Diagnostics Item 3
DIAGNOSTIC ITEM 3: Diagnose shorts between CAN_H and L lines
CAUTION:
When servicing a CAN bus line, ground yourself by touching a metal object such as an unpainted water pipe. If you fail to do so, a component connected to the CAN bus line may be damaged.
FUNCTION
If a line-to-line short is present in the CAN bus lines, this diagnosis result will be set.
TROUBLE JUDGMENT CONDITIONS
Short circuit may be present between the CAN_L and H lines when the resistance between the CAN bus lines (CAN_L and H lines) is less than 2 ohms. In addition, an open circuit may be occurred between the data link connector and the joint connector (3).
TROUBLESHOOTING HINTS
- The wiring harness may be defective [a short between CAN_H and CAN_L line, open circuit between the data link connector and the joint connector (3)]
NOTE:
The scan tool MB991958 cannot receive all the periodically sent data from each ECU by the open circuit of harness between the data link connector and the joint connector (3). In addition, the scan tool MB991958 measures the voltage itself and shows 2.5 volts due to the open circuit of harness. Therefore, it is judged as a short between CAN_H and CAN_L line.
- The connector may be defective (short in the connector)
- Each ECU may be defective (short between CAN_H and CAN_L line)
DIAGNOSIS
Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra fine probe
- MB991923: Power plant ECU Check Harness
- MB991997: ASC Check Harness
STEP 1. Check joint connector (3) C-03 and intermediate connector C-24 [ECLIPSE] or C-23 [ECLIPSE SPYDER].
CAUTION:
The strand end of the twisted wire should be within 10 cm (4.0 inches) from the connector.
For details refer to Precautions When CAN Bus Line(s) are Repaired.
Visually check if there is a short between lines due to the foreign obstacles or deformation of short pin in the connector.
Q. Is the check result normal?
YES Go to Step 2.
NO Repair the connector, or replace the joint connector (3).
STEP 2. Check the lines between the CAN_H and L lines of the front wiring harness for a short circuit. Measure the resistance at intermediate connector C-24 [ECLIPSE] or C-23 [ECLIPSE SPYDER].
CAUTION:
- A digital multimeter should be used. For details refer to Precautions When CAN Bus Line(s) are Repaired .
- The test wiring harness should be used. For details refer to Precautions When CAN Bus Line(s) are Repaired .
(1)
CAUTION:
Disconnect the negative battery terminal. For details refer to Precautions When CAN Bus Line(s) are Repaired.
Disconnect the negative battery terminal.
(2)Disconnect intermediate connector C-24 [ECLIPSE] or C-23 [ECLIPSE SPYDER], and measure the resistance at the male side (at front wiring harness side [ECLIPSE] or floor wiring harness side [ECLIPSE SPYDER]).
(3)Measure the resistance between intermediate connector terminals 11 and 12 [ECLIPSE].
OK: 120± 20 ohms
(4)Measure the resistance between intermediate connector terminals 22 and 23 [ECLIPSE SPYDER].
OK: 120± 20 ohms
Q. Is the check result normal?
YES Go to Step 3.
NO Go to Step 16.
STEP 3. Check the CAN_H and L lines between joint connector (3) and the combination meter for a short circuit. Measure the resistance at joint connector (3) C-03.
(1)Disconnect the negative battery terminal.
(2)Disconnect joint connector (3) C-03, and measure the resistance at the wiring harness side of joint connector (3) C-03.
(3)Measure the resistance between joint connector (3) terminals 4 and 15.
OK: 120± 20 ohms
Q. Is the check result normal?
YES Go to Step 4.
NO Go to Step 10.
STEP 4. Check the CAN_H and L lines between joint connector (3) and the ETACS-ECU for a short circuit. Measure the resistance at joint connector (3) C-03.
(1)Disconnect the negative battery terminal.
(2)Disconnect joint connector (3) C-03, and measure the resistance at the wiring harness side of joint connector (3) C-03.
(3)Measure the resistance between joint connector (3) terminals 5 and 16.
OK: 1 kohms or more
Q. Is the check result normal?
YES Go to Step 5.
NO Go to Step 11.
STEP 5. Check the CAN_H and L lines between joint connector (3) and the A/C-ECU for a short circuit. Measure the resistance at joint connector (3) C-03.
(1)Disconnect the negative battery terminal.
(2)Disconnect joint connector (3) C-03, and measure the resistance at the wiring harness side of joint connector (3) C-03.
(3)Measure the resistance between joint connector (3) terminals 6 and 17.
OK: 1 kohms or more
Q. Is the check result normal?
YES Go to Step 6.
NO Go to Step 12.
