TIMING CHAIN MAINTENANCE <4B11-Turbo>



 If the vehicle equipped with 4B11-turbo engine continues the rough driving like competitive running*1, the amount of carbon mixed into the engine oil tends to increase. This can possibly cause the timing chain to gradually elongate. To prevent this, the function or logic monitoring the amount of elongation of the timing chain is integrated into the engine-ECU. When the engine-ECU detects the elongation of the timing chain, the warning is shown on the multi-information display of combination meter as shown in the illustration. This gives the driver the information that the visual check of the elongation of the timing chain is necessary. If this warning is continuously neglected, the timing chain can possibly interfere with the other engine components, resulting in the engine damaged.
note *1: The competitive running means the running that constantly repeats the cycle of the full opened position of the accelerator pedal and the full closed position of the accelerator pedal.

Service
 Maintenance items by M.U.T.-III
 Maintenance purpose
Engine-ECU replacement
  • Learned value Read&Save *2
  • Write learned value (Changed ECU)*2

 The purpose is that the initial value regarding the amount of elongation of the timing chain stored by the current engine-ECU is loaded in the M.U.T.-III, and then written into the new engine-ECU. This allows the engine-ECU to appropriately monitor the amount of elongation of the timing chain after the engine-ECU replacement.
Visual check of elongation of timing chain
 Learned value reset
 The purpose is that the initial value stored by the current engine-ECU is initialised after the visual check of the elongation of the timing chain by illuminating the warning lamp, whether or not the timing chain is replaced.
Timing chain or engine assembly replaced
 Learned value reset
 The purpose of this procedure is that the initial learning value stored by the current engine-ECU is initialised when the timing chain or the engine assembly (the timing chain is also replaced with a new one.) is replaced. This allows the engine-ECU to appropriately monitor the amount of elongation of the timing chain.
note *2: The visual check of the elongation of the timing chain must be carried out using the M.U.T.-III under the following conditions (Refer to GROUP 11E - On-vehicle Service - Timing Chain Elongation Visual Check ). When the initial value cannot be written into the new engine-ECU because of the engine-ECU malfunction.

LEARNED VALUE READ&SAVE AND WRITE LEARNED VALUE (CHANGED ECU)


1.After the ignition switch is in "LOCK" (OFF) position, connect the M.U.T.-III to the diagnosis connector.
2.Turn the ignition switch to the "ON" position.
3.Select "MPI/GDI/DIESEL" from System select Screen of the M.U.T.-III.
4.Select "Special Function" from MPI/GDI/DIESEL Screen.
5.Select "Timing chain maintenance" from Special Function Screen.
6.Select "Learned value Read&Save" from Timing chain maintenance Screen.
7.Press "OK" to store the learning value file.
note When the learning value file is appropriately stored, "Learned value Save Complete" is shown on the screen of the M.U.T.-III.
note Calculating the amount of elongation of the timing chain by the engine-ECU takes the time. Thus, the file cannot be stored for a while after the engine-ECU initialisation or replacement.
8.Replace the engine-ECU.
9.Select "Learned value reset" from Timing chain maintenance Screen.
10.Select the learning value file stored during Step 3 to write the learning value.
note Use only the learning value file stored during Step 3 without using any other files.
note When the learning value is appropriately written, "Learned value writing Completed." is shown on the screen of the M.U.T.-III.

LEARNED VALUE RESET


1.After the ignition switch is in "LOCK" (OFF) position, connect the M.U.T.-III to the diagnosis connector.
2.Turn the ignition switch to the "ON" position.
3.Select "MPI/GDI/DIESEL" from System select Screen of the M.U.T.-III.
4.Select "Special Function" from MPI/GDI/DIESEL Screen.
5.Select "Timing chain maintenance" from Special Function Screen.
6.Select "Learned value reset" from Timing chain maintenance Screen.
7.Press "OK" to reset the learning value.

TEST/LIMIT VALUE READOUT


1.After the ignition switch is in "LOCK" (OFF) position, connect the M.U.T.-III to the diagnosis connector.
2.Turn the ignition switch to the "ON" position.
3.Select "MPI/GDI/DIESEL" from System select Screen of the M.U.T.-III.
4.Select "Special Function" from MPI/GDI/DIESEL Screen.
5.Select "Timing chain maintenance" from Special Function Screen.
6.Select "Test/Limit value readout" from Timing chain maintenance Screen.
7.Read the value of percentage (%) shown on the screen.
note The value of percentage (%) shown on the screen is the amount of elongation of the timing chain calculated by the engine-ECU based on the learning value, and thus is not the actual amount. Use this for the reference only.