Diagnostic Item 13

DIAGNOSTIC 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 .

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 "the scan tool cannot receive the sent data from the ECM or PCM and ABS-ECU or ABS/TCL-ECU " when the scan tool MB991958 checks the periodically sent data from each ECU and cannot receive ABS-ECU or ABS/TCL-ECU and ECM or powertrain control system data only.

TROUBLE JUDGEMENT CONDITIONS
Scan tool MB991958 judges the trouble when the periodically sent data from ABS-ECU or ABS/TCL-ECU and ECM or PCM cannot be received and sent.

TROUBLESHOOTING HINTS
- The wiring harness may be defective [open circuit between ABS-ECU or ABS/TCL-ECU and joint connector (3) ]
- The connector may be defective [poor connection of joint connector (3) , convertible top control module or ABS-ECU or ABS/TCL-ECU connector]
- The ABS-ECU or ABS/TCL-ECU may be defective (internal open circuit)
- The ECM or PCM may be defective (internal open circuit)

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra fine probe
- MB991970: ABS Check Harness

STEP 1. Check joint connector (3) C-03 or convertible top control module connector D-45 and ABS-ECU connector A-02 or ABS/TCL-ECU connector A-03 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

CAUTION: The strand end of the twisted wire should be within 10 cm (4.0 inches) from the connector.

Q: Are joint connector (3) C-03 or convertible top control module connector D-45 and ABS-ECU connector A-02 or ABS/TCL-ECU connector A-03 in good condition?

YES : Go to Step 2.
YES : Go to Step 4.

NO: Repair the damaged parts. Replace the joint connector as necessary.

STEP 2. Check the CAN bus lines between intermediate connector C-24 and joint connector (3). Measure the resistance between intermediate connector C-24 and joint connector (3) C-03.

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

1. Disconnect intermediate connector C-24 and joint connector (3) C-03, and measure the resistance between the wiring harness side connector of joint connector (3) C-03 and the male side connector of intermediate connector C-24 (at front wiring harness side).
2. Turn the ignition switch to the "LOCK" (OFF) position.

CAUTION: Disconnect the negative battery terminal.

3. Disconnect the negative battery terminal.

4. Measure the resistance between intermediate connector C-24 (terminal 11) and joint connector (3) C-03 (terminal 9).

OK: 2 ohms or less

5. Measure the resistance between intermediate connector C-24 (terminal 12) and joint connector (3) C-03 (terminal 20).

OK: 2 ohms or less

CAUTION: Strictly observe the specified wiring harness repair procedure.

Q: Do all the resistances measure 2 ohms or less?

YES: If all the resistances measure 2 ohms or less, go to Step 3.

NO: If either of the resistances measures more than 2 ohms or all the resistances measure more than 2 ohms, repair the wiring harness between intermediate connector C-24 and the joint connector (3) C-03.

STEP 3. Check the CAN bus lines between intermediate connector C-24 and the ABS-ECU or ABS/TCL-ECU . Measure the resistance between intermediate connector C-24 and ABS-ECU connector A-02 or ABS/TCL-ECU connector A-03 .

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

1. Disconnect intermediate connector C-24 and ABS-ECU connector A-02 or ABS/TCL-ECU connector A-03 , and measure the resistance between the wiring harness side connector of ABS-ECU connector A-02 or ABS/TCL-ECU connector A-03 and the male side connector of intermediate connector C-24 (at front wiring harness side).

2. Turn the ignition switch to the "LOCK" (OFF) position.

CAUTION: Disconnect the negative battery terminal.

3. Disconnect the negative battery terminal.

4. Measure the resistance between intermediate connector C-24 (terminal 11) and ABS-ECU connector A-02 (terminal 2).

OK: 2 ohms or less

5. Measure the resistance between intermediate connector C-24 (terminal 12) and ABS-ECU connector A-02 (terminal 8).

OK: 2 ohms or less

6. Measure the resistance between intermediate connector C-24 (terminal 11) and ABS/TCL-ECU connector A-03 (terminal 27).

OK: 2 ohms or less

7. Measure the resistance between intermediate connector C-24 (terminal 12) and ABS/TCL-ECU connector A-03 (terminal 13).

OK: 2 ohms or less

CAUTION: Strictly observe the specified wiring harness repair procedure.

Q: Do all the resistances measure 2 ohms or less?

YES: If all the resistances measure 2 ohms or less, go to Step 4.

NO: If either of the resistances measures more than 2 ohms or all the resistances measure more than 2 ohms, repair the wiring harness between intermediate connector C-24 and the ABS-ECU connector A-02 or ABS/TCL-ECU connector A-03.

