Inspection Procedure 3

INSPECTION PROCEDURE 3: Does not Move Backward

COMMENT

If the vehicle does not move backward when the selector lever is shifted from "N" to "R"
range while the engine is idling, the cause is probably abnormal pressure or a malfunction of the reverse clutch, low-reverse brake, or valve body.

TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THIS CONDITION:)

- Abnormal reverse clutch pressure
- Abnormal low-reverse brake pressure
- Malfunction of the low-reverse solenoid valve
- Malfunction of the reverse clutch
- Malfunction of the low-reverse brake
- Malfunction of the valve body
- Malfunction of the PCM

DIAGNOSIS

Required Special Tools:

- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, check actuator test item 1: Low-Reverse Solenoid Valve.





(1)
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.

Connect scan tool MB991958 to the data link connector.
(2)Turn the ignition switch to the "ON" position.
(3)Set scan tool MB991958 to the actuator test mode.

- Item 1: Low-Reverse Solenoid Valve.
- An audible clicking or buzzing should be heard when the low-reverse solenoid valve is energized.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the solenoid valve operating properly?

YES Go to Step 2.

NO Repair or replace the low-reverse solenoid valve. Valve Body Disassembly and Assembly [4A/T]
or [5A/T]. Then confirm that the symptom is eliminated.

STEP 2. Check the hydraulic pressure (for reverse clutch).

Measure the hydraulic pressure for the reverse clutch when the selector lever is at the
"R" range, and check if the hydraulic pressure is within the standard value. Refer to Hydraulic Pressure Test, Hydraulic Pressure Test.

Q. Is the hydraulic pressure within the standard value?

YES Go to Step 3.
NO Go to Step 5.
STEP 3. Check the hydraulic pressure (for low-reverse brake).

Measure the hydraulic pressure for the low-reverse brake when the selector lever is at the "R" range, and check if the hydraulic pressure is within the standard value. Refer to Hydraulic Pressure Test, Hydraulic Pressure Test.

Q. Is the hydraulic pressure within the standard value?

YES Go to Step 4.
NO Go to Step 5.
STEP 4. Check the reverse clutch system and low-reverse brake system.

(1)Remove the valve body cover and valve body. Transaxle Disassembly and Assembly [4A/T]
or [5A/T].





(2)Blow 108 kPa (15psi) compressed air into the reverse clutch oil orifice of the transaxle case. Then check if the reverse clutch piston moves and air pressures are maintained in that condition. Repeat for the low-reverse brake.

Q. Are the reverse clutch, low-reverse brake or both air pressures maintained?

YES Go to Step 5.

NO Go to Step 6.

STEP 5. Disassemble and clean the valve body.





Check the O-ring installation bolts for looseness and valve body for damage. Repair or replace the faulty parts. Valve Body Disassembly and Assembly [4A/T]
or [5A/T].
Replace the valve body assembly if the damages are thought to be irreparable. Then check the symptom.

Q. Is the symptom eliminated?

YES The procedure is complete.

NO Go to Step 7.

STEP 6. Check the reverse clutch, low-reverse brake or both. Remove the transaxle.





Check the facing for seizure and the piston seal ring for damage and interference with the retainer. Repair or replace the faulty parts. Transaxle Disassembly and Assembly, Reverse and Overdrive Clutch Reverse and Overdrive Clutch Disassembly and Assembly [4A/T] or , Reverse and Overdrive Clutch [5A/T]. Then check the symptom.

Q. Is the symptom eliminated?

YES The procedure is complete.

NO Go to Step 7.

STEP 7. Replace the PCM.

When the PCM is replaced, register the encrypted code. Encrypted Code Registration Criteria Table.

Q. Is the symptom eliminated?

YES The procedure is complete.
NO Start over at Step 1.