Part 1

DIAGNOSTIC ITEM 4: Diagnose shorts in the ground to CAN-C bus line.

CAN-C Communication Circuit [Except Ralliart]:

CAN-C Communication Circuit [Ralliart] (Part 1):

CAN-C Communication Circuit [Ralliart] (Part 2):

FUNCTION
If a short to ground is present in the CAN-C lines, this diagnosis result will be set.

TROUBLE JUDGEMENT CONDITIONS
If DTC U1120 is set, the ETACS-ECU determines that there is a failure.

TROUBLESHOOTING HINTS
- Malfunction of the connector (short to ground inside connector)
- Malfunction of the wiring harness (short to ground in the CAN-C main or sub bus lines)
- Malfunction of the ECU (ETACS-ECU, or ECUs on CAN-C lines failed)

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

- MB991997: ASC Check Harness
- MB992110: Power Plant ECU Check Harness

STEP 1. Check the wiring harness between joint connector (CAN2) C-05 and steering wheel sensor connector C-211 for a short to ground. Measure the resistance at joint connector (CAN2) C-05.

CAUTION:
- Disconnect the negative battery terminal.
- A digital multimeter should be used.
- The test wiring harness should be used.







1. Disconnect joint connector (CAN2), and measure the resistance at the wiring harness side of joint connector (CAN2).
2. Measure the resistance between joint connector (CAN2) terminal 7 and body ground.

OK: 1 kilo ohm or more







3. Measure the resistance between joint connector (CAN2) terminal 20 and body ground.

OK: 1 kilo ohm or more

Q: Do all the resistances measure 1 kilo ohm or more?

YES [except RALLIART]: Go to Step 3.
YES [RALLIART]: Go to Step 2.

NO: Go to Step 11.

STEP 2. Check the wiring harness between joint connector (CAN2) C-05 and AWC-ECU connector C-51 for a short to ground. Measure the resistance at joint connector (CAN2) C-05.

CAUTION:
- Disconnect the negative battery terminal.
- A digital multimeter should be used.
- The test wiring harness should be used.







1. Disconnect joint connector (CAN2), and measure the resistance at the wiring harness side of joint connector (CAN2).
2. Measure the resistance between joint connector (CAN2) terminal 4 and body ground.

OK: 1 kilo ohm or more







3. Measure the resistance between joint connector (CAN2) terminal 15 and body ground.

OK: 1 kilo ohm or more

Q: Do all the resistances measure 1 kilo ohm or more?

YES: Go to Step 3.

NO: Go to Step 12.

STEP 3. Check the wiring harness between joint connector (CAN2) C-05 and ETACS-ECU connector C-301 for a short to ground. Measure the resistance at joint connector (CAN2) C-05.

CAUTION:
- Disconnect the negative battery terminal.
- A digital multimeter should be used.
- The test wiring harness should be used.







1. Disconnect joint connector (CAN2), and measure the resistance at the wiring harness side of joint connector (CAN2).
2. Measure the resistance between joint connector (CAN2) terminal 6 and body ground.

OK: 1 kilo ohm or more







3. Measure the resistance between joint connector (CAN2) terminal 19 and body ground.

OK: 1 kilo ohm or more

Q: Do all the resistances measure 1 kilo ohm or more?

YES: Go to Step 4.

NO: Go to Step 13.

STEP 4. Check the wiring harness between joint connector (CAN3) C-124 and ASC-ECU connector A-51 for a short to ground. Measure the resistance at joint connector (CAN3) C-124.

CAUTION:
- Disconnect the negative battery terminal.
- A digital multimeter should be used.
- The test wiring harness should be used.







1. Disconnect joint connector (CAN3), and measure the resistance at the wiring harness side of joint connector (CAN3).
2. Measure the resistance between joint connector (CAN3) terminal 6 and body ground.

OK: 1 kilo ohm or more







3. Measure the resistance between joint connector (CAN3) terminal 19 and body ground.

OK: 1 kilo ohm or more

Q: Do all the resistances measure 1 kilo ohm or more?

YES [except RALLIART]: Go to Step 5.
YES [RALLIART]: Go to Step 7.

