UB80F (AUTOMATIC TRANSMISSION / TRANSAXLE): AUTOMATIC TRANSAXLE SYSTEM: P050031; Vehicle Speed Sensor "A" No Signal; 2021 - 2022 MY Avalon [08/2020

Last Modified: 08-21-2023	6.11:8.1.0	Doc ID: RM100000001RDS1
Model Year Start: 2021	Model: Avalon	Prod Date Range: [08/2020 - ]
Title: UB80F (AUTOMATIC TRANSMISSION / TRANSAXLE): AUTOMATIC TRANSAXLE SYSTEM: P050031; Vehicle Speed Sensor "A" No Signal; 2021 - 2022 MY Avalon [08/2020 - ]

DTC

P050031

Vehicle Speed Sensor "A" No Signal

DESCRIPTION

The speed sensor detects the wheel speed and sends the appropriate signals to the skid control ECU. The skid control ECU converts these wheel speed signals into a pulse signal and outputs it to the ECM via the combination meter. The ECM determines the vehicle speed based on the frequency of this pulse signal.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

Note

P050031

Vehicle Speed Sensor "A" No Signal

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

Park/neutral position switch D input signal is ON.
The counter gear speed is 300 rpm or more.
Any of the following conditions are met:
1. Vehicle being driven in 1st gear:
  Transmission revolution sensor (NT) value is 1450 rpm or more.
2. Vehicle being driven in 2nd gear:
  Transmission revolution sensor (NT) value is 840 rpm or more.
3. Vehicle being driven in 3rd gear:
  Transmission revolution sensor (NT) value is 540 rpm or more.
4. Vehicle being driven in 4th gear:
  Transmission revolution sensor (NT) value is 400 rpm or more.
5. Vehicle being driven in 5th gear:
  Transmission revolution sensor (NT) value is 330 rpm or more.
6. Vehicle being driven in 6th, 7th or 8th gear:
  Transmission revolution sensor (NT) value is 300 rpm or more.
No vehicle speed signal is transmitted to the ECM for 2 seconds.

Open or short in vehicle speed signal circuit
Combination meter system
ECM

Comes on

DTC stored

SAE Code:

P0500

DTC Detection Condition Patterns:

		Vehicle Condition
		Pattern 1	Pattern 2	Pattern 3	Pattern 4
Diagnostic Condition	Park/neutral position switch D input signal is ON.	○	○	○	○
	The counter gear speed is 300 rpm or more.	○	○	○	○
	When the vehicle is being driven in 1st gear, the transmission revolution sensor (NT) value is 1450 rpm or more.	○	-	-	-
	When the vehicle is being driven in 2nd gear, the transmission revolution sensor (NT) value is 840 rpm or more.	-	○	-	-
	When the vehicle is being driven in 3rd gear, the transmission revolution sensor (NT) value is 540 rpm or more.	-	-	○	-
	When the vehicle is being driven in 4th gear, the transmission revolution sensor (NT) value is 400 rpm or more.	-	-	-	○
Malfunction Condition	No vehicle speed signal is transmitted to the ECM.	○	○	○	○
Duration		2 seconds or more	2 seconds or more	2 seconds or more	2 seconds or more
Detection Logic		1-trip detection logic	1-trip detection logic	1-trip detection logic	1-trip detection logic

DTC Detection Condition Patterns:

		Vehicle Condition
		Pattern 5	Pattern 6	Pattern 7	Pattern 8
Diagnostic Condition	Park/neutral position switch D input signal is ON.	○	○	○	○
	The counter gear speed is 300 rpm or more.	○	○	○	○
	When the vehicle is being driven in 5th gear, the transmission revolution sensor (NT) value is 330 rpm or more.	○	-	-	-
	When the vehicle is being driven in 6th gear, the transmission revolution sensor (NT) value is 300 rpm or more.	-	○	-	-
	When the vehicle is being driven in 7th gear, the transmission revolution sensor (NT) value is 300 rpm or more.	-	-	○	-
	When the vehicle is being driven in 8th gear, the transmission revolution sensor (NT) value is 300 rpm or more.	-	-	-	○
Malfunction Condition	No vehicle speed signal is transmitted to the ECM.	○	○	○	○
Duration		2 seconds or more	2 seconds or more	2 seconds or more	2 seconds or more
Detection Logic		1-trip detection logic	1-trip detection logic	1-trip detection logic	1-trip detection logic

HINT:

This DTC is stored when any of the above detection patterns is met.

MONITOR DESCRIPTION

The ECM assumes that the vehicle is being driven when the transmission counter gear speed is 300 rpm or more. If there is no speed signal from the combination meter despite this condition being met, the ECM interprets this as a malfunction in the speed signal circuit, then illuminates the MIL and stores a DTC.

MONITOR STRATEGY

Related DTCs	P0500: Vehicle speed sensor/Verify pulse input
Required sensors/components (Main)	Vehicle speed sensor, Combination meter, Skid control ECU
Required sensors/components (Sub)	Transmission revolution sensor (NT), ECT sensor
Frequency of operation	Continuous
Duration	2 sec.
MIL operation	Immediately
Sequence 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
Intermediate shaft speed sensor revolution	300 rpm or more
Engine	Running
Shift change is completed before starting next shift change operation	-
R position switch	OFF
D position switch	ON
Park/neutral position switch (NSW)	OFF
Pressure control solenoid circuit fail (P08C1, P08C2, P0962, P0963, P0966, P0967, P0970, P0971, P2720, P2721, P2814, P2815, P281D, P281E) (Pending + MIL)	Not detected
Torque Converter Clutch Pressure Control Solenoid circuit fail (P2763, P2764) (Pending + MIL)	Not detected
Torque Converter Clutch Solenoid circuit fail (P2769, P2770) (Pending + MIL)	Not detected

One of the following conditions is met: Condition (A), (B), (C), (D), (E), (F), (G) or (H)

Condition (A)

ECM selected gear	1st
Turbine speed sensor revolution	1450 rpm or more

Condition (B)

ECM selected gear	2nd
Turbine speed sensor revolution	840 rpm or more

Condition (C)

ECM selected gear	3rd
Turbine speed sensor revolution	540 rpm or more

Condition (D)

ECM selected gear	4th
Turbine speed sensor revolution	400 rpm or more

Condition (E)

ECM selected gear	5th
Turbine speed sensor revolution	330 rpm or more

Condition (F)

ECM selected gear	6th
Turbine speed sensor revolution	300 rpm or more

Condition (G)

ECM selected gear	7th
Turbine speed sensor revolution	300 rpm or more

Condition (H)

ECM selected gear	8th
Turbine speed sensor revolution	300 rpm or more

Either of the following conditions is met: Condition (I) or (J)

Condition (I)

ECT

20°C (68°F) or more

ECT sensor circuit fail (P0117, P0118)

(Pending + MIL)

Not detected

Time after park/neutral position switch ON to OFF

2 sec. or more

Condition (J)

Either of the following conditions is met	(1) or (2)
(1) ECT	Less than 20°C (68°F)
(2) ECT sensor circuit fail (P0117, P0118) (Pending + MIL)	Detected
Time after park/neutral position switch ON to OFF	30 sec. or more

TYPICAL MALFUNCTION THRESHOLDS

Vehicle speed sensor signal

No 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 at 13 km/h (8 mph) or more for a total of 2 seconds or more. [*1]
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: P050031.

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 P050031.

Click here

CAUTION / NOTICE / HINT

NOTICE:

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 (VEHICLE SPEED)

(a) Connect the Techstream to the DLC3.

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

(d) Enter the following menus: Powertrain / Transmission / Data List / Vehicle Speed.

(e) Drive the vehicle.

(f) In accordance with the display on the Techstream, read the Data List.

Powertrain > Transmission > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Vehicle Speed

Vehicle speed

Min.: 0 km/h (0 mph)

Max.: 255 km/h (158 mph)

Actual vehicle speed

This is the current vehicle speed.
The vehicle speed is detected using the wheel speed sensors.
- Vehicle speed data is delayed when it is displayed. Therefore, even if the vehicle speed listed in the freeze frame data is 0 km/h (0 mph), this does not always mean that the malfunction occurred when the vehicle was stopped.

Powertrain > Transmission > Data List

Tester Display
Vehicle Speed

OK:

Vehicle speed displayed on the Techstream and speedometer display are equal.

CHECK FOR INTERMITTENT PROBLEMS

2.	CHECK COMBINATION METER SYSTEM

(a) Check the circuits that send vehicle speed signals to this system in the meter system.

Click here

(b) During inspection for the meter section, if there is an instruction that indicates to go back to inspections for each system, proceed to the next step.

3.	CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - ECM)

(a) Disconnect the G16 combination meter assembly connector.

(b) Disconnect the A64 ECM connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
G16-6 (+S) - A64-42 (SPD)	Always	Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	REPLACE ECM

(a) Replace the ECM.

Click here

PERFORM REGISTRATION