Diagnostics Item 11

DIAGNOSTIC ITEM 11: Diagnose the lines between CAN main bus line and the powertrain control module

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.














TROUBLE JUDGMENT

If the M.U.T.-III cannot received signals from the powertrain control module, CAN bus line connector(s) are broken or an open circuit has occurred.

COMMENTS ON TROUBLE SYMPTOM

The wiring harness wire or connectors may have loose, corroded, or damage terminals, or terminals pushed back in the connector, or the powertrain control module may be defective.

TROUBLESHOOTING HINTS

- The wiring harness or connectors may have loose, corroded, or damage terminals, or terminals pushed back in the connector
- The powertrain control module may be defective
- The TCL/ASC-ECU may be defective

DIAGNOSIS

Required Special Tools:

- MB991223: Harness Set
- MB991970: ABS Check Harness
- MB991923: Power Plant ECU Check Harness

STEP 1. Check TCL/ASC-ECU connector A-42 and powertrain control module connector B-19 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 inches) from the connector.
For details refer to Precautions When CAN Bus Line(S) Are Repaired.

Q. Are TCL/ASC-ECU connector A-42 and powertrain control module connector B-19 in good condition?

YES Go to Step 2.

NO Repair the damaged parts.

STEP 2. Check the CAN bus lines between the TCL/ASC-ECU and the powertrain control module. Measure the resistance between TCL/ASC-ECU connector A-42 and powertrain control module connector B-19.

CAUTION:
A digital multimeter should be used. For details refer to Precautions When CAN Bus Line(S) Are Repaired.

CAUTION:
The test wiring harness should be used. For details refer to Precautions When CAN Bus Line(S) Are Repaired.









(1)Disconnect TCL/ASC-ECU connector A-42 and powertrain control module connector B-19, and measure the resistance between each wiring harness side connector.
(2)Turn the ignition switch to the "LOCK" (OFF) position.

CAUTION:
Disconnect the negative battery terminal. For details refer to Precautions When CAN Bus Line(S) Are Repaired.

(3)Disconnect the negative battery terminal.





(4)Measure the resistance between TCL/ASC-ECU connector terminal 15 and powertrain control module connector terminal 18.
OK: 2 ohms or less






(5)Measure the resistance between TCL/ASC-ECU connector terminal 11 and powertrain control module connector terminal 17.
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 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 TCL/ASC-ECU connector and the powertrain control module connector.

STEP 3. Check the CAN bus lines inside the TCL/ASC-ECU. Measure the resistance at TCL/ASC-ECU connector A-42.

CAUTION:
A digital multimeter should be used. For details refer to Precautions When CAN Bus Line(S) Are Repaired.

CAUTION:
The test wiring harness should be used. For details refer to Precautions When CAN Bus Line(S) Are Repaired.





(1)Disconnect TCL/ASC-ECU connector A-42, and measure the resistance at the component side of TCL/ASC-ECU connector A-42.
(2)Turn the ignition switch to the "LOCK" (OFF) position.
(3)
CAUTION:
Disconnect the negative battery terminal. For details refer to Precautions When CAN Bus Line(S) Are Repaired.

Disconnect the negative battery terminal.





(4)Measure the resistance between TCL/ASC-ECU connector terminals 13 and 15.
OK: 2 ohms or less






(5)Measure the resistance between TCL/ASC-ECU connector terminals 27 and 11.
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 If all the resistances measure 2 ohms or less, power supply to the powertrain control module may be suspected. Diagnose the engine. Inspection Procedure 1 [2.4L engine].

NO If either of the resistances measures more than 2 ohms or all the resistances measure more than 2 ohms, replace the TCL/ASC-ECU.