Diagnostic Item 16

DIAGNOSTIC ITEM 16: Diagnose CAN bus lines thoroughly

Part 1:

Part 1:

Part 2:

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
The diagnostic result demonstrates that "Diagnose CAN bus lines thoroughly" when the trouble spot cannot be localized by the CAN bus diagnostics.

TROUBLE JUDGEMENT CONDITIONS
Scan tool MB991958 judges "Diagnose CAN bus lines thoroughly" when any diagnostic item from 3 to 11 cannot be identified.

TROUBLESHOOTING HINTS
- Each ECU may be defective
- The wiring harness may be defective
- The connector may be defective

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A

- MB991970: ABS Check Harness

STEP 1. Check the CAN bus lines at the data link connector. Measure the resistance at the data link connector C-125.

CAUTION:
- A digital multimeter should be used.
- The test wiring harness should be used.

CAUTION: Disconnect the negative battery terminal.







1. Disconnect the negative battery terminal.
2. Measure the resistance at the data link connector.
3. Measure the resistance between data link connector terminals 6 and 14.

OK: 60 ± 10 ohms

Q: How much resistance is measured?

YES: (60 ± 10 ohms) : Go to Step 2.

NO: (2 ohms or less or 200 ohms or more) : Diagnostic Item 3: Check the CAN_H and L lines for a short circuit.

NO: (other than them resistance) : Diagnostic Item 4: Diagnose terminator resistors at both ends.

STEP 2. Using scan tool MB991958, diagnose the CAN bus line (Disconnect combination meter connector C-04, and check the combination meter system).




1. Disconnect combination meter connector C-04.

CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.




2. Connect scan tool MB991958 to the data link connector.




3. Diagnose CAN bus lines, and check if scan tool MB991958 screen is as shown in the illustration.

Q: Does scan tool MB991958 screen correspond to the illustration?

YES: Go to Step 3.

NO: Refer to Diagnostic item 5: Diagnose when the scan tool cannot receive the data sent by combination meter.

STEP 3. Using scan tool MB991958, diagnose the CAN bus line (Disconnect ETACS-ECU connector C-218, and check the ETACS-ECU system).




1. Disconnect ETACS-ECU connector C-218.




2. Diagnose CAN bus lines, and check if scan tool MB991958 screen is as shown in the illustration.

Q: Does scan tool MB991958 screen correspond to the illustration?

YES: Go to Step 4.

NO: Refer to Diagnostic item 6: Diagnose when the scan tool cannot receive the data sent by ETACS-ECU.

STEP 4. Using scan tool MB991958, diagnose the CAN bus line (Disconnect A/C-ECU connector C-14 or C-15 , and check the A/C-ECU system).




1. Disconnect A/C-ECU connector C-14 or C-15 .

2. Diagnose CAN bus lines, and check if scan tool MB991958 screen is as shown in the illustration.

Q: Does scan tool MB991958 screen correspond to the illustration?

YES: Go to Step 5.

NO: Refer to Diagnostic item 7: Diagnose when the scan tool cannot receive the data sent by A/C-ECU.

STEP 5. Using scan tool MB991958, diagnose the CAN bus line (Disconnect SRS-ECU connector C-123, and check the supplemental restraint system).

1. Disconnect SRS-ECU connector C-123.

2. Diagnose CAN bus lines, and check if scan tool MB991958 screen is as shown in the illustration.

Q: Does scan tool MB991958 screen correspond to the illustration?

YES: Go to Step 6.

NO: Refer to Diagnostic item 9: Diagnose when the scan tool cannot receive the data sent by SRS-ECU.

STEP 6. Using scan tool MB991958, diagnose the CAN bus line (Disconnect ECM connector or PCM connector B-18, and check the ECM system or the PCM system ).

1. Disconnect ECM connector or PCM connector B-18.

2. Diagnose CAN bus lines, and check if scan tool MB991958 screen is as shown in the illustration.

Q: Does scan tool MB991958 screen correspond to the illustration?

YES: Refer to diagnostics item 13: Diagnose when the scan tool cannot receive the data sent by the ECM or the PCM and ABS-ECU or ABS/TCL-ECU or Diagnostic item 15: Diagnose when the scan tool cannot receive the data sent by the ECM or the PCM and ABS-ECU or ABS/TCL-ECU , and convertible top control module .

NO: Refer to Diagnostic item 10: Diagnose when the scan tool cannot receive the data sent by the ECM or the PCM .