	None
Battery voltage	8 V or higher
Ignition switch	ON
Starter	OFF

TYPICAL MALFUNCTION THRESHOLDS

Continuous battery voltage

Below 3.5 V

CONFIRMATION DRIVING PATTERN

HINT:

After repairs have been completed, clear the DTCs and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.
When clearing the permanent DTCs, refer to the Clear Permanent DTC procedure (See page ).

Connect the Techstream to the DLC3.
Turn the ignition switch to ON and turn the Techstream on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the ignition switch off and wait for 2 minutes or more.
Turn the ignition switch to ON and turn the Techstream on.
Wait for 3 seconds or more with the ignition switch to ON. [*1]
HINT:

[*1] : Normal judgment procedure.

The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.
Enter the following menus: Powertrain / Transmission / Utility / All Readiness.
Input the DTC: P056014.

Check the DTC judgment result.

Techstream Display	Description
NORMAL	DTC judgment completed System normal
ABNORMAL	DTC judgment completed System abnormal
INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions
N/A	Unable to perform DTC judgment Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

HINT:

If the judgment result shows NORMAL, the system is normal.
If the judgment result shows ABNORMAL, the system has a malfunction.
If the judgment result shows INCOMPLETE or N/A, perform the normal judgment procedure again.

WIRING DIAGRAM

Refer to SFI system DTC P056014 (See page CAUTION / NOTICE / HINT ).

CAUTION / NOTICE / HINT

NOTICE:

Perform the universal trip to clear permanent DTCs (See page ).
Perform registration and/or initialization when parts related to the automatic transmission are replaced (See page ).
Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

1.	INSPECT BATTERY

(a) Inspect that the battery is not depleted (See page OK: ).

OK:

Battery is not depleted

CHARGE OR REPLACE BATTERY

2.	CHECK BATTERY TERMINAL

(a) Check that the battery terminals are not loose or corroded.

OK:

Battery terminals are not loose or corroded

REPAIR OR REPLACE BATTERY TERMINAL

3.	CHECK TERMINAL VOLTAGE (POWER SOURCE OF ECM)

(a) Disconnect the ECM connector.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
E14-2 (BATT) - Body ground	Always	11 to 14 V

Text in Illustration

*a	Rear view of wire harness connector (to ECM)

REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - ECM)

4.	CHECK WHETHER DTC OUTPUT RECURS (DTC P056014)

(a) Connect the Techstream to the DLC3.

(b) Turn the Ignition switch ON.

(d) Clear the DTCs (See page (e) Turn the Ignition switch off and wait for at least 30 seconds. ).

(e) Turn the Ignition switch off and wait for at least 30 seconds.

(f) Turn the Ignition switch ON.

(g) Turn the Techstream on.

(h) Wait 5 seconds or more.

(i) Enter the following menus: Powertrain / Transmission / Trouble Codes.

(j) Read the DTCs using the Techstream.

Result:

Result	Proceed to
DTC P056014 is output	A
DTC is not output	B

REPLACE ECM

CHECK FOR INTERMITTENT PROBLEMS

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