COde No.U1100 Engine-related time-out


caution
  • If more than three minutes elapse after the ignition switch is turned ON without starting engine, the electric power steering-ECU may set diagnosis codes U1100 and U1102 as the M.U.T.-III shows a diagnosis code status as stored.
  • If the electric power steering-ECU sets diagnosis code No.U1100, diagnose the CAN bus lines. If there is any fault in the CAN bus lines, an incorrect diagnosis code may be set.
  • Whenever the ECU is replaced, ensure that the communication circuit is normal.


TROUBLE JUDGMENT
The electric power steering-ECU receives engine speed data (crankshaft angle sensor data) from the engine-ECU <M/T> or engine-A-M/T-ECU <Automated manual transmission> through the CAN bus lines. If the ECU cannot receive the engine speed data (crankshaft angle sensor data) from the engine-ECU <M/T> or engine-A-M/T-ECU <Automated manual transmission> for 60 seconds, diagnosis code U1100 will be set.

COMMENTS ON TROUBLE SYMPTOM
The M.U.T.-III shows a diagnosis code status as active
  • Defective harness wire(s) or connector(s) in the CAN bus lines between the engine-ECU <M/T> or the engine-A-M/T-ECU <Automated manual transmission> and the electric power steering-ECU, or the power supply to these ECUs, or the ECUs themselves are defective.
The M.U.T.-III shows a diagnosis code status as stored
  • Carry out diagnosis by referring to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with The M.U.T.-III shows a diagnosis code status as stored ). Carry out diagnosis with particular emphasis on connector(s) or wiring harness in the CAN bus lines between the engine-ECU <M/T> or engine-A-M/T-ECU <Automated manual transmission> and the electric power steering-ECU, and the power supply to the engine-ECU <M/T> or engine-A-M/T-ECU <Automated manual transmission>.
    note For a The M.U.T.-III shows a diagnosis code status as stored, you can not find it by the M.U.T.-III CAN bus diagnostics even if there is any failure in CAN bus lines. In this case, refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points-How to Cope with Intermittent Malfunction and check the CAN bus lines. You can narrow down the possible cause of the trouble by referring to the diagnosis code, which is set regarding the CAN communication-linked ECUs (Refer to GROUP 54C - CAN Bus Line Diagnostic Flow ).

PROBABLE CAUSES

  • Defective harness wire(s) or connector(s)
  • Malfunction of the engine-ECU <M/T> or engine-A-M/T-ECU <Automated manual transmission>
  • Malfunction of the electric power steering-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics

caution Before connecting or disconnecting the M.U.T.-III, turn the ignition switch to the "LOCK" (OFF) position.
(1)Connect M.U.T.-III to the 16-pin diagnosis 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.

Q. Is the check result normal?

Go to Step 2.

Repair the CAN bus line (Refer to GROUP 54C - CAN bus line Diagnostic flow ). Then go to Step 2.

STEP 2. M.U.T.-III other system diagnosis code

caution Before connecting or disconnecting the M.U.T.-III, turn the ignition switch to the "LOCK" (OFF) position.
Check again if the diagnosis code is set.
(1)Turn the ignition switch to the "ON" position.
(2)Erase the diagnosis code.
(3)Turn the ignition switch to the "LOCK" (OFF) position.
(4)Turn the ignition switch to the "ON" position.
(5)Check that an engine control system diagnosis code is set.
(6)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the diagnosis code set?

Diagnose the engine control system (Refer to GROUP 13A - Troubleshooting - Inspection chart for diagnosis code <134 or 3A9>, GROUP 13B - Troubleshooting - Inspection chart for diagnosis code <135 or 4A9> or GROUP 13C - Troubleshooting - Inspection chart for diagnosis code <4G1>).

Go to Step 3.

STEP 3. M.U.T.-III data list
Set the M.U.T.-III to the data reading mode, and check the data list item (when the engine starts).

  • Item 12: Engine speed
OK: The reading on the tachometer nearly match the indication on M.U.T.-III.

Q. Is the engine speed input normal?
Go to Step 4.
Replace the engine-ECU <M/T> or engine-A-M/T-ECU <Automated manual transmission> (Refer to GROUP 13A - Engine-ECU <134 or 3A9>, GROUP 13B - Engine-ECU, Engine-A-M/T-ECU <135 or 4A9>, GROUP 13C - Engine-ECU <4G1>).

STEP 4. Check whether the diagnosis code is reset

caution Before connecting or disconnecting the M.U.T.-III, turn the ignition switch to the "LOCK" (OFF) position.
Check again if the diagnosis code is set.
(1)Turn the ignition switch to the "ON" position.
(2)Erase the diagnosis code.
(3)Turn the ignition switch to the "LOCK" (OFF) position.
(4)Turn the ignition switch to the "ON" position.
(5)Start the engine and wait for at least 60 seconds.
(6)Recheck whether diagnosis code U1100 is set.
(7)Turn the ignition switch to the "LOCK" (OFF) position.
(8)Disconnect M.U.T.-III.

Q. Is diagnosis code U1100 set?

Replace the electric power steering-ECU (Refer to ).

The malfunction is intermittent. Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction .