Toyota Tacoma (2015-2018) Service Manual: Vehicle Speed Sensor "A" No Signal (P050031)

Toyota Tacoma (2015-2018) Service Manual / Rc62f Manual Transmission / Transaxle / Manual Transmission System / Vehicle Speed Sensor "A" No Signal (P050031)

DESCRIPTION

Vehicles, which are equipped with ABS (Anti-lock Brake System), detect the vehicle speed using the skid control ECU (brake actuator assembly) and speed sensors. Each speed sensor monitors the wheel rotation speed and sends a signal to the skid control ECU. The skid control ECU converts the wheel speed signals into a 4-pulse signal and transmits it to the ECM via the combination meter assembly. The ECM determines the vehicle speed based on the frequency of the pulse signal.

HINT:

Various systems use the vehicle speed signal distributed from the combination meter assembly. Check all the components possibly related to the speed signal.
A voltage of 12 V or 5 V is output from each ECU and then input to the combination meter assembly. The signal is changed to a pulse signal at the transistor in the combination meter assembly. Each ECU controls the respective system based on the pulse signal.
If a short occurs in any of the ECUs or in the wire harness connected to an ECU, all systems using the speed signal will not operate normally.

DTC Code	DTC Detection Condition	Trouble Area	SAE
P050031	While vehicle being driven, no vehicle speed sensor signal transmitted to ECM (2 trip detection logic).	Open or short in speed signal circuit Combination meter assembly ECM	P0500

MONITOR DESCRIPTION

If there is no speed signal from the combination meter assembly even though the ECM determines that the vehicle is being driven, the ECM interprets this as a malfunction in the speed signal circuit. The ECM then stores this DTC.

WIRING DIAGRAM

Refer to Speed Signal Circuit (See page CAUTION / NOTICE / HINT ).

CAUTION / NOTICE / HINT

HINT:

After performing repair, clear the DTCs and perform the following procedure to check that DTCs are not output.

Turn the ignition switch to ON and wait for 3 seconds or more. (a)
Drive the vehicle for 6 seconds or more. (b)
Turn the ignition switch off.
Perform steps (a) and (b) again.
Check for DTCs again (See page ).

PROCEDURE

1.	READ VALUE USING TECHSTREAM (VEHICLE SPEED)

(a) Drive the vehicle and check whether the operation of the speedometer in the combination meter assembly is normal.

HINT:

The vehicle speed sensor is operating normally if the speedometer reading is normal.
If the speedometer does not operate, check it by following the diagnostic procedure for a malfunction of the speedometer.

(b) Connect the Techstream to the DLC3.

(d) Turn the Techstream on.

(e) Enter the following menus: Powertrain / Engine / Data List / Vehicle Speed.

Engine

Techstream 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. There is a delay in when the vehicle speed data 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.

Techstream 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.
- There is a delay in when the vehicle speed data 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.

(f) Drive the vehicle.

(g) According to the display on the Techstream, read the Data List.

OK:

The values displayed on the Techstream and speedometer are equal.

GO TO STEP 3

2.	CHECK DTC OUTPUT (DTC P050031)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

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

(e) Read the DTCs.

Result

Result	Proceed to
DTCs are not output	A
DTC P050031 is output	B

CHECK FOR INTERMITTENT PROBLEMS

REPLACE ECM

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

(a) Disconnect the C9 combination meter assembly connector.

(b) Disconnect the E13 ECM connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
C9-40 (+S) - E13-24 (SPD)	Always	Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	CHECK METER / GAUGE SYSTEM

(a) Proceed to Speed Signal Circuit in Meter / Gauge System (See page ).

5.	CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(d) Clear the DTCs

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

(f) Start the engine.

(g) Turn the Techstream on.

(h) Drive the vehicle for 6 seconds or more.

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

(j) Read the DTCs.

HINT:

If no DTCs (no pending DTCs) are output, the repair has been successfully completed.

END

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