Toyota Avalon (XX50): System Voltage Circuit Short to Ground or Open (P056014). Starter Relay Circuit Short to Battery (P061512). Brake Switch "B" Circuit Short to Battery (P070312)

Toyota Avalon (XX50) 2019-2022 Service & Repair Manual / Drivetrain / Ua80e Automatic Transmission / Transaxle / Automatic Transaxle System / System Voltage Circuit Short to Ground or Open (P056014). Starter Relay Circuit Short to Battery (P061512). Brake Switch "B" Circuit Short to Battery (P070312)

System Voltage Circuit Short to Ground or Open (P056014)

DESCRIPTION

The battery supplies electricity to the ECM even when the engine switch is off. This power allows the ECM to store data such as DTC history and freeze frame data. If the battery voltage falls below a minimum level, the stored ECM data will be cleared and the ECM will determine 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 this DTC.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Memory	Note
P056014	System Voltage Circuit Short to Ground or Open	ECM back-up power source circuit voltage is low for 3 seconds or more (1-trip detection logic).	Back-up power source circuit Battery terminals Battery ECM	Comes on	DTC stored	SAE Code: P0562

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

Note

P056014

System Voltage Circuit Short to Ground or Open

ECM back-up power source circuit voltage is low for 3 seconds or more (1-trip detection logic).

Back-up power source circuit
Battery terminals
Battery
ECM

Comes on

DTC stored

SAE Code:

P0562

HINT:

If DTC P056014 is stored, the ECM will 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	Immediate
Sequence of operation	None

TYPICAL ENABLING CONDITIONS

The monitor will run whenever the following DTCs are not stored	None
Battery voltage	8 V or more
Engine switch	On (IG)
Starter	OFF

TYPICAL MALFUNCTION THRESHOLDS

Continuous battery voltage

Less than 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.
Click here

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

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following procedure.
Perform the universal trip to clear permanent DTCs.
Click here
Perform registration and/or initialization when parts related to the automatic transaxle are replaced.
Click here

PROCEDURE

1.	INSPECT BATTERY

(a) Check that the battery is not depleted.

Click here

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 A18 ECM connector.

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

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A18-1 (BATT) - Body ground	Always	11 to 14 V

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 engine switch on (IG).

(d) Clear the DTCs.

Powertrain > Transmission > Clear DTCs

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

(f) Turn the engine switch on (IG).

(g) Turn the Techstream on.

(h) Wait 5 seconds or more.

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

Powertrain > Transmission > Trouble Codes

(j) Read the DTCs.

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

CHECK FOR INTERMITTENT PROBLEMS

5.	REPLACE ECM

(a) Replace the ECM.

Click here

PERFORM REGISTRATION

Starter Relay Circuit Short to Battery (P061512)

DESCRIPTION

While the engine is being cranked, battery voltage is applied to terminal STA of the ECM.

If the ECM detects the starter control (STA) signal while the vehicle is being driven, it determines that there is a malfunction in the STA circuit. The ECM then illuminates the MIL and stores this DTC.

This monitor runs when the vehicle is driven at 20 km/h (12 mph) or more for 20 seconds or more.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Memory	Note
P061512	Starter Relay Circuit Short to Battery	All of the following conditions are met (1-trip detection logic): The battery voltage is 10.5 V or more. The vehicle speed is 20 km/h (12 mph) or more. The engine speed is more than 1000 rpm. The starter signal is ON for 20 seconds or more.	Park/neutral position switch assembly Starter relay circuit Cranking holding function circuit Harness and connector ECM Certification ECU (Smart key ECU assembly)	Comes on	DTC stored	SAE Code: P0617

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

Note

P061512

Starter Relay Circuit Short to Battery

All of the following conditions are met (1-trip detection logic):

The battery voltage is 10.5 V or more.
The vehicle speed is 20 km/h (12 mph) or more.
The engine speed is more than 1000 rpm.
The starter signal is ON for 20 seconds or more.

Park/neutral position switch assembly
Starter relay circuit
Cranking holding function circuit
Harness and connector
ECM
Certification ECU (Smart key ECU assembly)

Comes on

DTC stored

SAE Code:

P0617

MONITOR STRATEGY

Related DTCs	P0617: Starter signal/Verify input signal
Required sensors/components (Main)	ST relay, Park/neutral position switch assembly, Certification ECU (Smart Key ECU Assembly)
Required sensors/components (Sub)	Vehicle speed sensor (VSS), Crankshaft position (CKP) sensor
Frequency of operation	Continuous
Duration	20 sec.
MIL operation	Immediate
Sequence of operation	None

