Lexus NX: System Voltage (P0560)

Lexus NX Service Manual / Engine & Hybrid System / 2ar-fxe (engine Control) / Sfi System / System Voltage (P0560)

MONITOR DESCRIPTION

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

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Memory
P0560	System Voltage	An open in the ECM back up power source circuit (1 trip detection logic).	Open in back up power source circuit Auxiliary battery Auxiliary battery terminals ECM	Comes on	DTC stored

HINT:

If DTC P0560 is stored, the ECM does not store other DTCs or the data stored in the ECM is partially cleared.

MONITOR STRATEGY

Related DTCs	P0560: System voltage range check
Required Sensors/Components (Main)	ECM
Required Sensors/Components (Related)	-
Frequency of Operation	Continuous
Duration	3 seconds
MIL Operation	Immediate
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever the following DTCs are not stored

None

TYPICAL MALFUNCTION THRESHOLDS

Both of the following conditions are met	-
Stand-by RAM	Initialized
Continuous auxiliary battery voltage	Less than 3.5 V

CONFIRMATION DRIVING PATTERN

Connect the Techstream to the DLC3.
Turn the power switch on (IG) and turn the Techstream on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the power switch off and wait for at least 30 seconds.
Turn the power switch on (IG) and turn the Techstream on.
Wait 5 seconds or more.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
Read the pending DTCs.
HINT:
- If a pending DTC is output, the system is malfunctioning.
- If a pending DTC is not output, perform the following procedure.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Input the DTC: P0560.

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 is INCOMPLETE or N/A and no pending DTC is output, perform a universal trip and check for permanent DTCs.
Click here
HINT:
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTC is output, the system is normal.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following procedure.
After the power switch is turned off, there may be a waiting time before disconnecting the negative (-) auxiliary battery terminal.
Click here
When disconnecting and reconnecting the auxiliary battery.
Click here

HINT:

When disconnecting and reconnecting the auxiliary battery, there is an automatic learning function that completes learning when the respective system is used.

Click here

HINT:

Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE

1.	INSPECT AUXILIARY BATTERY

(a) Inspect the auxiliary battery.

Click here

OK:

Auxiliary battery is not depleted

CHARGE OR REPLACE AUXILIARY BATTERY

2.	CHECK AUXILIARY BATTERY TERMINAL

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

Click here

OK:

Auxiliary battery terminals are not loose or corroded.

REPAIR OR REPLACE AUXILIARY BATTERY TERMINAL

3.	CHECK TERMINAL VOLTAGE (POWER SOURCE OF ECM)

*a	Front view of wire harness connector (to 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
A35-1 (BATT) - Body ground	Always	11 to 16 V

REPAIR OR REPLACE HARNESS OR CONNECTOR (AUXILIARY BATTERY - ECM)

4.	CHECK WHETHER DTC OUTPUT RECURS (DTC P0560)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(d) Clear the DTCs.

Click here

Powertrain > Engine and ECT > Clear DTCs

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

(f) Turn the power switch on (IG) and turn the Techstream on.

(g) Wait 5 seconds or more.

(h) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

(i) Read the DTCs.

Powertrain > Engine and ECT > Trouble Codes

Result	Proceed to
DTC P0560 is output	A
DTCs are not output	B

REPLACE ECM

CHECK FOR INTERMITTENT PROBLEMS

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