Traction Control

DTC U1101: CAN Communications System Time Out Error A/T Related Data

CAUTION:
^ If DTC U1101 is set in the TCL/ASC-ECU, always diagnose the CAN main bus line. If there is any fault in the CAN bus lines, an incorrect DTC may be set.
^ Whenever the TCL/ASC-ECU is replaced, ensure that the communication circuit is normal.

DTC SET CONDITION
The TCL/ASC-ECU receives A/T system-related signals from the PCM via CAN bus lines.

TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THESE DTCS ARE TO SET ARE:)
^ Damaged harness or connector.
^ Malfunction of the PCM.
^ Malfunction of the TCL/ASC-ECU.

DIAGNOSIS

Required Special Tools:
^ 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

STEP 1. Using scan tool MB991958, diagnose the CAN bus line.

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.

(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
(5) Disconnect scan tool MB991958.

Q: Is the CAN bus line found to be normal?
YES: Go to Step 2.
NO: Repair the CAN bus lines. Then go to Step 6.

STEP 2. Using scan tool MB991958, read the diagnostic trouble code.

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.

(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Check for A/T system diagnostic trouble code.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
(5) Disconnect scan tool MB991958.

Q: Is any DTC set?
YES: Repair the automatic transaxle control system. Then go to Step 6.
NO: Go to Step 3.

STEP 3. Using scan tool MB991958, read the diagnostic trouble code.

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.

(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Check if a DTC, which relates to CAN communication-linked systems below, is set.

ETACS-ECU
^ DTC U1101: Powertrain control module time-out (related to A/T).

Combination meter
^ DTC U1101: Powertrain control module time-out (related to A/T).

(4) Turn the ignition switch to the "LOCK" (OFF) position.
(5) Disconnect scan tool MB991958.

Q: Is DTC U1101 set?
YES: Go to Step 4.
NO: Go to Step 5.

STEP 4. Using scan tool MB991958, read the diagnostic trouble code.

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.

(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Use scan tool MB991958 to read the TCL/ASC diagnostic trouble codes.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
(5) Disconnect scan tool MB991958.

Q: Is DTC U1101 set?
YES: Replace the PCM. Then go to Step 6.
NO: It can be assumed that this malfunction is intermittent.

STEP 5. Using scan tool MB991958, read the diagnostic trouble code.

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.

(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Use scan tool MB991958 to read the TCL/ASC diagnostic trouble codes.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
(5) Disconnect scan tool MB991958.

Q: Is DTC U1101 set?
YES: Replace the hydraulic unit (integrated with TCL/ASC-ECU). Then go to Step 6.
NO: It can be assumed that this malfunction is intermittent.

STEP 6. Using scan tool MB991958, read the diagnostic trouble code.