Code No.22, 23: Front propeller shaft speed sensor system

OPERATION

The front propeller shaft speed sensor generates 0 <=> 5 V pulse signal when the front propeller shaft rotates. The pulse signal frequency increases with a rise in front propeller shaft speed.
The front propeller shaft speed sensor is connected to the transfer-ECU (terminal No.7 and No.18) via the front propeller shaft speed sensor connector (terminal No.1 and No.2).
The transfer-ECU detects the front propeller shaft speed by the signal input to terminal No.7.
The front propeller shaft speed sensor generates the pulse signal as the hole in the front output shaft pass the magnetic tip of the sensor.

DIAGNOSIS CODE SET CONDITIONS

In the case that the input signal from the front propeller shaft speed sensor is not input during the shift from 2WD to 4WD, the code No.22 is set as the open circuit or the short circuit of the front propeller shaft speed sensor.
In the case that the input signal from the front propeller shaft speed sensor is unstable when the engage switch is ON condition, the code code No.23 is set as the open circuit or the short circuit of the front propeller shaft speed sensor.

PROBABLE CAUSES

Malfunction of the front propeller shaft speed sensor circuit
Malfunction of the front output shaft
Damaged harness wires and connectors
Malfunction of the transfer-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III data list

Item 2: Front propeller shaft speed sensor (Refer to data list reference table

Q. Is the check result normal?

	Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).

	Go to Step 2.

STEP 2. Measure the voltage at front propeller shaft speed sensor connector C-11.

(1)Disconnect the connector, and measure the voltage between terminal No.3 and earth at the wiring harness side.

(2)Turn the ignition switch to the ON position.
OK: System voltage

Q. Is the check result normal?

	Go to Step 5.

	Go to Step 3.

STEP 3. Connector check: D-401 J/B connector, D-225, D-229 intermediate connector.

Check for the contact with terminals.

Q. Is the check result normal?

	Go to Step 4.

	Repair the defective connector.

STEP 4. Check the harness between front propeller shaft speed sensor connector C-11 terminal No.3 and J/B connector D-401 terminal No.12.

Check the power supply line for short or open circuit.

Q. Is the check result normal?

	Go to Step 5.

	Repair the wiring harness.

STEP 5. Measure the voltage at front propeller shaft speed sensor connector C-11.

(1)Disconnect the connector, and measure the voltage between terminal No.2 and earth at the wiring harness side.

(2)Turn the ignition switch to the ON position.
OK: 4.5 - 4.9 V

Q. Is the check result normal?

	Go to Step 11.

	Go to Step 6.

STEP 6. Measure the voltage at transfer-ECU connector D-124.

(1)Disconnect front propeller shaft speed sensor connector C-11.

(2)Turn the ignition switch to the ON position.

(3)Measure the voltage between transfer-ECU connector D-124 terminal No.7 and earth.
OK: 4.5 - 4.9 V

Q. Is the check result normal?

	Go to Step 7.

	Go to Step 9.

STEP 7. Connector check: C-11 front propeller shaft speed sensor connector, D-124 transfer-ECU connector.

Check for the contact with terminals.

Q. Is the check result normal?

	Go to Step 8.

	Repair the defective connector.

STEP 8. Check the harness between front propeller shaft speed sensor connector C-11 terminal No.2 and transfer-ECU connector D-124 terminal No.7.

Check the output line for open circuit.

Q. Is the check result normal?

	Go to Step 19.

	Repair the wiring harness.

STEP 9. Connector check: C-11 front propeller shaft speed sensor connector, D-124 transfer-ECU connector.

Repair the defective connector.

Q. Is the check result normal?

	Go to Step 10.

	Repair the defective connector.

STEP 10. Check the harness between front propeller shaft speed sensor connector C-11 terminal No.2 and transfer-ECU connector D-124 terminal No.7.

Check the output line for short circuit.

Q. Is the check result normal?

	Go to Step 11.

	Repair the wiring harness.

STEP 11. Measure the resistance at front propeller shaft speed sensor connector C-11.

Disconnect the connector, and measure the resistance between terminal No.1 and earth at the wiring harness side.

OK: Continuity (2 Ω or less)

Q. Is the check result normal?

	Go to Step 16.

	Go to Step 12.

STEP 12. Measure the resistance at transfer-ECU connector D-124.

(1)Do not disconnect front propeller shaft speed sensor connector C-11.

(2)Measure the voltage between transfer-ECU connector D-124 terminal No.18 and earth.
OK: Continuity (2 Ω or less)

Q. Is the check result normal?

	Go to Step 13.

	Go to Step 15.

STEP 13. Connector check: C-11 front propeller shaft speed sensor connector, D-124 transfer-ECU connector.

Check for the contact with terminals.

Q. Is the check result normal?

	Go to Step 14.

	Repair the defective connector.

STEP 14. Check the harness between front propeller shaft speed sensor connector C-11 terminal No.1 and transfer-ECU connector D-124 terminal No.18.

Check the earth line for open circuit.

Q. Is the check result normal?

	Go to Step 16.

	Repair the wiring harness.

STEP 15. Connector check: D-124 transfer-ECU connector.

Check for the contact with terminals.

Q. Is the check result normal?

	Replace the transfer-ECU.

	Repair the defective connector.

STEP 16. Measure the output wave pattern of the front propeller shaft speed sensor at transfer-ECU connector D-124 (using an oscilloscope).

(1)Start the engine and drive the vehicle at constant speed of 30 km/h.

(2)Connect an oscilloscope, and measure the voltage between transfer-ECU connector D-124 terminal No.7 and No.18.

(3)Check the front propeller shaft speed sensor waveform.
OK: A wave pattern such as the one shown on (Inspection Procedure Using an Oscilloscope ) should be output, and the maximum value should be 4.8 V or more and the minimum value should be 0.8 V or less. There should be no noise in the output wave pattern.

Q. Is the check result normal?

	Go to Step 19.

	Go to Step 17.

STEP 17. Replace the front propeller shaft speed sensor.

(1)Replace the front propeller shaft speed sensor.

(2)Test drive the vehicle.

(3)Check if the diagnosis code is set.

Q. Is diagnosis code No.22 or No.23 set?

	Go to Step 18.

	The inspection is complete.

STEP 18. Replace the sensor rotor.

(1)Replace the sensor rotor.

(2)Test drive the vehicle.

(3)Check if the diagnosis code is set.

Q. Is diagnosis code No.22 or No.23 set?

	Eliminate the cause of the noise.

	The inspection is complete.

STEP 19. M.U.T.-III data list

Item 2: Front propeller shaft speed sensor (Refer to data list reference table

Q. Is the check result normal?

	Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).

	Replace the transfer-ECU.