Automobile Inspection Technology

Chapter 23 Detection Technology of Automotive Electronic Control System (8)
②Use an ohmmeter to check the continuity between the GND terminal of the tilt and telescopic ECU connector and the body ground.The ohmmeter should read on.If it does not meet the requirements, repair or replace the wiring or connector.If you meet the requirements, enter
Step ③.

③Remove the electric window circuit breaker on the No. 1 junction box, check the continuity of the circuit breaker with an ohmmeter, if not, check all the wiring and connectors connected to the electric window circuit breaker for short circuit; If conduction, check whether there is an open circuit in the junction box connector between the tilt and telescopic ECU and the battery.

3. Detection of sensor power supply circuit

The sensor power supply circuit is shown in Figure 4-56.The tilt and telescoping ECU supplies power to the position sensor, manual switch and automatic setting switch through this circuit.

Remove the tilt and telescopic ECU with wire connectors, connect the positive pole of the voltmeter to the connector terminal VC of the ECU, and the negative pole to the terminal Ei. If the reading of the meter is 0V, check the connection between the wire connector terminals VC and E1 of the ECU. Whether there is a short circuit between the wiring and the connector, if there is no short circuit, check and replace the tilt and telescopic ECU; if the reading of the meter is 5V, check whether the wiring between the ECU wire connector VC and the E1 terminal is open .If there is an open circuit, repair or replace the wiring or connector; if there is no open circuit, turn to the next circuit inspection in the fault phenomenon table 4-18.

4. Detection of tilt position sensor circuit

The tilt position sensor circuit is shown in Figure 4-57.The tilt position of the steering column is transmitted to the ECU by a position sensor with a voltage signal through this circuit. There is a constant voltage of 1V on the sensor terminal 5, and the voltage on the terminal 3 changes with the position of the steering column, and is input to the ECU by the terminal TiS.

①Remove the tilt and telescopic ECU with wire connector and the tilt position sensor with wire connector, connect the positive and negative test leads of the voltmeter to the terminals TiS and Ei of the ECU connector respectively, and slowly lift the handle of the tilt sensor High to the highest point, the meter should read 0V.With the sensor handle turned all the way down, the meter should read 5V.If the reading meets the requirements, enter the next circuit inspection in Table 4-18 of the fault phenomenon.If the requirements are not met, go to step ②.

② Unplug the wire connector of the position sensor, use an ohmmeter to detect the resistance between terminals 1 and 2 of the sensor, and the value should be 5kn; then connect the ohmmeter to terminals 3 and 2 of the sensor.When the sensor handle is brought to the highest point, the gauge should read 0n, and when the handle is turned to the lowest point, the gauge should read 5kn.

After checking various states of the sensor, if the resistance value does not meet the requirements, replace the tilt position sensor; if the resistance value meets the requirements, check the wiring or connector between the ECU and the sensor, and repair or replace the wiring or connection if there is any problem If the wiring or connector is good, check or replace the ECU.

5. Detection of tilt adjustment motor circuit

The tilt adjustment motor circuit is shown in Figure 4-58.Tilt adjustment motor terminal +B voltage is provided by ECU.When terminal TIM+ is positive and TIM- is negative, the motor rotates clockwise and the steering wheel tilts upward; otherwise, when TIM+ is negative and TIM- is positive, the motor rotates counterclockwise and the steering wheel tilts downward.

Figure 4-58 Tilt adjustment motor circuit
①Remove the tilting and telescopic ECU with wire connectors, and check the voltage between the terminals TiM+ and TiM- of the ECU wire connectors with a voltmeter. When the manual switches are respectively in the up and down tilt positions, the readings on the meter should be the battery voltage , if the reading on the meter does not meet the requirements, check or replace the ECU; if it meets the requirements, go to step ②.

② Unplug the wire connector of the tilt adjustment motor, and when connecting the positive and negative poles of the battery to terminals 1 and [-] respectively, the steering wheel should tilt downward; if the connection is reversed, the steering wheel should tilt upward.If the tilt direction does not meet the requirements, replace the adjusting motor; if it meets the requirements, go to step ③.

③ Check the wiring and connector between the tilting and telescopic ECU and the motor, if it is bad, repair or replace the wiring or connector; if it is good, go to the next circuit inspection in the fault phenomenon table 4-18.

6. Detection of telescopic position sensor circuit

The telescopic position sensor circuit is shown in Figure 4-59. The telescopic position sensor detects the telescopic position of the steering wheel and outputs it to the ECU with a voltage signal.A constant voltage of 6V is connected to the sensor terminal 5, and the voltage at the terminal 5 changes with the telescopic position of the steering wheel, and is input to the ECU through TeS.

