18I/Sportwagon L4-1647cc 100 CID (1982)
Automatic Transmission/Transaxle: Technical Service Bulletins
A/T - No-Shift Problem Diagnosis
TSB 87 - 16 (Mar)
SUBJECT: RENAULT MB1-MJ TRANSAXLE
PROBLEM:
How to determine whether the no-shift problem is in the computer or transmission -- electrical or mechanical.
SOLUTION:
Fabricate a tool (see Figure 1)
Make a single jumper wire, about 212 to 3 feet long. Insert a 20 amp in-line fuse in this wire. Now, connect an alligator clip on each end of the wire.
Make a wish-bone wire -- that is, two wires about the same length as the first wire. Connect two of the ends together and install an alligator clip. Install
alligator clips on the remaining two ends of the wish-bone.
NOW THAT YOU HAVE THE TOOL, follow the shift solenoid wires from the transmission to the computer. Unplug the shift solenoid wiring harness
connector at the computer. The computer is usually located on the left front wheel well, or shock tower. BE SURE TO IDENTIFY the "A", "B" and "C"
terminals on the shift solenoid wiring harness connector. MAKE SURE THE DRIVING WHEELS ARE OFF THE FLOOR.
Attach one end of the single jumper wire to the connector marked "C". Attach the other end to the positive terminal of the battery. Connect the single
wire end of the wishbone to the ground, connect one terminal on the other end of the wishbone to "B". Start the engine and put the selector in drive.
Depress the accelerator slightly -- the transmission should be in 1st gear. Attach the last lead of the wishbone to the "A" terminal. The transmission
should shift into second gear. Remove the single jumper wire from "C" terminal. The transmission should shift into third gear. IF THE
TRANSMISSION MAKES THESE SHIFTS, THE PROBLEM IS NOT MECHANICAL.
The problem is either a blown fuse to the computer; the computer; or one of its sensors. If the transmission makes NONE of these shifts, there is an
electrical problem, either inside the unit, or within the wiring harness to the transmission. If any one, or all the shifts do not occur, the problem may be
solenoids or mechanical difficulties.