TYPICAL ENABLING CONDITIONS

The monitor will run whenever the following DTCs are not stored	None
Battery voltage	10.5 V or more
Engine switch	On (IG)
Vehicle speed	20 km/h (12.43 mph) or more
Engine speed	1000 rpm or more

TYPICAL MALFUNCTION THRESHOLDS

Starter signal

CONFIRMATION DRIVING PATTERN

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

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.
Click here

Connect the Techstream to the DLC3.
Turn the engine switch on (IG) and turn the Techstream on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the engine switch off and wait for 2 minutes or more.
Turn the engine switch on (IG) and turn the Techstream on.
Start the engine.
Drive the vehicle for 20 seconds or more with the following conditions met [*1]:
- Engine speed is 1000 rpm or more.
- Vehicle speed is 20 km/h (12 mph) or more.
  HINT:
  
  [*1] : Normal judgment procedure.
  
  The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.
Stop the vehicle.
Enter the following menus: Powertrain / Transmission / Utility / All Readiness.
Input the DTC: P061512.

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

CAUTION / NOTICE / HINT

CAUTION:

Strictly observe posted speed, limits, traffic laws and road conditions.
Do not drive the vehicle with the cable of the Techstream contacting the pedals, shift lever or steering wheel.
Driving the vehicle with the cable of the Techstream contacting these areas could impede vehicle control, resulting in a serious accident.

Do not operate the Techstream while driving the vehicle.
Operating the Techstream while driving the vehicle will prevent you from paying sufficient attention to vehicle surroundings, and could result in a serious accident.

NOTICE:

Inspect the fuses for circuits related to this system before performing the following procedure.
Perform the universal trip to clear permanent DTCs.
Click here
Perform registration and/or initialization when parts related to the automatic transaxle are replaced.
Click here

PROCEDURE

1.	READ VALUE USING TECHSTREAM (STARTER SW)

(a) Connect the Techstream to the DLC3.

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

(d) Enter the following menus: Powertrain / Transmission / Data List / Starter SW.

Powertrain > Transmission > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Starter SW	Starter signal	OFF or ON	ON: Starter operating OFF: Starter not operating	-

Powertrain > Transmission > Data List

Tester Display
Starter SW

(e) Read the Data List according to the display on the Techstream.

OK:

Condition	Starter SW
Engine switch on (IG)	OFF

(f) Read the Data List according to the display on the Techstream while the vehicle is being driven with an engine speed of 1000 rpm or more at a vehicle speed of 20 km/h (12 mph) or more.

OK:

Condition	Starter SW
Driving at 20 km/h (12 mph) or more (engine speed 1000 rpm or more)	OFF

HINT:

If the result of either of the above is not as specified, proceed to the next step with the engine switch on (IG), the Techstream connected and Data List item "Starter SW" selected.

HINT:

If the starter assembly operates continuously when the engine switch is turned on (IG), proceed to the next step without reading the Data List item "Starter SW".

SYMPTOMS SIMULATION AND DTC CHECK

2.	INSPECT ST RELAY (CHECK FOR SHORT CIRCUIT)

(a) Enter the following menus: Powertrain / Transmission / Data List / Starter SW.

Powertrain > Transmission > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Starter SW	Starter signal	OFF or ON	ON: Starter operating OFF: Starter not operating	-

Powertrain > Transmission > Data List

Tester Display
Starter SW

(b) Remove the ST relay from the No. 1 engine room relay block and No. 1 junction block assembly.

Result	Proceed to
The Data List item "Starter SW" does not change from ON.	A
The Data List item "Starter SW" changes from ON to OFF.	B

HINT:

When the result of the above inspection is "The Data List item "Starter SW" does not change from ON", the ST relay is normal.
DTCs may be stored during this inspection. Check for DTCs and clear them using the Techstream.

REPLACE ST RELAY

3.	CHECK TERMINAL VOLTAGE (POWER SOURCE OF ST RELAY)

HINT:

The purpose of this step is to check for ST relay terminal voltage under abnormal conditions.

(a) Remove the ST relay from the No. 1 engine room relay block and No. 1 junction block assembly.

*1	No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
*2	ST Relay Holder

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

HINT:

Make a note of the measured voltage as it will be necessary for inspecting the change in voltage in the next step. As the next step should be conducted under the same conditions, keep the engine switch on (IG) and do not install the ST relay.
DTCs may be stored during this inspection. Check for DTCs and clear them using the Techstream.
If any voltage was measured with the engine switch on (IG), one of the following malfunctions is suspected:
- Short to +B in the circuit of a connected ECU or park/neutral position switch assembly.
- Short to +B in the wire harness.