NO: Go to Step 14.

STEP 5. Check the wiring harness between joint connector (CAN3) C-124 and TCM connector C-41 for a short to ground. Measure the resistance at joint connector (CAN3) C-124.

CAUTION:
- Disconnect the negative battery terminal.
- A digital multimeter should be used.
- The test wiring harness should be used.







1. Disconnect joint connector (CAN3), and measure the resistance at the wiring harness side of joint connector (CAN3).
2. Measure the resistance between joint connector (CAN3) terminal 7 and body ground.

OK: 1 kilo ohm or more







3. Measure the resistance between joint connector (CAN3) terminal 20 and body ground.

OK: 1 kilo ohm or more

Q: Do all the resistances measure 1 kilo ohm or more?

YES: Go to Step 6.

NO: Go to Step 15.

STEP 6. Check the wiring harness between joint connector (CAN3) C-124 and ECM connector B-109 [except RALLIART] for a short to ground. Measure the resistance at joint connector (CAN3) C-124.

CAUTION:
- Disconnect the negative battery terminal.
- A digital multimeter should be used.
- The test wiring harness should be used.







1. Disconnect joint connector (CAN3), and measure the resistance at the wiring harness side of joint connector (CAN3).
2. Measure the resistance between joint connector (CAN3) terminal 4 and body ground.

OK: 1 kilo ohm or more







3. Measure the resistance between joint connector (CAN3) terminal 15 and body ground.

OK: 1 kilo ohm or more


Q: Do all the resistances measure 1 kilo ohm or more?

YES: Check intermediate connector C-128, and repair if necessary. If the intermediate connector is in good condition, repair the wiring harness between joint connector (CAN2) C-05 and joint connector (CAN3) C-124.

NO: Go to Step 16.

STEP 7. Check the wiring harness between joint connector (CAN3) C-124 and shift lever connector C-49 for a short to ground. Measure the resistance at joint connector (CAN3) C-124.

CAUTION:
- Disconnect the negative battery terminal.
- A digital multimeter should be used.
- The test wiring harness should be used.







1. Disconnect joint connector (CAN3), and measure the resistance at the wiring harness side of joint connector (CAN3).
2. Measure the resistance between joint connector (CAN3) terminal 7 and body ground.

OK: 1 kilo ohm or more







3. Measure the resistance between joint connector (CAN3) terminal 20 and body ground.

OK: 1 kilo ohm or more

Q: Do all the resistances measure 1 kilo ohm or more?

YES: Go to Step 8.

NO: Go to Step 17.

STEP 8. Check the wiring harness between joint connector (CAN4) A-55 and shift lever connector B-109 [RALLIART] for a short to ground. Measure the resistance at joint connector (CAN4) A-55.

CAUTION:
- Disconnect the negative battery terminal.
- A digital multimeter should be used.
- The test wiring harness should be used.







1. Disconnect joint connector (CAN3), and measure the resistance at the wiring harness side of joint connector (CAN3).
2. Measure the resistance between joint connector (CAN3) terminal 6 and body ground.

OK: 1 kilo ohm or more







3. Measure the resistance between joint connector (CAN3) terminal 19 and body ground.

OK: 1 kilo ohm or more

Q: Do all the resistances measure 1 kilo ohm or more?

YES: Go to Step 9.

NO: Go to Step 16.

STEP 9. Check the wiring harness between joint connector (CAN4) A-55 and transaxle assembly (TC-SST-ECU) connector B-120 for a short to ground. Measure the resistance at joint connector (CAN4) A-55.

CAUTION:
- Disconnect the negative battery terminal.
- A digital multimeter should be used.
- The test wiring harness should be used.







1. Disconnect joint connector (CAN3), and measure the resistance at the wiring harness side of joint connector (CAN3).
2. Measure the resistance between joint connector (CAN3) terminal 7 and body ground.

OK: 1 kilo ohm or more







3. Measure the resistance between joint connector (CAN3) terminal 20 and body ground.

OK: 1 kilo ohm or more

Q: Do all the resistances measure 1 kilo ohm or more?

YES: Go to Step 10.

NO: Go to Step 18.