Tilt and Telescoping ECU
①Remove the ECU and the telescopic position sensor with wire connectors, connect the positive pole of the voltmeter to the connector terminal TeS, and the negative pole to terminal E1.When the telescoping sensor lever is in the front position, the meter should read approximately 0V.When slowly moving the sensor lever to the rear position, the meter should read 5V.If the reading of the meter meets the requirements, turn to the next circuit inspection in the fault phenomenon table 4-18; otherwise, go to step ②.

② Unplug the position sensor wire connector, measure the resistance between sensor terminals 6 and 3, it should be 5kn.Then connect the ohmmeter to the terminals 5 and 3 of the sensor, move the sensor rod to the front position, the resistance between the terminals should be 0n; move the sensor rod to the rear position, the resistance should be 5kN.

After the above inspection, if the electronics of the sensor terminal does not meet the requirements, the sensor should be replaced; if the resistance meets the requirements, the wiring and connector between the ECU and the sensor should be checked, and if the wiring or connector is bad, it should be repaired or replaced; if If the wiring or connector is good, the tilt and telescopic ECU should be checked or replaced.

7. Detection of telescopic adjustment motor circuit

The telescopic adjustment motor circuit is shown in Figure 4-60.When the ECU applies a positive voltage to the motor through this circuit, that is, when the terminal TeM ten is positive and D eM- is negative, the motor rotates clockwise and the steering wheel stretches backward; otherwise, the steering wheel retracts forward.

①Remove the tilt and telescopic ECU with the wire connector, and connect the voltmeter to the TeM+ and TeM- terminals.When the manual switch is at the front position, the two terminals are forward voltage; when the manual switch is at the rear position, the two terminals are reverse voltage.The readings on the meter are all battery voltages, if they do not meet the requirements, check or replace the tilt and telescopic ECU; if they meet the requirements, go to step ②.

② Unplug the wire connector of the telescopic adjustment motor and connect the positive and negative poles of the battery to terminals 1 and [-] respectively, the steering wheel should retract forward; conversely, when the reverse battery voltage is applied, the steering wheel should extend backward.Otherwise, the telescopic adjustment motor should be replaced.If the telescoping of the steering wheel is consistent with the voltage of the added battery, enter step ③.

③ Check the wiring and connector between the tilting and telescopic ECU and the motor, if it is bad, repair or replace the wiring or connector; if it is good, go to the next circuit inspection in the fault phenomenon table 4-18.

8. Detection of automatic setting switch circuit

The automatic setting switch circuit is shown in Figure 4-61.The switch in the circuit is the main switch for automatic operation, and cannot be operated automatically when the switch is disconnected.

①Remove the tilt and telescopic ECU with wire connector, and connect the positive and negative poles of the voltmeter to the ASW and E1 terminals of the connector respectively.When the automatic switch is turned on and off, the readings on the meter should be 0V and 8-12V respectively.If it meets the requirements, go to the next circuit inspection in Table 4-18 of the fault phenomenon; if it does not meet the requirements, go to step ②.

② Unplug the automatic switch wire connector, and use an ohmmeter to measure the resistance value between the automatic switch terminal 1 and terminal 8.When the switch is turned on and off, the readings on the meter should be on and infinity respectively.If it does not meet the requirements, replace the switch, otherwise go to step ③.

③ Check the wiring and connectors between the tilting and telescopic ECU and the switch. If it is abnormal, repair or replace the wiring or connectors; if it is good, check or replace the ECU.

9. Detection of manual switch circuit

The manual switch circuit is shown in Figure 4-62. When the manual switch in the circuit is operated, different voltage signals are sent to the ECU.

①Remove the tilt and telescopic ECU with wire connectors, connect the positive and negative poles of the voltmeter to the MSW and VC terminals of the connector respectively, and operate the manual switch. The readings of the voltmeter should meet the requirements in Table 4-19.If it meets the requirements, go to the next circuit inspection in Table 4-18 of the fault phenomenon; if it does not meet the requirements, go to step ②.

② Disassemble the wire connector of the combination switch, and use an ohmmeter to detect the resistance value between terminal 2 and terminal 7 of the switch. If the measured resistance value matches the data in Table 4-19, proceed to step ③.Otherwise, the combination switch should be replaced.

③ Check the wiring and connectors between the tilting and telescopic ECU and the switch. If it is abnormal, repair or replace the wiring or connectors; if it is good, check or replace the ECU.

10. Detection of setting switch circuit

The setting switch (SET) circuit is shown in Figure 4-63.During the storage operation, press the SET switch to send a signal to the ECU, and the ECU will store the current positions of tilt, telescopic, seat, rearview mirror and seat belt tightener at the same time.