4.	INSPECT PARK/NEUTRAL POSITION SWITCH ASSEMBLY (CHECK FOR SHORT CIRCUIT)

(a) Disconnect the C53 park/neutral position switch assembly connector.

*1	No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
*2	ST Relay Holder

(b) Measure the voltage between ST relay terminal 2 and body ground and compare it to the voltage measured in the previous step.

Result	Proceed to
The voltage between ST relay terminal 2 and body ground does not change when the connector is disconnected.	A
The voltage between ST relay terminal 2 and body ground changes when the connector is disconnected.	B

HINT:

If the voltage is the same before and after disconnecting the connector, the park/neutral position switch assembly is normal.
DTCs may be stored during this inspection. Check for DTCs and clear them using the Techstream.

REPLACE PARK/NEUTRAL POSITION SWITCH ASSEMBLY

5.	INSPECT ECM (CHECK FOR SHORT CIRCUIT)

(a) Disconnect the A18 ECM connector.

*1	No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
*2	ST Relay Holder

(b) Measure the voltage between ST relay terminal 2 and body ground and compare it to the voltage measured in the previous step.

Result	Proceed to
The voltage between ST relay terminal 2 and body ground does not change when the connector is disconnected.	A
The voltage between ST relay terminal 2 and body ground changes when the connector is disconnected.	B

HINT:

If the voltage is the same before and after disconnecting the connector, the ECM is normal.
DTCs may be stored during this inspection. Check for DTCs and clear them using the Techstream.

GO TO STEP 7

6.	CHECK HARNESS AND CONNECTOR (ECM - PARK/NEUTRAL POSITION SWITCH ASSEMBLY - SMART KEY ECU ASSEMBLY - ST RELAY)

(a) Disconnect the A18 ECM connector.

(b) Disconnect the C53 park/neutral position switch assembly connector.

(d) Remove the ST relay from the No. 1 engine room relay block and No. 1 junction block assembly.

(e) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection	Condition	Specified Condition
A18-43 (STA), C53-9 (L), A10-20 (STA) or 2 (ST relay) - Other terminals	Always	10 kΩ or higher

CHECK SMART KEY SYSTEM (CHECK FOR STA TERMINAL VOLTAGE OF SMART KEY ECU ASSEMBLY)

REPAIR OR REPLACE HARNESS OR CONNECTOR

7.	REPLACE ECM

(a) Replace the ECM.

Click here

PERFORM REGISTRATION

Brake Switch "B" Circuit Short to Battery (P070312)

DESCRIPTION

The purpose of the stop light switch signal circuit is to prevent the engine from stalling when the brakes are suddenly applied while driving in the lock-up condition.

When the brake pedal is depressed, the stop light switch assembly sends a signal to the ECM. The ECM then cancels the operation of the lock-up clutch while braking is in progress.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

Note

P070312

Brake Switch "B" Circuit Short to Battery

All of the following conditions are met (2-trip detection logic):

The engine switch is on (IG).
The battery voltage is 8 V or more.
The stop light switch remains ON while the vehicle is driven in a GO (30 km/h (19 mph) or more) and STOP (less than 3 km/h (2 mph)) pattern 5 times.

Stop light switch assembly
Short in stop light switch signal circuit
ECM

Comes on

DTC stored

SAE Code:

P0724

MONITOR DESCRIPTION

This DTC indicates that the stop light switch is remaining on. When the stop light switch remains on during GO and STOP driving, the ECM interprets this as a malfunction of the stop light switch assembly, illuminates the MIL and stores this DTC. The vehicle must GO (30 km/h (19 mph) or more) and STOP (less than 3 km/h (2 mph)) 5 times for 2 consecutive driving cycles in order for this DTC to be stored.

MONITOR STRATEGY

Related DTCs	P0724: Stop light switch/Verify switch input
Required sensors/components	Stop light switch assembly
Frequency of operation	Continuous
Duration	GO and STOP 5 times
MIL operation	2 driving cycles
Sequence of operation	None

TYPICAL ENABLING CONDITIONS

The stop light switch remains on during GO and STOP driving 5 times.

GO and STOP are defined as follows:

The monitor will run whenever the following DTCs are not stored	None
GO (Vehicle speed is 30 km/h (18.65 mph) or more)	Once
STOP (Vehicle speed is less than 3 km/h (1.86 mph))	Once
Battery voltage	8 V or more
Engine switch	On (IG)
Starter	OFF

TYPICAL MALFUNCTION THRESHOLDS

Stop light switch

CONFIRMATION DRIVING PATTERN

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

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.
Click here

Connect the Techstream to the DLC3.
Turn the engine switch on (IG) and turn the Techstream on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the engine switch off and wait for 2 minutes or more.
Turn the engine switch on (IG) and turn the Techstream on.
Start the engine.
Repeat the following procedure 5 times [*1]:
- Accelerate the vehicle to 30 km/h (19 mph) or more, depress the brake pedal and decelerate the vehicle to 3 km/h (2 mph) or less.
  HINT:
  
  [*1] : Normal judgment procedure.
  
