Toyota Corolla Cross: Vehicle Speed Sensor "A" No Signal (P050031)

DESCRIPTION

• w/ Smart Key System
  • Vehicles, which are equipped with ABS (Anti-lock Brake System), detect the vehicle speed using the skid control ECU (brake actuator assembly) and speed sensor. The speed sensor monitors the wheel rotation speed and sends a signal to the skid control ECU. The skid control ECU detects the wheel speed of all 4 wheels and outputs a 4-pulse signal to the ECM via the certification ECU (smart key ECU assembly) and combination meter assembly. The ECM determines the vehicle speed based on the frequency of the pulse signal.
• w/o Smart Key System
  • Vehicles, which are equipped with ABS (Anti-lock Brake System), detect the vehicle speed using the skid control ECU (brake actuator assembly) and speed sensor. The speed sensor monitors the wheel rotation speed and sends a signal to the skid control ECU. The skid control ECU converts the wheel speed signal 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 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.

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 illuminates the MIL and stores this DTC.

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

CONFIRMATION DRIVING PATTERN

HINT:

• After repair has been completed, clear the DTC and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.

  Click here

• When clearing the permanent DTCs, refer to the "CLEAR PERMANENT DTC" procedure.

  Click here

1. Connect the GTS to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the GTS on.
4. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
5. Turn the ignition switch off and wait for at least 30 seconds.
6. Turn the ignition switch to ON [A].
7. Turn the GTS on.
8. Start the engine [B].
9. Drive the vehicle at 24 km/h (15 mph) or more for a total of 30 seconds or more [C].

   CAUTION:

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

10. Stop the vehicle.
11. Enter the following menus: Powertrain / Engine / Trouble Codes [D].
12. 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.
13. Enter the following menus: Powertrain / Engine / Utility / All Readiness.
14. Proceed to the next screen and enter the DTC to be checked.
15. Check the DTC judgment result.

    GTS 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

    HINT:

    • If the judgment result is NORMAL, the system is normal.
    • If the judgment result is ABNORMAL, the system has a malfunction.
    • If the judgment result is INCOMPLETE, perform steps [C] through [D] again.
    • [A] to [D]: Normal judgment procedure.

      The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.

    • When clearing the permanent DTCs, do not disconnect the cable from the auxiliary battery terminal or attempt to clear the DTCs during this procedure, as doing so will clear the universal trip and normal judgment histories.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

HINT:

Read Freeze Frame Data using the GTS. 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

HINT:

This procedure confirms whether the speedometer is operating correctly.

(a) Enter the following menus.

(b) Drive the vehicle.

(c) Read the value displayed on the GTS.

B

CHECK FOR INTERMITTENT PROBLEMS

A

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

Click here

NEXT

(a) Disconnect the combination meter assembly connector.

(b) Disconnect the ECM connector.

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

Standard Resistance:

OK

REPLACE ECM

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

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