STEP 4. Check the CAN bus lines between intermediate connector C-26 and convertible top control module connector D-45. Measure the resistance between intermediate connector C-26 and convertible top control module connector D-45.

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

1. Disconnect intermediate connector C-26 and convertible top control module D-45, and measure the resistance between the wiring harness side connector of convertible top control module D-45 and the male side connector of intermediate connector C-26 (at front wiring harness side).
2. Turn the ignition switch to the "LOCK" (OFF) position.

CAUTION: Disconnect the negative battery terminal.

3. Disconnect the negative battery terminal.

4. Measure the resistance between intermediate connector C-26 (terminal 15) and convertible top control module D-45 (terminal 37).

OK: 2 ohms or less

5. Measure the resistance between intermediate connector C-26 (terminal 16) and convertible top control module D-45 (terminal 38).

OK: 2 ohms or less

CAUTION: Strictly observe the specified wiring harness repair procedure.

Q: Do all the resistances measure 2 ohms or less?

YES: If all the resistances measure 2 ohms or less, go to Step 5.

NO: If either of the resistances measures more than 2 ohms or all the resistances measure more than 2 ohms, repair the wiring harness between intermediate connector C-26 and the convertible top control module D-45.

STEP 5. Check the CAN bus lines between intermediate connector C-26 and the ABS-ECU or ABS/TCL-ECU . Measure the resistance between intermediate connector C-26 and ABS-ECU connector A-02 or ABS/TCL-ECU connector A-03 .

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

1. Disconnect intermediate connector C-26 and ABS-ECU connector A-02 or ABS/TCL-ECU connector A-03 , and measure the resistance between the wiring harness side connector of ABS-ECU connector A-02 or ABS/TCL-ECU connector A-03 and the male side connector of intermediate connector C-26 (at front wiring harness side).
2. Turn the ignition switch to the "LOCK" (OFF) position.

CAUTION: Disconnect the negative battery terminal.

3. Disconnect the negative battery terminal.

4. Measure the resistance between intermediate connector C-26 (terminal 15) and ABS-ECU connector A-02 (terminal 2).

OK: 2 ohms or less

5. Measure the resistance between intermediate connector C-26 (terminal 16) and ABS-ECU connector A-02 (terminal 8).

OK: 2 ohms or less

6. Measure the resistance between intermediate connector C-26 (terminal 15) and ABS/TCL-ECU connector A-03 (terminal 27).

OK: 2 ohms or less

7. Measure the resistance between intermediate connector C-26 (terminal 16) and ABS/TCL-ECU connector A-03 (terminal 13).

OK: 2 ohms or less

CAUTION: Strictly observe the specified wiring harness repair procedure.

Q: Do all the resistances measure 2 ohms or less?

YES: If all the resistances measure 2 ohms or less, go to Step 6.

NO: If either of the resistances measures more than 2 ohms or all the resistances measure more than 2 ohms, repair the wiring harness between intermediate connector C-26 and the ABS-ECU connector A-02 or ABS/TCL-ECU connector A-03.

STEP 6. Check the CAN bus lines inside the ABS-ECU or ABS/TCL-ECU . Measure the resistance at ABS-ECU connector A-02 or ABS/TCL-ECU connector A-03 .

1. Disconnect ABS-ECU connector A-02 or ABS/TCL-ECU A-03 , and measure the resistance at the component side of ABS-ECU connector A-02 or ABS/TCL-ECU connector A-03 .

2. Measure the resistance between ABS-ECU connector A-02 (terminals 2 and 4).

OK: 2 ohms or less

3. Measure the resistance between ABS-ECU connector A-02 (terminals 8 and 6).

OK: 2 ohms or less

4. Measure the resistance between ABS/TCL-ECU connector A-03 (terminals 11 and 27).

OK: 2 ohms or less

5. Measure the resistance between ABS/TCL-ECU connector A-03 (terminals 13 and 15).

OK: 2 ohms or less

Q: Do all the resistances measure 2 ohms or less?

YES: Go to Step 7.

NO: Replace the ABS-ECU or ABS/TCL-ECU .

STEP 7. Check the terminator resistor inside the ECM or PCM . Measure the resistance at ECM or PCM connector B-18.

1. Disconnect ECM or PCM connector B-18, and measure the resistance at the component side of ECM or PCM connector B-18.

2. Measure the resistance between ECM or PCM connector terminals 17 and 18.

OK: 120 ± 20 ohms

Q: Does the resistance measure 120 ± 20 ohms?

YES: Repair the wiring harness between the ECM or PCM connector and ABS-ECU connector A-02 or ABS/TCL-ECU connector A-03 .

NO: Replace the ECM or PCM . When the ECM or PCM is replaced, register the encrypted code. Refer to Chassis Electrical - Encrypted Code Registration Criteria Table.