  The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.
Stop the vehicle.
Enter the following menus: Powertrain / Transmission / Utility / All Readiness.
Input the DTC: P070312.

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 P05042B.

Click here

CAUTION / NOTICE / HINT

CAUTION:

Strictly observe posted speed, limits, traffic laws and road conditions.
Do not drive the vehicle with the cable of the Techstream contacting the pedals, shift lever or steering wheel.
Driving the vehicle with the cable of the Techstream contacting these areas could impede vehicle control, resulting in a serious accident.

Do not operate the Techstream while driving the vehicle.
Operating the Techstream while driving the vehicle will prevent you from paying sufficient attention to vehicle surroundings, and could result in a serious accident.

NOTICE:

Inspect the fuses for circuits related to this system before performing the following procedure.
Perform the universal trip to clear permanent DTCs.
Click here
Perform registration and/or initialization when parts related to the automatic transaxle are replaced.
Click here

DATA LIST

NOTICE:

In the table below, the values listed under "Normal Condition" are reference values. Do not depend solely on these reference values when deciding whether a part is faulty or not.

HINT:

Using the Techstream to read the Data List allows the values or states of switches, sensors, actuators and other items to be read without removing any parts. This non-intrusive inspection can be very useful because intermittent conditions or signals may be discovered before parts or wiring is disturbed. Reading the Data List information early in troubleshooting is one way to save diagnostic time.

(a) Warm up the engine.

(b) Turn the engine switch off.

(d) Turn the engine switch on (IG).

(e) Turn the Techstream on.

(f) Enter the following menus: Powertrain / Transmission / Data List / Stop Light SW.

(g) Read the Data List according to the display on the Techstream.

Powertrain > Transmission > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Stop Light SW	Stop light switch status	ON or OFF	ON: Brake pedal depressed OFF: Brake pedal released	-

Powertrain > Transmission > Data List

Tester Display
Stop Light SW

PROCEDURE

1.	READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

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

(d) Enter the following menus: Powertrain / Transmission / Data List / Stop Light SW.

(e) According to the display on the Techstream, read the Data List while the vehicle is being driven.

Powertrain > Transmission > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Stop Light SW	Stop light switch status	ON or OFF	ON: Brake pedal depressed OFF: Brake pedal released	-

Powertrain > Transmission > Data List

Tester Display
Stop Light SW

Result	Proceed to
Data List value is normal	A
Data List value is not normal	B

SYMPTOMS SIMULATION AND DTC CHECK

2.	CHECK STOP LIGHT SWITCH ASSEMBLY INSTALLATION

(a) Check the stop light switch assembly installation condition.

Click here

OK:

Stop light switch assembly is installed correctly.

REINSTALL STOP LIGHT SWITCH ASSEMBLY CORRECTLY

3.	INSPECT STOP LIGHT SWITCH ASSEMBLY

(a) Inspect the stop light switch assembly.

Click here

REPLACE STOP LIGHT SWITCH ASSEMBLY

4.	CHECK TERMINAL VOLTAGE (STP VOLTAGE)

(a) Disconnect the A18 ECM connector.

Brake pedal depressed

Brake Pedal Released

Front view of wire harness connector

(to ECM)

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A18-27 (STP) - Body ground	Brake pedal released	Below 1.5 V
A18-27 (STP) - Body ground	Brake pedal depressed	7.5 to 14 V

HINT:

If there is a short in the STP terminal circuit, there may be a malfunction in the circuit of a connected ECU.

REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - ECM)

5.	REPLACE ECM

(a) Replace the ECM.

Click here

PERFORM REGISTRATION

Pressure Control Solenoid "H" Actuator Stuck Off (P28167F)

Transmission Range Sensor "A" Circuit Open (P070513,P070562)

See More:

Toyota Avalon (XX50) 2019-2022 Service & Repair Manual > Sfi System: Throttle/Pedal Position Sensor/Switch "A"/"B" Voltage Correlation Signal Cross Coupled (P21352B)
DESCRIPTION Refer to DTC P012011. Click here DTC No. Detection Item DTC Detection Condition Trouble Area MIL Memory Note P21352B Throttle/Pedal Position Sensor/Switch "A"/"B" Voltage Correlation Signal Cross Coupled The difference between the output voltage of VTA1 and VTA2 is 0.02 V or less for 2 s ...