①Remove the tilt and telescopic ECU with wire connectors, and connect the positive and negative poles of the voltmeter to the MRY and ECU-E terminals respectively.When the SET switch is ON and OFF respectively, the readings on the meter should be 0V and battery voltage respectively.If it meets the requirements, go to the next circuit inspection in Table 4-18 of the fault phenomenon; if it does not meet the requirements, go to step ②.

② Unplug the wire connector of the SET switch, and use an ohmmeter to detect the resistance value between terminals 3 and 4 of the SET switch.When the SET switch is ON and OFF respectively, it should be 0n and infinite ohms respectively.If it does not meet the requirements, the SET switch should be replaced; otherwise, enter step ③.

③ Check the wiring and connectors between the tilting and telescopic ECU and the switch. If it is abnormal, repair or replace the wiring or connectors; if it is good, check or replace the ECU.

11. Detection of storage and return switch circuits

The store and return switch circuit is shown in Figure 4-64.When the SET switch is pressed (turned on), the storage command signal is sent; when the switches M1 and M2 are pressed (turned on), the return command signal is sent, and the tilt, telescopic, seat, rearview mirror and safety With tie-down for storage and return operations.

①Remove the tilt and telescopic ECU with wire connectors, connect the positive pole of the voltmeter to M1 and M2, and the negative pole to the ECU-E terminal.When the storage and return switches are ON and OFF respectively, the readings on the meter should be 0V and battery voltage respectively.If it meets the requirements, go to the next circuit inspection in Table 4-18 of fault symptoms; otherwise, go to step ②.

② Unplug the wire connector of the storage and return switch, and use an ohmmeter to check the resistance value between terminal 6 and terminal 3 of the switch.When the switch is on and off, it should be on and infinite ohms respectively.If it does not meet the requirements, the storage and return switches should be replaced; otherwise, enter step ③.

③ Check the wiring and connector between the tilting and telescopic ECU and the switch. If it is abnormal, repair or replace the wiring or connector; if it is good, check or replace it. 12. Detection of ignition switch circuit 4-65!

①Remove the tilt and telescopic ECU with wire connector, connect the positive pole of the voltmeter to the IG terminal of the connector, and ground the negative pole.When the ignition switch is ON and OFF respectively, the readings on the meter should be battery voltage and 0V respectively.If it meets the requirements, go to the next circuit inspection in Table 4-18 of fault symptoms; otherwise, go to step ②.

②Remove the ECU-IG fuse on the No. 1 junction box, and use an ohmmeter to check the conduction of the fuse.If it is not conducting, check whether all the wiring and components connected to the fuse are short-circuited; if it is conducting, check whether there is a short-circuit fault in the wiring and connector between the tilting and telescopic ECU and the battery.

13. Detection of neutral start switch circuit

The neutral start switch circuit is shown in Figure 4-66.The switch in the neutral start switch circuit detects whether the shift position is in "P" or other gears, and sends a signal to the ECU.

① Check the shift position indicator light. When the shift lever is changed to P position, the shift indicator "P" should be on; when the shift lever is changed to another position, the shift indicator "P" should be off. If the indicator light is abnormal, check or repair the circuit of the shift indicator light; if the indicator is normal, go to step ②.

②Remove the tilt and telescopic ECU with the wire connector, and check the voltage between the connector terminal P and the body ground with a voltmeter.When the shift lever is in the P position, it should be the battery voltage; when the shift lever is not in the P position, the meter should read 0V.If it meets the requirements, go to the next circuit inspection in Table 4-18 of fault symptoms; if it does not meet the requirements, go to step ③.

③ Check the wiring between the tilt and telescopic ECU and the IL3 connector and whether there is an open circuit fault in the connector.

14. Detection of gated light switch circuit

The gated light switch circuit is shown in Figure 4-67. The ECU determines whether the driver's side door light is on or off through the voltage signal of the DSW.

①When the driver's side door is opened and closed, the driver's side door light should be on and off.If it is not normal, check the door control light circuit; if it is normal, go to step ②.

②Remove the tilt and telescopic ECU with the wire connector, and use a voltmeter to detect the voltage between the connector terminal DSW and the body ground.When the driver's side door is opened and closed, the meter readings should be 0V and battery voltage respectively.If it meets the requirements, go to the next circuit inspection in Table 4-18 of fault symptoms; if it does not meet the requirements, go to step ③.

③ Check the wiring between the tilt and telescopic ECU and connector terminal BQ1 and the connector for open circuit failure.

15. Detection of unlocked alarm switch circuit

The unlocked alarm switch circuit is shown in Figure 4-68.It detects whether the key is inserted into the lock cylinder for the alarm switch. When the key is inserted, the switch is closed and sends a signal to the ECU.

(End of this chapter)