Body Electrical System > Power Tail Gate System > B1223 Vehicle Speed Sensor Failure

Component Location

General Description

Power Tailgate(hereinafter PTG) is the system which moves tailgate of vehicle by electronic motor so that user can open or close door with less force than required on manual operation. After turned on, PTG ECU monitors vehicle speed signal from VSS directly. When power gate open signal is recieved, PTG ECU checks vehicle speed before operation and if vehicle speed is above 5Km/h(3.10MPH), PTG ECU cancels power gate operation command for safty (but In case of IG "ON", if shift lever is in 'P' or 'N' position, power door operation is not prohibited).

DTC Description

The ECM sets DTC B1223 if number of ignition cycles without VSS value over 5km/h is greater than 10.

DTC Detecting Condition

Item

Detecting Condition

Possible Cause

DTC Strategy

•	Check VSS value

•	Faulty VSS

•	Open or short in signal harness

•	Open or short in power harness

•	Open or short in ground harness

Enable Conditions

Threshold value

•	Number of ignition cycles without VSS value over 5km/h is more than 10

Detecting time

FAIL SAFE

•	Inhibit open action

Signal Waveform

Schematic Diagram

Monitor Scantool Data

1.	Connect scantool to Data Link Connector(DLC).

2.	Ignition "ON" & engine "OFF" & PTG "ON"

Monitor the "Vehicle Speed Slow Status" Parameter on the Scantool. While changing vehicle speed.

Specification : vehicle speed 5Km/h(3.10MPH) or more → HIGH, 5Km/h(3.10MPH) or less → LOW

Is the measured current data within specifications?

	▶ Fault is intermittent caused by poor contact in the sensor's and/or ECM's connector or was repaired and ECM memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.
	▶ Go to "Inspection & Repair" procedure.

Terminal And Connector Inspection

1.	Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.

2.	Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.

Has a problem been found?

	▶ Repair as necessary and go to "Verification Vehicle Repair" procedure.
	▶ Go to "W/Harness Inspection" procedure.

Signal Circuit Inspection

Check for open in harness

(1)	Ignition "ON" & engine "OFF".

(2)	Disconnect "VEHICLE SPEED SENSOR" and "PTG moduel" connector.

(3)

Measure resistance between terminal of PTG and terminal of vehicle speed sensor.

Specification : Approx. 0 Ω

(4)

Is the measured resistance within specifications?

	▶ Go to "Check for short in harness" procedure.
	▶ Check for open in signal harness. Repair as necessary and go to "Verification of Vehicle Repair" procedure.

Check for short in harness

(1)	Ignition "ON" & engine "OFF"

(2)	Disconnect "VEHICLE SPEED SENSOR" connector.

(3)

Measure resistance between terminal of PTG and chassis ground.

Specification : Approx. ∞ Ω

(4)

Is the measured resistance within specifications?

	▶ Go to "Power circuit Inspection" procedure.
	▶ Check for short in signal harness. Repair as necessary and go to "Verification of Vehicle Repair" procedure.

Power Circuit Inspection

Check for open/short in harness

(1)	Ignition "OFF"

(2)	Disconnect vehicl speed sensor.

(3)	Ignition "ON"

(4)

Measure voltage between terminal of vehicle speed sensor and chassis ground.

Specification : 9~16V

(5)

Is the measured voltage within specifications?

	▶ Go to "Ground circuit Inspection" procedure.
	▶ Check for open or short in harness. Repair as necessary and go to "Verification of Vehicle Repair" procedure.

Ground Circuit Inspection

Check for open/short in harness

(1)	Ignition "OFF"

(2)	Disconnect vehicle speed sensor.

(3)	Ignition "ON"

(4)	Measure voltage between terminal of vehicle speed sensor and chassis ground.

(5)

Measure voltage between terminal "1" and "2" of vehicle speed sensor.

Specification : |(Voltage from procedure 4) - (Voltage from procedure 5)|< 200mV

(6)

Is the diffrence between two measured voltage within specifications?

	▶ Go to "Component Inspection" procedure.
	▶ Check for open/short circuit in ground harness. Repair as necessary and go to "Verification of Vehicle Repair" procedure.

Component Inspection

Check Vehicle speed sensor

(1)	Ignition "ON"

(2)	Connect the vehicle speed sensor connector

(3)

Measure waveform between terminal 3 of the sensor harness connector and chasis ground.

※ Measure waveform of vehicle speed sensor with driving the lifted vehicle

Specification : Refer Signal Waveform & Data in General Information

(4)

Is waveform measured near the specified form in General information?

	▶ Go to "Check PTG" procedure.
	▶ Substitute with a known-good vehicle speed sensor and check for proper operation. If the problem is corrected, replace vehicle speed sensor and then go to"Verification Vehicle Repair" procedure.

Check PTG

(1)	Connect scantool to Data Link Connector(DLC).

(2)	Ignition "ON" & engine "OFF"

(3)	Substitute with a known-good PTG and Check if the DTC is erased.

(4)

Is the DTC erased?

	▶ Substitute with a known-good PTG and check for proper operation. If the problem is corrected, replace PTG and then go to "Verification of Vehicle Repair" procedure.
	▶ Check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.

Verification Of Vehicle Repair

After a repair, it is essential to verify that the fault has been corrected.

1.	Connect scantool and selet "Diagnostic Trouble Codes(DTCs)" mode and then clear DTC.

2.	Operate the vehicle and monitor the DTC on the scantool.

Are any DTCs present ?

	▶ Go to the applicable troubleshooting procedure.
	▶ System is performing to specification at this time.