STEP 6. Check the CAN_H and L lines between joint connector (3) and the SRS-ECU for a short circuit. Measure the resistance at joint connector (3) C-03.
(1)Disconnect the negative battery terminal.
(2)Disconnect joint connector (3) C-03, and measure the resistance at the wiring harness side of joint connector (3) C-03.
(3)Measure the resistance between joint connector (3) terminals 3 and 14.
OK: 1 kohms or more
Q. Is the check result normal?
YES Go to Step 7.
NO Go to Step 13.
STEP 7. Check the CAN_H and L lines between joint connector (3) and the TPMS receiver for a short circuit. Measure the resistance at joint connector (3) C-03.
(1)Disconnect the negative battery terminal.
(2)Disconnect joint connector (3) C-03, and measure the resistance at the wiring harness side of joint connector (3) C-03.
(3)Measure the resistance between joint connector (3) terminals 8 and 19.
OK: 1 kohms or more
Q. Is the check result normal?
YES Go to Step 8.
NO Go to Step 14.
STEP 8. Check the CAN_H and L lines between joint connector (3) and the steering wheel sensor for a short circuit. Measure the resistance at joint connector (3) C-03.
(1)Disconnect the negative battery terminal.
(2)Disconnect joint connector (3) C-03, and measure the resistance at the wiring harness side of joint connector (3) C-03.
(3)Measure the resistance between joint connector (3) terminals 2 and 13.
OK: 1 kohms or more
Q. Is the check result normal?
YES Go to Step 9.
NO Go to Step 15.
STEP 9. Check the CAN_H and L lines between joint connector (3) and the data link connector for a short circuit. Measure the resistance at joint connector (3) C-03.
(1)Disconnect the negative battery terminal.
(2)Disconnect joint connector (3) C-03, and measure the resistance at the wiring harness side of joint connector (3) C-03.
(3)Measure the resistance between joint connector (3) terminals 7 and 18.
OK: 1 kohms or more
Q. Is the check result normal?
YES Go to Step 23.
NO Repair the wiring harness between joint connector (3) and the data link connector.
STEP 10. Check the combination meter for short circuit. Measure the resistance at combination meter connector C-04.
NOTE:
The failure could be caused by the open circuit of harness between combination meter and joint connector (3), therefore, check the open circuit as well as the short.
(1)Disconnect the negative battery terminal.
(2)Disconnect combination meter C-04, and measure the resistance at the component side of combination meter connector C-04.
(3)Measure the resistance between combination meter connector terminals 3 and 4.
OK: 120± 20 ohms
Q. Is the check result normal?
YES Check the combination meter connector, and repair if necessary. Repair the open circuit of harness between the joint connector (3) and the combination meter connector or the short between lines if the combination meter connector is normal.
NO Check the combination meter connector, and repair if necessary. If the combination meter connector is in good condition, replace the combination meter.
STEP 11. Check the ETACS-ECU for short circuit. Measure the resistance at ETACS-ECU connector C-218.
(1)Disconnect the negative battery terminal.
(2)Disconnect ETACS-ECU connector C-218, and measure the resistance at the component side of ETACS-ECU connector C-218.
(3)Measure the resistance between ETACS-ECU connector terminals 72 and 73.
OK: 1 kohms or more
Q. Is the check result normal?
YES Check the ETACS-ECU connector, and repair if necessary. If the ETACS-ECU connector is in good condition, repair the wiring harness between joint connector (3) and the ETACS-ECU connector.
NO Check the ETACS-ECU connector, and repair if necessary. If the ETACS-ECU connector is in good condition, replace the ETACS-ECU. When the ETACS-ECU is replaced, register the encrypted code. Encrypted Code Registration Criteria Table.
STEP 12. Check the A/C-ECU for short circuit. Measure the resistance at A/C-ECU connector C-14 [manual air conditioning system] or C-15 [automatic air conditioning system].
CAUTION:
A digital multimeter should be used. For details refer to Precautions When CAN Bus Line(s) are Repaired.
(1)Disconnect the negative battery terminal.
(2)Disconnect A/C-ECU connector C-14 [manual air conditioning system] or C-15 [automatic air conditioning system], and measure the resistance at the component side of A/C-ECU connector C-14 [manual air conditioning system] or C-15 [automatic air conditioning system].
(3)Measure the resistance between A/C-ECU connector terminals 5 and 6. [manual air conditioning system]
OK: 1 kohms or more
(4)Measure the resistance between A/C-ECU connector terminals 14 and 15. [automatic air conditioning system]
OK: 1 kohms or more
Q. Is the check result normal?
YES Check the A/C-ECU connector, and repair if necessary. If the A/C-ECU connector is in good condition, repair the wiring harness between joint connector (3) and the A/C-ECU connector.
