Issue Summary:
- Vehicles equipped with the RE4RO1A transmission may exhibit a 2nd gear start, with no first or fourth gear.
- Mitsubishi Fuso trucks have a diagnostic lamp that will flash if the automatic-transmission control unit detects a fault. We cover procedures for retrieving and clearing codes on 1988-94 and 1995 and later models.
Vehicles equipped with the RE4RO1A transmission may exhibit a 2nd gear start, with no first or fourth gear. The vehicle does shift from 2nd to 3rd gear automatically. No external problems are evident, and there is no 1st gear even when both solenoids are energized using test equipment.
Cause No. 1:
The cause may be that shift solenoid A is stuck open or has failed electrically.
Cause No. 2:
The cause may be that shift valve A in the valve body is stuck.
Cause No. 3:
The cause may be that the bore plug between shift valve A and the 4-2 relay valve in the valve body has broken at the roll pin, preventing shift solenoid A pressure from stroking the shift valve.
Correction No. 1:
Figure 1 provides a solenoid operations chart so you can manually operate the solenoids in order to verify gear selection.
Check the shift-solenoid pack for the proper resistance using the chart in Figure 2. Also energize shift solenoid A with battery voltage, using the chart in Figure 2 for the proper terminals, to ensure that it closes completely when energized. Replace the solenoid pack with Nissan part number 3 1940-41 X09 as necessary.
Correction No. 2:
Disassemble the valve body and clean thoroughly the shift valve A line-up illustrated in Figure 3.
Correction No. 3:
Check the bore plug between shift valve A and the 4-2 relay valve, making sure that no broken pieces are lodged anywhere in the valve train. Replace the bore plug as necessary (refer to Figure 3).
The diagnostic lamp shown in Figure 4 will flash 16 times if the automatic-transmission control unit (ATCU) detects a fault. If no faults are detected, the lamp will turn off in two seconds.
The code-retrieval procedure is a series of accessory operations as shown in Figure 5.
The code format is the same as for a Nissan, meaning a judgment flicker that remains on longer, then the rest is the code. The judgment flickers range from one through 10 (see the chart in Figure 6).
NOTE #1:
Only those malfunctions detected when the vehicle was previously driven remain in history.
NOTE #2:
Codes stored in memory will be erased only if the ignition is turned OFF after the code-retrieval procedure.
NOTE #3:
If vehicle speed sensors #1 and #2 fail simultaneously, the diagnostic lamp will flash.
On 1995 and later trucks, there are two procedures for retrieving codes:
Procedure #1:
Use the same code call-up procedure as for the 1988-94 models. The code format is the same as well.
Procedure #2:
If no faults are detected when the ignition is turned on, the transmission warning lamp (see Figure 7) will illuminate for two seconds and then go out. If a fault is detected, the transmission warning lamp will flash for eight seconds each time the ignition is cycled.
Locate the two single-wire diagnostic connectors under the passenger-side corner of the dashboard, close to the floor (refer to Figure 8).
One should have a yellow wire, and the other should have a green wire. Turn the ignition switch on and then unplug the diagnostic connectors. The transmission warning lamp now will flash the codes that are stored in the ATCU memory. The code pattern is a two-digit type, with the first digit producing long flashes and the second digit producing short flashes. Figure 9 provides a chart for interpreting the codes.
To clear fault codes stored in memory, locate the under-dash fuse box and remove the F10 fuse (refer to Figure 10) for at least 10 seconds.
August 2003 Issue
Volume 20, No. 8
- JR403E Electromatic: Second-Gear Starts, No First or Fourth Gear
- Mitsubishi Fuso: 1988-94 Code Retrieval
- Mitsubishi Fuso: 1995 & Later Code Retrieval
- Mitsubishi Fuso: 1995 & Later Code Clearing