NO Check the A/C-ECU connector, and repair if necessary. If the A/C-ECU connector is in good condition, replace the A/C-ECU.
STEP 13. Check the SRS-ECU for short circuit. Measure the resistance at SRS-ECU connector C-123.
(1)Disconnect the negative battery terminal.
(2)Disconnect SRS-ECU connector C-123, and measure the resistance at the component side of SRS-ECU connector C-123.
(3)Measure the resistance between SRS-ECU connector terminals 32 and 43.
OK: 1 kohms or more
Q. Is the check result normal?
YES Check the SRS-ECU connector, and repair if necessary. If the SRS-ECU connector is in good condition, repair the wiring harness between joint connector (3) and SRS-ECU connector.
NO Check the SRS-ECU connector, and repair if necessary. If the SRS-ECU connector is in good condition, replace the SRS-ECU.
STEP 14. Check the TPMS receiver for short circuit. Measure the resistance at TPMS receiver connector C-121.
(1)Disconnect the negative battery terminal.
(2)Disconnect TPMS receiver connector C-121, and measure the resistance at the component side of TPMS receiver connector C-121.
(3)Measure the resistance between TPMS receiver connector terminals 1 and 2.
OK: 1 kohms or more
Q. Is the check result normal?
YES Check the TPMS receiver connector, and repair if necessary. If the TPMS receiver connector is in good condition, repair the wiring harness between joint connector (3) and TPMS receiver connector.
NO Check the TPMS receiver connector, and repair if necessary. If the TPMS receiver connector is in good condition, replace the TPMS receiver.
STEP 15. Check the steering wheel sensor for short circuit. Measure the resistance at TPMS receiver connector C-312.
(1)Disconnect the negative battery terminal.
(2)Disconnect steering wheel sensor connector C-312, and measure the resistance at the component side of steering wheel sensor connector C-312.
(3)Measure the resistance between steering wheel sensor connector terminals 3 and 4.
OK: 1 kohms or more
Q. Is the check result normal?
YES Check the steering wheel sensor connector, and repair if necessary. If the steering wheel sensor connector is in good condition, repair the wiring harness between joint connector (3) and steering wheel sensor connector.
NO Check the steering wheel sensor connector, and repair if necessary. If the steering wheel sensor connector is in good condition, replace the steering wheel sensor.
STEP 16. Check the ECM [M/T] or PCM [A/T] for short circuit. Measure the resistance at ECM [M/T] or PCM [A/T] connector B-18.
(1)Disconnect the negative battery terminal.
(2)Disconnect ECM [M/T] or PCM [A/T] connector B-18, and measure the resistance at the component side of ECM [M/T] or PCM [A/T] connector B-18.
(3)Measure the resistance between ECM [M/T] or PCM [A/T] connector terminals 17 and 18.
OK: 120± 20 ohms
Q. Is the check result normal?
YES Check the ECM [M/T] or PCM [A/T] connector, and repair if necessary. If the ECM [M/T] or PCM [A/T] connector is in good condition, go to Step 17.
NO Check the ECM [M/T] or PCM [A/T] connector, and repair if necessary. If the ECM [M/T] or PCM [A/T] connector is in good condition, replace the ECM [M/T] or PCM [A/T].
When the ECM [M/T] or PCM [A/T] is replaced, register the encrypted code. Encrypted Code Registration Criteria Table.
STEP 17. Check the TCL/ASC-ECU for short circuit. Measure the resistance at TCL/ASC-ECU connector A-38.
(1)Disconnect the negative battery terminal.
(2)Disconnect TCL/ASC-ECU connector A-38, and measure the resistance at the component side of TCL/ASC-ECU connector A-38.
(3)Measure the resistance between TCL/ASC-ECU connector terminals 13 and 27.
OK: 1 kohms or more
Q. Is the check result normal?
YES Check the TCL/ASC-ECU connector, and repair if necessary. If the TCL/ASC-ECU connector is in good condition, go to Step 18.
NO Check the TCL/ASC-ECU connector, and repair if necessary. If the TCL/ASC-ECU connector is in good condition, replace the TCL/ASC-ECU.
STEP 18. Check the CAN_L and H lines between the ECM [M/T] or PCM [A/T] connector B-18 and the TCL/ASC-ECU connector A-38 for a short circuit. Measure the resistance at TCL/ASC-ECU connector A-38.
(1)Disconnect the negative battery terminal.
(2)Disconnect ECM connector [M/T] or PCM connector [A/T] B-18 and TCL/ASC-ECU connector A-38, and measure the resistance at the harness side of TCL/ASC-ECU connector A-38.
(3)Measure the resistance between TCL/ASC-ECU connector terminals 11 and 15.
OK: 1 kohms or more
Q. Is the check result normal?
YES [ECLIPSE] : Go to Step 19.
YES [ECLIPSE SPYDER] : Go to Step 20.
NO : Repair the wiring harness between ECM connector [M/T] or PCM connector [A/T] and TCL/ASC-ECU connector.
STEP 19. Check the CAN_L and H lines between the TCL/ASC-ECU connector and the intermediate connector for a short circuit. Measure the resistance at intermediate connector C-24.
(1)Disconnect the negative battery terminal.
(2)Disconnect intermediate connector C-24 and TCL/ASC-ECU connector A-38, and measure the resistance at the male side of intermediate connector C-24 (at front wiring harness side).
(3)Measure the resistance between intermediate connector terminals 11 and 12.
OK: 1 kohms or more
Q. Is the check result normal?
YES Repair the wiring harness between joint connector (3) and data link connector.
NO Repair the wiring harness between intermediate connector C-24 and TCL/ASC-ECU connector.
STEP 20. Check the convertible top control module for short circuit.
Measure the resistance at convertible top control module connector D-45.
(1)Disconnect the negative battery terminal.
(2)Disconnect convertible top control module connector D-45, and measure the resistance at the component side of convertible top control module connector D-45.
(3)Measure the resistance between convertible top control module connector terminals 37 and 48.
OK: 1 kohms or more
(4)Measure the resistance between convertible top control module connector terminals 38 and 49.
OK: 1 kohms or more
Q. Is the check result normal?
YES Check the convertible top control module connector, and repair if necessary. If the convertible top control module connector is in good condition, go to Step 21.
NO Check the convertible top control module connector, and repair if necessary. If the convertible top control module connector is in good condition, replace the convertible top control module.
STEP 21. Check the CAN_L and H lines between the convertible top control module connector and the TCL/ASC-ECU connector for a short circuit. Measure the resistance at TCL/ASC-ECU connector A-38.
(1)Disconnect the negative battery terminal.
(2)Disconnect convertible top control module D-45 and TCL/ASC-ECU connector A-38, and measure the resistance at the harness side of TCL/ASC-ECU connector A-38.
(3)Measure the resistance between TCL/ASC-ECU connector terminals 11 and 15.
OK: 1 kohms or more
Q. Is the check result normal?
YES Go to Step 22.
NO Check the intermediate connector C-26, and repair if necessary. If the intermediate connector C-26 in good condition, repair the wiring harness between TCL/ASC-ECU connector A-38 and convertible top control module connector D-45.
STEP 22. Check the CAN_L and H lines between the convertible top control module connector D-45 and the intermediate connector C-23 for a short circuit. Measure the resistance at intermediate connector C-23.
(1)Disconnect the negative battery terminal.
(2)Disconnect intermediate connector C-23 and convertible top control module connector D-45, and measure the resistance at the male side of intermediate connector C-23 (at front wiring harness side).
(3)Measure the resistance between intermediate connector C-23 terminals 22 and 23.
OK: 1 kohms or more
Q. Is the check result normal?
YES Repair the wiring harness between joint connector (3) and data link connector.
NO Repair the wiring harness between intermediate connector C-23 and convertible top control module connector D-45.
STEP 23. Check the CAN bus lines joint connector (3) and the data link connector. Measure the resistance between joint connector (3) C-03 and data link connector C-125.
CAUTION:
- A digital multimeter should be used. For details refer to Precautions When CAN Bus Line(s) are Repaired .
- The test wiring harness should be used. For details refer to Precautions When CAN Bus Line(s) are Repaired .
(1)
CAUTION:
Disconnect the negative battery terminal. For details refer to Precautions When CAN Bus Line(s) are Repaired.
Disconnect the negative battery terminal.
(2)Disconnect joint connector (3) C-03, and measure the resistance between the wiring harness side connector of data link connector C-125 and joint connector (3) C-03.
(3)Measure the resistance between joint connector (3) C-03 (terminal 7) and data link connector C-125 (terminal 6).
OK: 2 ohms or less
(4)Measure the resistance between joint connector (3) C-03 (terminal 18) and data link connector C-125 (terminal 14).
OK: 2 ohms or less
CAUTION:
Strictly observe the specified wiring harness repair procedure.
For details refer to Precautions on How to Repair the CAN Bus Line(s).
Q. Do all the resistances measure 2 ohms or less?
YES Repair the wiring harness between joint connector (3) and the intermediate connector.
NO Repair the wiring harness between joint connector (3) C-03 and the data link connector C-125.